DESCRIPTION
[Title of Invention]
PLAYBACK DEVICE, PLAYBACK METHOD,
PLAYBACK PROGRAM, AND INTEGRATED CIRCUIT
[Technical Field]
The present invention relates to a technology for
playing back a stereoscopic video image and especially to a
technology for displaying a stereoscopic video image
superimposed with a graphics image.
[Background Art]
In recent years, an increasing number of digital
contents have been recorded on read-only Blu-ray discs (TM),
namely, BD-ROM discs. In line with the increase, the use of
playback devices conforming to the BD-ROM standard, namely,
BD-ROM playback devices, has been spreading at a rapid pace.
A content recorded on a BD-ROM disc includes at least one title.
The "title" is represented by a combination of application
programs, video/audio streams, and image data. The image data
represents graphics images of subtitles, a graphics user
interface (GUI) and the like, and background images. The
video/audio streams and the image data each include a variety
of types from which suitable ones can be selected in various
playback environments. In particular, the video streams can
have a variety of resolutions ranging from 720x480 for the
standard definition by the NTSC standard up to 1920x1080 for
high definition. For example, when a user specifies a title,
the BD-ROM playback device reads application programs
corresponding to the title from a BD-ROM disc, and executes the

application programs. The application programs cause the
BD-ROM playback device to select, from the image data for the
title, data suitable for the playback environment, and write
the selected data pieces into different plane memories
depending on which types the data pieces are; video, graphics,
or background. The data stored in the plane memories, namely,
planes, are processed in parallel with each other, and then
synthesized into one video frame. In this way, the BD-ROM
playback device can reproduce appropriate video/audio outputs
on various display devices (see, for example, Patent Literature
1) •
According to the BD-ROM standard, when the playback
device can be connected with an external network such as the
Internet, the application programs can cause the playback
device to download digital contents from the external network.
The contents that can be downloaded include additional contents
to the contents recorded on the BD-ROM disc such as bonus video
images and subtitles, and interactive contents such as browser
screens and games. The application programs can further cause
the playback device to display the downloaded subtitles
superimposed on the video images being played back from the
BD-ROM disc, and display the downloaded browser screen
superimposed on the screen on which the video images are
displayed. These functions are called "BD-Live" (TM) . As the
use of BD-ROM playback devices has been spreading, an increasing
number of users have been interested in the BD-Live function.
The spread of the BD-ROM playback devices has also
increased the possibility that the display technology of the
stereoscopic video images (also referred to as
three-dimensional (3D) video images) may be used in homes . The

display technology of stereoscopic video images is expected to
become a next-generation display technology, and is being
developed at a rapid pace. The display technology of
stereoscopic video images basically uses the fact that "a person
perceives the three-dimensional shape and depth of an object
from binocular parallax" (see, for example, Patent Literatures
1 through 3 and Non-Patent Literature 1) . More specifically,
first, two video frames (namely, a left-view video frame and
a right-view video frame) are prepared for one scene. The two
video frames slightly differ in the horizontal location and
position of the same object. Next, the left-view video frame
is projected to the left eye of a viewer, and substantially at
the same time, the right-view video frame is projected to the
right eye of the viewer. At that time, the viewer perceives
the three-dimensional shape and depth of the object from
binocular parallax, namely, a slight change in location and
position of the object between the frames projected to both eyes
of the viewer. Thus, the display technology of stereoscopic
video images requires two frames for each scene. Accordingly,
stereoscopic video images require a larger amount of data for
a fixed display time than monoscopic video images (also referred
to as two-dimensional (2D) video images). For this reason,
BD-ROM discs and BD-ROM playback devices have an advantage in
the display technology of stereoscopic video images.
[Citation List]
[Patent Literature]
[Patent Literature 1]
WO 2005/119675, pamphlet
[Patent Literature 2]

U.S. Publication No. 2008/0036854, specification
[Patent Literature 3]
U.S. Publication No. 2002/0118275, specification
[Non-Patent Literature]

[Non-Patent Literature 1]
Lenny Lipton, "Foundations of the Stereoscopic Cinema",
Van Nostrand Reinhold, New York, 1982
[Summary of Invention]
[Technical Problem]
As described above, the BD-ROM playback device is
implemented with a lot of plane memories. Furthermore, each
plane has a capacity that is sufficient enough to deal with
high-quality images of 1920x1080. Still furthermore, an image
data area is provided in the memory device that is embedded in
the BD-ROM playback device. The image data area stores image
data in a decoded form after the image data was read from the
BD-ROM disc. The image data pieces stored in the image data
area are written into different plane memories depending on
which types the image data pieces are; for example, interactive
screen and background. In addition to these, when the BD-Live
function is implemented into the BD-ROM playback device, a cache
area is provided in the embedded memory device. The cache area
stores image data downloaded from the external network. As
described so far, the BD-ROM playback device requires
large-capacity memory for storing and processing the image data.
Therefore when the display function of stereoscopic video
images is added into the BD-ROM playback device, the greatest

possible reduction in the capacity of memory to be added, such
as the necessary capacity of additional plane memories, is
desirable for suppressing an increase in manufacturing cost of
the playback device as much as possible.
According to conventional display technologies of
stereoscopic video images, two types of video streams, namely,
left-view and right-view video streams, are prepared on a
recording medium. Therefore, two plane memories for video
streams are implemented in a usual playback device. On the
other hand, two different types of image data each representing
usual monoscopic images, one type for graphics images and the
other for background images, are prepared on the recording
medium. The playback device first generates one image plane
from each type of the image data. The playback device next
shifts individual monoscopic video images to the left or right
in the horizontal direction within the image plane, and thus
generates a pair of left-view and right-view image planes. In
order to perform these processes, for example, the playback
device only has to be implemented with one plane memory for each
of subtitles, interactive screens, and background images.
This structure suppresses the total capacity of the plane
memories to be implemented in the playback device.
However, limited stereoscopic effect on graphics and
background images can be represented by the pairs of image
planes generated as described above. On the other hand, further
improvement in the user experience of stereoscopic video images,
desires further enhancement of the stereoscopic effect on
graphics and background images . For this reason, for each of
graphics and background images, it is preferable that both the
left-view and right-view image data types are prepared on the

recording medium.
In order to hold both the left-view and right-view image
planes without adding any plane memory in the playback device,
the memory area for storing the image data may be changed
dynamically. Especially, since the use frequency of the
BD-Live function is generally low, it would be sufficient that
the cache area used for the BD-Live function can be also used
to hold the left- and right-view image planes. However, in
conventional playback devices, both the memory area for storing
image data and the cache area are fixed from the hardware
environment such as whether or not the playback device is
connected with an external network. Furthermore, application
programs belonging to each title are designed on the assumption
of the static allocation of memory areas. In particular,
application programs using the BD-Live function require a cache
area whose capacity is equivalent to a fixed value. Therefore,
if memory areas are changed while such application programs are
executed, there is a risk that a malfunction may occur. For
example, image data downloaded by the application programs from
the external network may be written into a memory area different
from the cache area.
An object of the present invention is therefore to solve
the above-described problems, and especially to provide a
playback device that can play back digital contents with higher
stereoscopic effects of graphics images but without increasing
memory capacity.
[Solution to Problem]
A playback device according to an embodiment of the
present invention includes a reading unit, a virtual machine

unit, a memory unit, a playback unit, and a management unit.
The reading unit reads an application program, image data, a
video stream, and an application management file from a
recording medium. The virtual machine unit executes the
application program. The memory unit includes an image data
area for storing the image data. The playback unit plays back
video data with use of the image data and the video stream in
accordance with the application program. The management unit,
in accordance with the application management file, instructs
the virtual machine unit to start and terminate the application
program and instructs the memory unit to change the image data
area. The management unit further causes the virtual machine
unit to forcibly terminate the application program before
instructing the memory unit to change the image data area, even
when the application management file specifies continuous
execution of the application program.
[Advantageous Effects of Invention]
The playback device of the present invention forcibly
terminates application programs read from a recording medium,
and after that, changes the image data area. Thus, the playback
device can dynamically change the image data area while reliably
preventing a malfunction of the application programs. As a
result, it is possible to reduce the image data area, and then
use a free area available by the reduction to store both the
left-view and right-view image planes. In this way, the
playback device of the present invention can play back digital
contents with higher stereoscopic effects of graphics images
but without increasing memory capacity.

[Brief Description of Drawings]
Fig. 1 is a schematic diagram showing a home theater
system including a playback device according to Embodiment 1
of the present invention.
Fig. 2 is a schematic diagram showing the data structure
of the BD-ROM disc 100 according to Embodiment 1 of the present
invention.
Fig. 3 is a schematic diagram showing an index table 310
in the index file 231 shown in Fig. 2.
Figs. 4A and 4B are schematic diagrams showing images
displayed on the screen 121 of the display device 120 in the
HDMV mode and the BD-J mode, respectively.
Figs. 5A through 5D show an example of generating a left
view 502L and a right view 502R from a 2D video image 501 in
the offset mode.
Fig. 6A is a schematic diagram showing the data structure
of the BD-J object, and Fig. 6B is a schematic diagram showing
life cycles of six types of application programs A1-A5 and All.
Fig. 7 shows the state transition among the states 1-4
of the playback device in Embodiment 1 of the present invention.
Fig. 8 is a schematic diagram showing the data structure
of the JAR file 237A shown in Fig. 2.
Figs. 9A and 9B are schematic diagrams showing the
elementary streams multiplexed in the first AV stream file 235A
and the second AV stream file 235B shown in Fig. 2, respectively.
Fig. 10 is a schematic diagram showing the arrangement
of the packets of the elementary streams 1001, 1004, 1007, and
1010 multiplexed in the first AV stream file 235A shown in Fig.
2.
Fig. 11 is a schematic diagram showing the data structure

of the first clip information file 234A shown in Fig. 2.
Fig. 12 is a schematic diagram showing the data structure
of the 3D metadata 1103 shown in Fig. 11.
Fig. 13 is a schematic diagram showing the data structure
of the second playlist file 233B shown in Fig. 2.
Fig. 14 is a schematic diagram showing the data structure
of the playitem information 1400 shown in Fig. 13.
Fig. 15 is a schematic diagram showing the playlist
information 13 01 shown in Fig. 13 and the AV clips CL1, CL2,
and CL4 that are to be played back in accordance with the playlist
information 1301.
Fig. 16 is a block diagram showing the hardware structure
of the playback device 110 in Embodiment 1 of the present
invention.
Fig. 17 is a functional block diagram showing the
structure of the control unit 1650 shown in Fig. 16.
Fig. 18 is a functional block diagram showing the
structure of the playback unit 1660 shown in Fig. 16.
Fig. 19 is a schematic diagram showing one example of the
IG plane memory area, PG plane memory area, BG plane memory area,
and image data area that are ensured in the image memory 1810
shown in Fig. 18.
Fig. 2 0 is a schematic diagram showing the image planes
stored in the IG plane memory area 1911 shown in Fig. 19 in the
offset mode and 2-plane mode.
Fig. 21 is a functional block diagram showing the addition
unit 1807 shown in Fig. 18 in the state 1.
Fig. 22 is a functional block diagram showing the addition
unit 1807 shown in Fig. 18 in the state 2.
Fig. 23 is a schematic diagram showing the cropping

process performed onto the PG plane GP by the second cropping
processor 2212 shown in Fig. 22.
Fig. 24 is a functional block diagram showing the addition
unit 1807 shown in Fig. 18 in the states 3 and 4.
Fig. 25 is a flowchart showing the process for switching
between the states of the playback device 110 by the BD-J module
1745 shown in Fig. 17.
Fig. 2 6 is a flowchart of an event process performed by
the application program in the playback device of Embodiment
2 of the present invention.
[Description of Embodiments]
The following describes preferred embodiments of the
present invention with reference to the drawings.
[0016] [Embodiment 1]
Fig. 1 is a schematic diagram showing a home theater
system including a playback device according to Embodiment 1
of the present invention. With reference to Fig. 1, the home
theater system includes a recording medium 100, a playback
device 110, a display device 120, shutter glasses 130, and a
remote control 14 0.
The recording medium 100 is a BD-ROM disc. The
recording medium 100 can be a different portable recording
medium, such as an optical disc with a different format such
as DVD or the like, a magnetooptical disc, a flexible disk, a
removable hard disk drive (HDD), or a semiconductor memory
device such as an SD memory card. The BD-ROM disc 100 stores
a movie content as a 3D video image. The movie content includes
a pair of a left-view video stream and a right-view video stream.
A BD-ROM drive 111 is mounted on the playback device

110. The BD-ROM drive 111 is an optical disc drive conforming
to the BD-ROM format. The playback device 110 uses the BD-ROM
drive 111 to read the movie content from the BD-ROM disc 100.
The playback device 110 further decodes the movie content into
video data/audio data. When the playback device 110 or the
display device 120 supports only display of a plane image (also
referred to as a two-dimensional (2D) image), then the video
data only includes either a left-view or a right-view video
frame. On the other hand, when both the playback device 110
and the display device 120 support display of a 3D image, then
the video data includes both left-view and right-view video
frames.
The playback device 110 is connected to the display
device 120 via an HDMI (High-Definition Multimedia Interface)
cable 112. The playback device 110 converts the video
data/audio data into a video signal/audio signal in the HDMI
format and sends the signals to the display device 120 via the
HDMI cable 112. Additionally, the playback device 110
exchanges CEC messages with the display device 12 0 via the HDMI
cable 112 . In this way, the playback device 110 asks the display
device 120 whether it supports display of 3D video images.
The playback device 110 is connected with an external
network 150 such as the Internet, and can communicate with the
server device 160 via the external network 150. Especially,
the playback device 110 supports the BD-Live function. With
this function, the playback device 110 can download a new
content from the server device 160 and play back the downloaded
content. The new content includes an additional content and
an interactive content, where the additional content is to be
added to the movie content stored in the BD-ROM disc 100. The

additional content includes a sub-audio, subtitles, and an
application program to be added to the movie content, and a bonus
image pertaining to the movie content. The interactive content
includes a browser screen and a game. When the playback device
110 plays back the video image stored in the BD-ROM disc 100,
it superimposes the image, such as a subtitle, of the additional
content onto the video image, or displays the video image
together with the image, such as a browser screen, of the
interactive content, on the same screen.
The display device 120 is a liquid crystal display.
Alternatively, the display device 12 0 can be another type of
flat panel display, such as a plasma display or an organic EL
display, or a projector. The display device 120 displays video
on the screen 121 in accordance with a video signal, and causes
an embedded speaker to produce audio in accordance with an audio
signal. Especially, when the playback device 110 and the
display device 12 0 both support display of 3D video images, then
the left-view and the right-view are displayed alternately on
the screen 121.
When the display device 12 0 supports display of 3D video
images, a left/right signal transmitting unit 122 is further
mounted on the display device 120. The left/right signal
transmitting unit 122 transmits a left/right signal LR to the
shutter glasses 13 0 via infrared rays or by radio transmission.
The left/right signal LR indicates whether the image currently
displayed on the screen 121 is a left-view or a right-view video
frame. The display device 120 distinguishes between a
left-view video frame and a right-view video frame using the
control signal that accompanies a video signal and causes the
left/right signal transmitting unit 122 to change the

left/right signal LR in synchronization with the switching
between video frames.
The shutter glasses 13 0 include two liquid crystal
display panels 131L and 131R and a left/right signal receiving
unit 132. The liquid crystal display panels 131L and 131R
constitute the left and right lens portions, respectively. The
left/right signal receiving unit 132 receives a left/right
signal LR, and in accordance with the change of the received
left/right signal LR, sends a signal to the left and right liquid
crystal display panels 131L and 131R. In accordance with the
signal, each of the liquid crystal display panels 131L and 131R
either lets light pass through the entire panel or shuts light
out. For example, when the left/right signal LR indicates a
left-view display, the liquid crystal display panel 131L for
the left eye lets light pass through, while the liquid crystal
display panel 131R for the right eye shuts light out. When the
left/right signal LR indicates a right-view display, the
display panels act oppositely. In this way, the two liquid
crystal display panels 131L and 131R alternately let light pass
through in sync with the switching between frames . As a result,
when a viewer looks at the screen while wearing the shutter
glasses 130, the left-view is shown only to the viewer's left
eye, and the right-view is shown only to the right eye. At that
time, the viewer is made to perceive the difference between the
images seen by each eye as the binocular parallax for a single
virtual three-dimensional object. That is to say, the viewer
views the two video frames as one virtual three-dimensional
object.
The remote control 14 0 includes an operation unit and
a transmitting unit. The operation unit includes a plurality

of buttons. The buttons correspond to each of the functions
of the playback device 110 and the display device 120, such as
turning the power on or off, starting or stopping playback of
the BD-ROM disc 100, etc. The operation unit detects when the
user presses a button and passes a signal that specifies the
button to the transmitting unit. The transmitting unit sends
this signal as a signal IR via infrared rays or radio
transmission to the playback device 110 or the display device
120. In this way, the user can remotely control the playback
device 110 or the display device 120.
>
As further shown in Fig. 2, in the directory/file
structure 214 on the BD-ROM disc 100, a BD movie (BDMV) directory
23 0 and a CERTIFICATE directory 24 0 are located immediately
below a ROOT directory 220. The BDMV directory 230 stores the
body of the content. The CERTIFICATE directory 24 0 stores
information necessary for authentication of the content.

Below the BDMV directory 23 0 are an index file
(index.bdmv) 231 and a movie object file (MovieObject .bdmv) 232.
The index file 231 contains information for managing as a whole
the content recorded on the BD-ROM disc 100. The movie object
file 232 generally stores a plurality of movie objects. Each
"movie object" stores a sequence of instructions for causing
the playback device 110 to execute playback processes in a
similar manner to general DVD players. Especially, the movie
object file 232 includes a movie object for causing the playback
device 110 to execute the playback process for 2D video images,
and a movie object for causing the playback device 110 to execute
the playback process of 3D video images.
The BDMV directory 23 0 further contains a playlist
(PLAYLIST) directory 233; a clip information (CLIPINF)
directory 234; a stream (STREAM) directory 235; a BD-J object
(BDJO: BD Java™ Object) directory 236; and a Java archive (JAR:
Java Archive) directory 237.
AV stream files (01000.m2ts) 235Aand (02000.m2ts) 235B
are located in the STREAM directory 235. An "AV stream file"
is the body of a video content and represents video, audio,
subtitles, etc. The types of AV stream files include a 2D/AV
stream file, a left-view AV stream file, and a right-view AV
stream file. A "2D/AV stream file" refers to an AV stream file
that can be used alone for playback of 2D video images. A
"left-view stream file" refers to an AV stream file representing
the left-view of 3D video images. A "right-view stream file"
refers to an AV stream file representing the right-view of 3D
video images. A left-view stream file and a right-view stream
file are used as a pair to display 3D video images. In the
example shown in Fig. 2, the first AV stream file (01000.m2ts)

235A is a 2D/AV stream file and is also a left-view stream file.
The second AV stream file (02000.m2ts) 235B is a right-view
stream file, and is used in combination with the first AV stream
file 235A for playback of 3D video images.
Clip information files (01000. clpi) 234A and
(02000.clpi) 234B are located in the CLIPINF directory 234.
Each "clip information file" is assigned one-to-one to an AV
stream file, and mainly represents the correspondence between
the presentation times of the video images shown by the AV stream
file and the logical addresses in the AV stream file. The types
of clip information files include a 2D clip information file,
a left-view clip information file, and a right-view clip
information file, which are clip information files respectively
corresponding to a 2D/AV stream file, a left-view stream file,
and a right-view stream file. In the example shown in Fig. 2,
the first clip information file (01000. clpi) 234A is a 2D clip
information file and is also a left-view clip information file
corresponding to the first AV stream file (01000.m2ts) 235A.
The second clip information file (02000. clpi) 234B is a
right-view clip information file corresponding to the second
AV stream file (02000.m2ts) 235B.
Playlist files, (00001.mpls) 233A and (00002.mpls)
233B are located in the PLAYLIST directory 233. A "playlist
file" specifies the playback path of an AV stream file, namely,
the portion of an AV stream file to decode, and the order of
decoding. The types of playlist files include a 2D playlist
file and a 3D playlist file. A "2D playlist file" refers to
a playlist file specifying the playback path of a 2D/AV stream
file. A "3D playlist file" refers to a playlist file that
specifies the playback path of a combination of a left-view

stream file and a right-view stream file. In the example shown
in Fig. 2, the first playlist file (00001.mpls) 233A is a 2D
playlist file, and the second playlist file (00002.mpls) 233B
is a 3D playlist file.
BD-J object files (XXXXX.bdjo) 236A and (yyyyy.bdjo)
236B are located in the BDJO directory 236. The "BD-J object
file" includes a single BD-J object. The "BD-J object" is a
bytecode program that specifies (i) an application program to
be executed by a Java virtual machine implemented in the
playback device 110, and (ii) the execution time of the
application program. The application program causes the
playback device 110 to execute the title playback process and
the graphics image rendering process. In the example shown in
Fig. 2, the BD-J object stored in the first BD-J object file
(XXXXX.bdjo) 236A causes the playback device 110 to execute the
2D image playback process. On the other hand, the BD-J object
stored in the second BD-J object file (yyyyy.bdjo) 236B causes
the playback device 110 to execute the 3D image playback
process.
JAR files (XXXXX.jar) 237A and (yyyyy.jar) 237B are
located in the JAR directory 237. The "JAR file" includes
bodies of more than one application programs, in general, that
the BD-J object specifies to be executed.
Below the CERTIFICATE directory 240, an application
certificate file (app.discroot.crt) 241 is located. The
application certificate file 241 is unique to the content
provider recorded on the BD-ROM disc 100. The "application
certificate file" is what is called a digital certificate, and
is used for signature verification of the application program.
In the signature verification, it is checked whether or not the

application program has been tampered with, and the supply-
source thereof is authenticated. With the signature
verification, it is possible to cause the Java virtual machine
to activate only the application program being permitted by the
content provider, or it is possible to selectively authorize
the application program to access the memory within the playback
device 110.
In the following, the data structure of each of the files
in the BDMV directory 23 0 will be described.
<< Index table >>
The index file 231 contains information that is
necessary for identification of the BD-ROM disc 100. When the
BD-ROM disc 10 0 is inserted into the BD-ROM drive 111, the index
file 231 is read first and used by the control unit of the
playback device 110 to identify the BD-ROM disc 100. The index
file 231 further includes an index table. The index table
defines a correspondence between titles constituting the
content and movie objects or BD-J objects.
Fig. 3 is a schematic diagram showing the index table
310 in the index file 231. The index table 310 stores items
such as a first play 301, a top menu 302, and a title k 303 (k
= 1, 2, ..., n; an integer n is equal to or greater than one) .
Each item is assigned to one of movie objects MVO-2D, MVO-3D,
..., and BD-J objects BDJO-2D, BDJO-3D, ... On the other hand, the
items are assigned to various events by the control unit of the
playback device 110. The "events" include, for example,
insertion/removal of a disc into/from the BD-ROM drive 111,
operation of the remote control 14 0 by the user, and requests
issued from application programs. Each time an event occurs,
the control unit of the playback device 110 refers to the index
19

table 310, and calls an object specified by an item
corresponding to the event, from the BD-ROM disc 100. The
control unit further performs various processes in accordance
with the called object.
The "first play" 301 specifies an object to be called
when the disc 100 is loaded into the BD-ROM drive 111. The
object causes the playback device 110 to, for example, execute
the process for displaying a warning message to viewers and the
logo of the content provider. The "top menu" 3 02 specifies an
object for displaying a menu on the display device 120 when a
command "go back to menu" is input, for example, by user
operation. The object causes the playback device 110 to execute
the process for displaying a menu. In the "title k" 303 , objects
are individually allocated to titles that constitute the
content body on the disc 100. One of the objects is called when
a title for playback is specified by user operation, and the
called object causes the playback device 110 to execute the
process for playing back an AV stream file belonging to the
title.
In the example in Fig. 3, the movie object assigned to
the item "title 1" and the item "title 2" are both allocated
as 2D video image titles. The first movie object MV0-2D
corresponding to the item "title 1" includes a group of
instructions related to playback processes for 2D video images
using the first playlist file 233A. When the playback device
110 refers to the item "title 1," then in accordance with the
instructions in the movie object MVO-2D, the first playlist file
233A is read from the disc 100, and playback processes for 2D
video images are executed in accordance with the playback path
specified in the read file. On the other hand, the first BD-J

object BDJ0-2D assigned to the item "title 2 specifies an
application program related to playback processes for 2D video
images using the first playlist file 233A. When the playback
device 110 refers to the item "title 2", the application program
is executed in accordance with the first BD-J object BDJO-2D.
Thus, the first playlist file 233A is read from the disc 100,
and playback processes for 2D video images are executed in
accordance with the playback path specified in the read file.
In the example in Fig. 3, the items "title 3" and "title
4" are allocated to 3D video image titles. The second movie
object MV0-3D assigned to the item "title 3" contains, in
addition to a group of instructions related to 2D image playback
process using the first playlist file 233A, a group of
instructions related to 3D image playback process using the
playlist file 233B. The second BD-J object BDJ0-3D assigned
to the item "title 4" specifies, in addition to an application
program related to 2D image playback process using the first
playlist file 233A, an application program related to 3D image
playback process using the playlist file 233B. For example,
when the title 3 is selected by user operation, the playback
device 110 refers to the item "title 3" in the index table 310,
and calls the second movie object MVO-3D. After that, the
playback device 110 first performs the following three types
of distinguishing processes: 1) Does the playback device 110
itself support playback of 3D video images? 2) Has the user
selected 3D video image playback? and 3) Does the display device
12 0 support playback of 3D video images? Next, the playback
device 110 selects one of the playlist files 233A-B in
accordance with the results of the above-described
distinguishing processes, and executes the 3D image playback

process in accordance with the playback path specified in the
selected file. When, on the other hand, the playback device
110 refers to the item "title 4" and calls the second BD-J object
BDJO-3D, the playback device 110 executes a variety of
application programs in accordance with the second BD-J object
BDJ0-3D. In this way, the playback device 110 executes the
distinguishing processes, the process of selecting a playlist
file in accordance with the results thereof, and the process
of playing back the 3D video image in accordance with the
playback path specified in the selected playlist file.
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The movie object file 232 generally stores a plurality
of movie objects. Each movie object stores a sequence of
navigation commands . A navigation command is a control command
causing the playback device to execute playback processes
similarly to general DVD players . Types of navigation commands
include, for example, a read command to read a playlist file
corresponding to a title, a playback command to play back an
AV stream file indicated by a playlist file, and a transition
command to make a transition to another title. Navigation
commands are written in an interpreter-type language and are
interpreted by an interpreter, namely, a job control program,
embedded in the playback device to make the control unit execute
the desired job. A navigation command is composed of an opcode
and an operand. The opcode describes the operation that the
playback device is to execute, such as causing the title to
branch, playing back the title, or calculating. The operand
indicates identification information of a subject of the
operation, such as the number of the title. The control unit
of the playback device 110 calls a movie object in response,

for example, to a user operation and executes navigation
commands included in the called movie object in the order of
the sequence . Thus, in a manner similar to general DVD players,
the playback device 110 first causes the display device 12 0 to
display a menu and allows the user to select a command. The
playback device 110 then executes playback start/stop of a title,
switches to another title, etc. in accordance with the selected
command, thereby dynamically changing the progress of video
playback. Note that the operation mode of the playback device
110 conforming to the movie object is called the HDMV (High
Definition Movie) mode.
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In the BD-J object files 236A and 236B, BD-J objects
are written in a compiler-type language such as Java. The
control unit of the playback device 110 calls a BD-J object in
response to a user operation or a request from the application
program. The BD-J object is interpreted by the Java platform
implemented in the control unit. The control unit further
causes the Java virtual machine to execute a variety of
application programs in accordance with the BD-J obj ect. Thus,
the playback device 110 dynamically changes the progress of
title video playback, or causes the display device 12 0 to
display the graphics image independently of the title video
image. Note that the operation mode of the playback device 110
conforming to the BD-J object is called the BD-J mode.
Figs. 4A and 4B are schematic diagrams showing images
displayed on the screen 121 of the display device 120 in the
HDMV mode and the BD-J mode, respectively. Fig. 4A shows one
scene of a video image played back in the HDMV mode. In the
HDMV mode, the video images of the content body, such as the

main plot of the movie, recorded on the BD-ROM disc 100 is
displayed on the entirety of the screen 121, like video images
to be played back from a DVD. On the other hand, Fig. 4B shows
one scene of video images played back in the BD-J mode. In the
BD-J mode, it is possible to cause the Java virtual machine in
the playback device 110 to render graphics images in
synchronization with the video images of the content body. For
example, as shown in Fig. 4B, the images SCN of the main plot
of the movie, the title TL of the movie, an animated image CR
of an owl that comments on the movie, a background image BG,
and a pop-up menu PPM can be displayed simultaneously in one
screen of the screen 121.
In the BD-J mode, the BD-Live functions are further
available. With the BD-Live functions, the application
program can cause the playback device 110 to download additional
contents such as subtitles, and interactive contents such as
browser screens, from the server device 160 on the external
network 150. The application program can further cause the
playback device 110 to display the downloaded contents together
with the images of the content body recorded on the BD-ROM disc
100, as shown in Fig. 4B.
In the BD-J mode, when both the playback device 110 and
the display device 12 0 support display of 3D video images, it
is possible to cause the Java virtual machine to render graphics
images as 3D video images together with the video images of the
content body. The process for playing back graphics images as
3D video images has two types of modes: a 2-plane mode and an
offset mode. In the "2-plane mode", left-view image data and
right-view image data are separately prepared, as is the case
with the video streams of the content body, and then left-view

image planes and right-view image planes are separately
rendered by the Java virtual machine. In the "offset mode",
the playback device 110 generates pairs of a left-view image
plane and a right-view image plane from usual image data
representing 2D video images.
Figs. 5A through 5D are schematic diagrams showing an
example of generating a left view 502L and a right view 502R
from 2D video images 501 in the offset mode. With reference
to Fig. 5A, the 2D video images 501 include a circular plate
511 and subtitles 513 in a background 512. The playback device
110 processes the image data representing the 2D video images
501 to shift the display positions of elements of the 2D video
images 501 horizontally. Thus, the left view 502L and the right
view 502R are generated from the 2D video images 501. In the
example shown in Figs. 5B and 5C, the display positions of the
circular plate 521L in the left view 502L and the circular plate
521R in the right view 502R have been shifted to the right and
the left, respectively, by an offset value SI from the display
position of the circular plate 511 in the 2D video images 501.
Similarly, the display positions of the subtitles 523L in the
left view 502L and the subtitles 523R in the right view 502R
have been shifted to the right and the left, respectively, by
an offset value S3 from the display position of the subtitles
513 in the 2D video images 501. In this case, a viewer sees
both the circular plate 531 and the subtitles 533 in front of
a screen 503 as shown in Fig. 5D. On the other hand, the display
positions of the background 522L in the left view 502L and the
background 522R in the right view 5 02R have been shifted to the
left and the right, respectively, by an offset value S2 from
the display position of the background 512 in the 2D video images

501. In this case, the viewer sees the background 532 behind
the screen 503.
Fig. 6A is a schematic diagram showing the data
structure of a BD-J object. With reference to Fig. 6A, the BD-J
object includes an application management table 610 and an image
playback state value 62 0.
The application management table 610 is a list of
application programs to be executed and the timing of execution
thereof, namely, life cycles thereof. With reference to Fig.
6A, the application management table 610 includes a plurality
of combinations of an application identifier 611, a control code
612, and application detailed information 613. The
application identifier 611 indicates a file name of a JAR file
including an application program to be executed. The control
code 612 indicates an activation mode of the application program
identified by the application identifier 611. There are two
types of activation modes : Auto Start and Present. "Auto Start"
indicates that the application program is automatically
activated at the start of playback of the title. "Present"
indicates that the application program is activated in response
to a call from another application program. The application
detailed information 613 includes an application name 631,
binding information 632, and an icon locator 633. The
application name 631 indicates the name of the application
program to be executed. The binding information 632 indicates
a life cycle of the application program identified by the
application name 631. There are three types of life cycles:
title-bound, disc-bound, and disc-unbound. "Title-bound"
indicates that the execution period of the application program
is limited to a period of one title. "Disc-bound" indicates

that the execution period of the application program is limited
to a period until the BD-ROM disc is removed from the BD-ROM
drive, but not limited to the period of any title contained in
the BD-ROM disc. "Disc-unbound" indicates that the execution
period of the application program continues after the BD-ROM
disc is removed from the BD-ROM drive. The icon locator 633
indicates an address of an icon data in a JAR file; the icon
data is to be associated with the application program identified
by the application name 631.
Fig. 6B is a schematic diagram showing life cycles of
six types of application programs A1-A5 and All. With reference
to Fig. 6B, the playback device 110 plays back a first title
TL1 from a first disc D1 during the period from time T1 to time
T2, and then plays back a second title TL2 during the period
from time T2 to time T3 . At time T3, the first disc Dl is removed
from the playback device 110. After that, when a second disc
D2 is inserted into the playback device 110 at time T4, the
playback device 110 plays back a third title TL3 from the second
disc D2 during the period from time T4 . Title-bound application
programs A1, A2, and A3 are executed during the playback periods
of the titles TL1, TL2, and TL3, respectively. Since the
activation modes of all the application programs Al, A2, and
A3 are Auto Start, the life cycles of the application programs
Al, A2, and A3 match the playback periods of the titles TL1,
TL2, and TL3, respectively. During the playback period T1-T2
of the first title TL1, another title-bound application program
All is executed as well. Since the activation mode of the
application program All is Present, the application program All
is activated in response to a call from the Auto start
application program Al executed in the same period. On the

other hand, since the application program All is title-bound,
the application program All is terminated at the end of the
playback period of the first title TL1. During the period T1-T3
for which the first disc D1 is kept inserted in the playback
device 110, a disc-bound application program A4 is executed as
well. The application program A4 continues to be executed even
after the first title TL1 is changed to the second title TL2
at time T2 . Since the application program A4 is disc-bound,
the application program A4 is terminated when the first disc
Dl is removed from the playback device 110 at time T3 . During
the periods from time T1 to time T4 and after time T4, a
disc-unbound application program A5 is executed. The
application program A5 continues to be executed after the first
disc Dl is removed from the playback device 110 at time T3 and
after the second disc D2 is inserted into the playback device
110 at time T4.
The image playback state value 620 indicates a state
of the playback device 110 with respect to playback processes
of image data; the state is to be realized in the playback period
of the title assigned to the BD-J object. The control unit of
the playback device 110, when calling the BD-J object, changes
the state of the playback device 110 such as allocation of memory
areas in accordance with the image playback state value 62 0
presented by the BD-J object. There are four types of states
of the playback device 110 with respect to playback processes
of image data; States 1 through 4. In order to indicate each
of the states, the image playback state value 62 0 can take one
of four integers, 0 through 3. When the image playback state
value 62 0 is equal to 0, 1, 2, and 3, the state of the playback
device 110 is set to State 1, State 2, State 3, and State 4,

respectively, during the playback period of the title,
Fig. 7 is a state transition diagram showing States 1-4 .
With reference to Fig. 7, in States 1-4, application programs
are permitted to use or prohibited from using different
combinations of the offset mode, the 2-plane mode, and the
BD-Live function.
In State 1, the playback process of 3D video images
itself is disabled, and thus image data can be played back only
as 2D images. That is to say, both the offset mode and the
2-plane mode are disabled. On the other hand, the BD-Live
function is enabled.
In State 2, the playback process of 3D video images from
video streams is enabled. However, with respect to the playback
process of 3D video images from image data, the 2-plane mode
is disabled, and only the offset mode is enabled. On the other
hand, the BD-Live function is enabled.
In State 3 , the playback process of 3D video images from
video streams is enabled. In addition, with respect to the
playback process of 3D video images from image data, both the
2-plane mode and the offset mode are enabled. On the other hand,
the BD-Live function is enabled with a more restricted cache
area for holding image data such as browser screens.
In State 4, as in State 3, the playback process of 3D
video images from video streams, and in addition, the playback
process of 3D video images from image data in either of the
2-plane mode and the offset mode are enabled. However, in
contrast to State 3, the BD-Live function is disabled.
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Fig. 8 is a schematic diagram showing the data structure
of the JAR file 237A. The JAR file 237A is a Java archive file.

Java archive files are zip files specialized in Java to conform
to the specifications recited in "http://java.sun.com/j2se/
1.4.2/docs/guide/jar/ jar.html." Accordingly, the contents
of Java archive files can be confirmed by commercially available
zip decompression software. The JAR file 237A contains a
compressed directory/file group 800 having a structure shown
in Fig. 8. The directory/file group 800 is decompressed by the
Java virtual machine from the JAR file 237A into a heap area
(also called work memory) in the Java virtual machine. In the
directory/file group 800, a classes directory 810 and an image
directory 82 0 are placed immediately below the ROOT directory
801.
The classes directory 810 includes a class file
("aaa. class") 811. The class file 811 includes an xlet program.
The xlet program is a body of an application program, and its
name is recited in the application management table 610 in the
BD-J object. The xlet program is, like the BD-J object, a
bytecode program written in a compiler language such as the Java
language . Xlet programs include a type causing the Java virtual
machine to execute the playback process of a title, and another
type causing the Java virtual machine to execute the rendering
process of graphics video images.
The image directory 820 includes image data to be used
for GUI by application programs . The image data includes a JPEG
file ("menu.jpg") 821 and a PNG file ("menu.png") 822. The
image data represents graphic elements for GUI such as menus,
and is equivalent to those used in the European Digital Video
Broadcasting-Multimedia Home Platform (DVB-MHP) terminals.
The image data especially includes image data that represents
the left view and right view of graphic elements.

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The AV stream files 235A and 235B are digital streams
in the MPEG-2 transport stream (TS) format. In each of the AV
stream files 235A and 235B, a plurality of elementary streams
are multiplexed. Fig. 9A is a schematic diagram showing the
elementary streams multiplexed in the first AV stream file 235A,
and Fig. 9B is a schematic diagram showing the elementary
streams multiplexed in the second AV stream file 235B. With
reference to Figs. 9A and 9B, the first AV stream file 235A
includes a left-view video stream 901L, primary audio streams
902Aand902B, presentation graphics (PG) streams 903A and 903B,
an interactive graphics (IG) stream 904, a secondary audio
stream 905, and a secondary video stream 906 . On the other hand,
the second AV stream file 235B includes a right-view video
stream 901R.
The left-view video stream 901L and the right-view video
stream 901R are primary video streams, and respectively
represent the left views and the right views of the main images
of the movie. The main images mean the images representing the
essential portions of the content, such as the main plot of the
movie, and in the HDMV mode, it indicates an image that is
displayed on the entire screen. On the other hand, the
secondary video stream 906 represents the sub-images of the
movie. The sub-images mean the images displayed on the screen
together with the main images by using Picture-in-Picture
effect, such as an image displayed in a small screen within the
main images. Each video stream has been encoded by a video
compression encoding method such as MPEG-2, MPEG-4, AVC, or
SMPTE VC-1. Especially, the left-view video stream 901L has
been compressed by the inter-picture predictive encoding

between pictures of itself. On the other hand, the right-view
video stream 901R has been compressed by the inter-picture
predictive encoding between pictures of the left-view video
stream 901L and pictures of itself, as well as between pictures
of itself.
The primary audio streams 902A and 902B represent
primary audios of the movie. The primary audio streams 902A
and 902B differ in the language or the audio output format. The
secondary audio stream 905 represents a sub-audio to be mixed
with the main audio. Each audio stream has been encoded by an
encoding method such as AC-3, Dolby Digital Plus ("Dolby
Digital" is a trademark), MLP, DTS (Digital Theater System,
which is a trademark), DTS-HD, or linear PCM (Pulse Code
Modulation).
The PG streams 903A and 903B represent graphics images
of subtitles of the movie. The PG streams 903A and 903B in the
language for subtitle. The IG stream 904 represents graphic
elements for GUI and their respective locations. The IG stream
904 is mainly used to display an interactive screen on the screen
131 of the display device 12 0 in the HDMV mode.
The elementary streams 901-906 are identified by the
packet ID (PID). For example, a hexadecimal value "0x1011" is
assigned to the left-view video stream 901L as the PID, and a
hexadecimal value "0x1012" is assigned to the right-view video
stream 901R as the PID. Any two values in the range from
"0x1100" to "OxlllF" are respectively assigned to the primary
audio streams 902A and 902B as the PIDs. Any two values in the
range from "0x1200" to "0xl21F" are respectively assigned to
the PG streams 903A and 903B as the PIDs. Any value in the range
from "0x1400" to "0xl41F" is assigned to the IG stream 904 as

the PID. Any two values in the range from "0x1200" to "0x12IF"
are respectively assigned to the PG streams 903A and 903B as
the PIDs. Any value in the range from "0x1B00" to "Ox1BlF" is
assigned to the secondary video stream 906 as the PID. Any value
in the range from "0x1A00" to "0x1A1F" is assigned to the
secondary audio stream 905 as the PID.
Fig. 10 is a schematic diagram showing the arrangement
of the packets of the elementary streams 1001, 1004, 1007, and
1010 multiplexed in the first AV stream file 235A. This
arrangement also applies to the second AV stream file 235B. The
video stream 1001, the audio stream 1004, the PG stream 1007,
and the IG stream 1010 are first converted to PES (Packetized
Elementary Stream) packet sequences 1002, 1005, 1008, and 1011
respectively, and then converted to TS packet sequences 1003,
1006, 1009, and 1012 respectively. After that, a header is
attached to each TS packet individually. Thus, source packets
1013 are generated. Finally, the source packets 1013 are
multiplexed into one stream by the time division. In this way,
the first AV stream file 235A is structured. Note that, as shown
in Fig. 10, in the first AV stream file 235A, the source packets
1013 are assigned with serial numbers in the order from the top
one. The serial numbers are called source packet numbers (SPNs) .
The SPNs are used as the addresses of the source packets 1013
in the first AV stream file 235A.
For example, from the video stream 1001, the TS packet
sequence 1003 is obtained as follows. First, a sequence of
video frames 1001A constituting the video stream 1001 is
converted to a sequence of PES packets 10 02 . It should be noted
here that each video frame 1001A has been encoded as one picture
by the above-mentioned video compression encoding method.

Furthermore, the sequence of video frames 10 01A has been divided
into a plurality of GOPs (Groups Of Pictures) . Each PES packet
1002 includes a PES header and a PES payload. Each video frame
1001A is compressed as one picture by the above-mentioned video
compression encoding method, and is stored into each PES payload.
On the other hand, in each PES header, the display time (PTS:
Presentation Time Stamp) of the picture that is stored in the
PES payload of the same PES packet is stored. The PTS indicates
a time at which one frame of data, which is decoded from one
elementary stream by a decoder in the playback device 110, is
output from the decoder. Next, generally, each PES packet 1002
is converted into a plurality of TS packets 1003 . Each TS packet
1003 is a packet having a fixed length, and includes a TS header
and a TS payload. The TS header includes a PID of a video stream
stored in the corresponding TS payload. Each PES packet is
divided into a plurality of pieces, and they are respectively
stored in a plurality of TS payloads. This structure of the
TS packet also applies to the other elementary streams.
The types of the TS packets contained in the AV stream
file include not only those that are converted from the
elementary streams shown in Figs. 9A and 9B, but also a PAT
(Program Association Table) , a PMT (Program Map Table) , and a
PCR (Program Clock Reference) . The PCR, PMT, and PAT are
defined in European Digital Broadcasting Standard and are
intended to specify the partial transport stream constituting
a single broadcast program. By using PCR, PMT, and PAT, the
AV stream file can be specified in the same way as the partial
transport stream. More specifically, the PAT indicates the PID
of a PMT included in the same AV stream file. The PID of the
PAT itself is 0. The PMT includes the PIDs for the elementary

streams representing video, audio, subtitles, etc. included in
the same AV stream file, as well as the attribute information
of the elementary streams. The attribute information includes
the identification information of the codec used in compressing
the elementary stream, and includes the frame rate and aspect
ratio of the elementary stream. The PMT also includes various
descriptors relating to the AV stream file. The descriptors
particularly include copy control information showing whether
copying of the AV stream file is permitted or not. The PCR
stores information indicating the value of an STC (System Time
Clock) to be associated with an ATS of the packet. Here, the
STC is a clock used as a reference for the PTS and the DTS in
a decoder. With the use of PCR, the decoder synchronizes the
STC with the ATC (Arrival Time Clock) that is the reference for
the ATS . By using PCR, PMT, and PAT, the decoder in the playback
device can be made to process the AV stream file in the same
way as the partial transport stream conforming to the European
Digital Broadcasting Standard. This makes it possible to
ensure compatibility between a playback device for the BD-ROM
disc 100 and a terminal device conforming to the European
Digital Broadcasting Standard.
In an AV stream file, a portion that can be played back
seamlessly is called "AV clip". The seamless playback of each
AV clip over the entire display time is ensured because, for
one thing, PTSs of data stored in the source packets are
continuous.
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Fig. 11 is a schematic diagram showing the data
structure of the first clip information file (01000. clpi) 234A.
As shown in Fig. 11, the first clip information file 234A

includes stream attribute information 1101, an entry map 1102,
and 3D metadata 1103. On the other hand, second clip
information file 234B has the same data structure as the first
clip information file 234A except for the 3D metadata 1103.
As shown in Fig. 11, the stream attribute information
1101 is a correspondence table associating the PIDs 1111 for
each elementary stream included in the first AV stream file 235A
with pieces of attribute information 1112. Here, each piece
of attribute information 1112 is different depending on whether
it corresponds to a video stream, an audio stream, a PG stream,
or an IG stream. For example, the piece of attribute
information corresponding to the PID 0x1011 for the left-view
video stream includes a codec type used for the compression of
the video stream, as well as a resolution, an aspect ratio, and
a frame rate for the pictures constituting the video stream.
On the other hand, the piece of attribute information
corresponding to the PID 0x1101 for the primary audio stream
includes a codec type used for compressing the audio stream,
the number of channels included in the audio stream, a language,
and a sampling frequency. The playback device 110 uses these
pieces of attribute information 1112 to initialize the decoder.
The right-view stream in the second AV stream file 235B
has been compressed by using the left-view stream in the first
AV stream file 235A. Therefore, the right-view stream has the
same video stream attributes as the left-view stream. That is
to say, the piece of attribute information corresponding to the
right-view video stream (PID=Oxl012) includes the same codec
type, resolution, aspect ratio, and frame rate as the piece of
attribute information corresponding to the left-view video
stream (PID=0xl011) in the first clip information file 234A.

As shown in Fig. 11, the entry map 1102 includes tables
1121 which are respectively assigned to video streams in the
first AV stream file 23 5A. Each table 1121 corresponds to the
PID for the assigned video stream. Each table 1121 includes
a plurality of entry points 1122. Each entry point 1122 is
composed of a pair of PTS and SPN. The PTS is equivalent to
the PTS for the top picture (I picture) of any GOP included in
the assigned video stream. On the other hand, the SPN paired
with the PTS in the same entry point 1122 is equivalent to the
top SPN of the source packet group in which that I picture is
stored. With reference to the entry map 1102, the playback
device 110 can specify the SPN within the first AV stream file
23 5A corresponding to a scene at an arbitrary point during the
playback of the video from the video stream. Especially, to
execute trickplay such as fast-forward or rewind, the playback
device 110 selectively extracts and decodes source packets with
reference to the SPNs in each entry point 1122. As a result,
the I picture can be selectively played back. Thus, the
playback device 110 can efficiently process trickplays without
analyzing the first AV stream file 235A itself.
The second clip information file 234B has a similar
structure as the first clip information file 234A. That is to
say, the entry map includes a plurality of entry points for the
right-view video stream. Each entry point is composed of a pair
of PTS and SPN. The PTS is equivalent to the PTS for the top
picture (P picture) of any GOP included in the right-view video
stream. On the other hand, the SPN paired with the PTS in the
same entry point is equivalent to the top SPN of the source packet
group in which that P picture is stored. The PTS in each entry
point is further equivalent to the PTS in each entry point for

the left-view stream indicated by the first clip information
file 234A. That is to say, in a pair of corresponding left-view
and right-view video streams, whenever an entry point is set
in one of a pair of pictures that represent the same scene in
the 3D image, an entry point is set in the other of the same
pair of pictures. As a result, when the playback device begins
an interrupt playback of a 3D video image, it can immediately
acquire the top SPN of the source packet group to be played back
from the corresponding entry point. In this way, even during
playback of 3D video images, it is possible to improve response
speed for processes, such as the interrupt playback, that
require random access to the video stream.
Fig. 12 is a schematic diagram showing the data
structure of the 3D metadata 1103. The 3D metadata 1103 is
information used for the cropping processes on the PG stream
903A and 903B, and IG stream 904 that are multiplexed in the
first AV stream file 235A shown in Fig. 9. The "cropping
process" refers to a process that adds depth to the 2D video
images played back from each stream. During the cropping process,
a pair of a left view and a right view is generated by shifting
each 2D video image in a horizontal direction. The amount of
shifting corresponds to the binocular parallax that generates
the depth that should be given to that 2D video image. In
particular, the 3D metadata 1103 includes an "offset value"
which is a value that represents the amount of shifting by the
number of pixels.
As shown in Fig. 12, the 3D metadata 1103 includes a
table 1201 for each of (i) PID=0xl200 for the PG stream 903A
and (ii) PID=0xl400 for the IG stream 904. Each table 1201
generally includes a plurality of pairs of PTS 12 02 and offset

value 1203, namely a plurality of offset entries 1204. The PTS
1202 is equivalent to the PTS of one picture that is included
in the PG stream 903A and the IG stream 904. The offset value
1203 represents the offset value for the picture to which the
PTS 1202 is allocated. The offset values 1203 may be negative
values. The valid section of each offset entry 1204 ranges from
the PTS of the offset entry to the PTS of the subsequent offset
entry. In the example in Fig. 12, the PTS of the first offset
entry is 180000, the PTS of the second offset entry is 270000,
and the PTS of the third offset entry is 360000. In this case,
an offset value "+5" in the first offset entry is valid in an
STC range from 180000 to 270000, and an offset value "+3" in
the second offset entry is valid in an STC range from 270000
to 360000.
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Fig. 13 is a schematic diagram showing the data
structure of the second playlist file 233B. With reference to
Fig. 13, the second playlist file 233B includes playlist
information 1301. The playlist information 1301 includes main
path information 1310 and sub-path information 1320 and 1330.
The main path information 1310 includes at least one piece of
playitem information, and in this example, includes playitem
information 1311, 1312, 1313, ... Each of the playitem
information 1311-1313 defines playback sections of the first
AV stream file 235A, namely, portions to be played back
continuously. The playitem information 1311-1313 are further
assigned with serial numbers #1, #2, #3, ... in the playback order
of the playback sections. The sub-path information 1320 and
1330 are respectively assigned with unique identifiers, namely
sub-path IDs "#1" and "#2" . The sub-path information 1320 with

sub-path ID=#1 includes at least one piece of sub-playitem
information, and in this example, includes sub-playitem
information 1321, 1322, 1323, ... Each of the sub-playitem
information "1321-1323 defines playback sections of the second
AV stream file 235B. The sub-playitem information 1321-1323
are further assigned with serial numbers #1, #2, #3, ... in the
playback order of the playback sections. The sub-path
information 1330 with sub-path ID=#2 includes at least one piece
of sub-playitem information, and in this example, includes
sub-playitem information 1331, 1332, 1333, ... Each of the
sub-playitem information 1331-1333 defines other playback
sections of both the first AV stream file 235A and the second
AV stream file 235B, or defines playback sections of another
AV stream file that is different from the stream files 235A and
235B. The sub-playitem information 1331-1333 are further
assigned with serial numbers #1, #2, #3, ... in the playback order
of the playback sections.
Fig. 14 is a schematic diagram showing the data
structure of the playitem information 1400. With reference to
Fig. 14, the playitem information 1400 includes reference clip
information 14 01, a playback start time 14 02, a playback end
time 14 03 , and a stream selection table 14 04 . It should be noted
here that the sub-playitem information has the same data
structure as the playitem information, except for the stream
selection table.
The reference clip information 1401 is information for
identifying a clip information file that is to be used for
converting PTSs to SPNs. The playback start time 1402 and the
playback end time 1403 respectively indicate the PTSs of the
top and the end of the section of the AV stream file to be decoded.

The playback device 110 refers to the entry map from the clip
information file indicated by the reference clip information
14 01, and obtains SPNs respectively corresponding to the
playback start time 1402 and the playback end time 1403. From
the obtained SPNs, the playback device 110 identifies the AV
clip that is to be read from the AV stream file and starts to
play back the AV clip.
The stream selection table 14 04 shows a list of
elementary streams that the decoder in the playback device 110
can select from the AV stream file during the time between the
playback start time 1402 and the playback end time 1403. The
stream selection table 14 04 particularly includes a plurality
of stream entries 1410, 1420, ... Each of the stream entriesl410,
1420, ... includes a stream selection number 1411, stream path
information 1412, and stream identification information 1413.
The stream identification information 1413 indicates the PID
of a corresponding one of the elementary streams that can be
selected during the time between the playback start time 14 02
and the playback end time 14 03 . The stream selection number
1411 is a serial number assigned to the stream entry 1410, and
used by the playback device 110 to identify elementary streams
to be selected. Each piece of stream path information 1412
shows a clip information file assigned to an AV stream file to
which an elementary stream specified by the stream
identification information 1413 belongs. For example, if the
stream path information 1412 shows "main path," the
corresponding clip information file is indicated by the
reference clip information 1401. If the stream path
information 1412 shows "sub-path ID=#1, the corresponding clip
information file is indicated by the reference clip information

of a piece of sub-playitem information included in the sub-path
information whose sub-path ID=#1. Here, the piece of
sub-playitem information defines a playback section included
between the playback start time 14 02 and the playback end time
1403. Especially, since the second playlist file 233B is a 3D
playlist file, the playitem information thereof includes,
without fail, (i) the stream entry 1410 that indicates
PID=0xl011 of the left-view video stream and (ii) the stream
entry 1420 that indicates PID=0xl012 of the right-view video
stream. Note that, although not shown in Fig. 14, each of the
stream entries 1410 and 1420 stores attribute information of
each elementary stream. For example, the attribute
information of the video stream indicates the resolution and
the frame rate, and the attribute information of the audio
stream, PG stream, and IG stream indicates a language type.
Fig. 15 is a schematic diagram showing the playlist
information 1301 shown in Fig. 13 and the AV clips CL1, CL2,
and CL4 that are to be played back in accordance with the playlist
information 1301. The three time axes MP, SP1 and SP2 shown
in Fig. 15 respectively represent playback times of the video
streams that are respectively played back in accordance with
the main path information 1310, the sub-path information #1 1320,
and the sub-path information #2 1330.
In the playback process in accordance with the playlist
information 1301, first the playitem information 1311-1313 are
referenced in the order of the serial numbers #1 to #3. For
example, when the playitem information #1 1311 is referenced,
from the entry map of the first clip information file 234A
indicated by the reference clip information 14 01 thereof, an
entry point including a PTS that is equivalent to the playback

start time IN1 is detected. Then the SPN of the entry point
is identified as the start address SP1. Similarly, an entry
point including a PTS that is equivalent to the playback end
time 0UT1 is detected, and the SPN of the entry point is
identified as the end address EP1. In this way, in the playback
section PI1 ranging from the playback start time IN1 to the
playback end time 0UT1, the portion ranging of the first AV
stream file 235A from the start address SP1 to the end address
EP1, namely the first AV clip CL1 is identified as the subject
to be played back. Following this, by using the stream
attribute information 1101 of the first clip information file
234A, elementary streams that can be played back by both the
playback device 110 and the display device 120 are detected from
among the elementary streams recorded in the stream selection
table 1404 of the playitem information #1 1311. Then, an
elementary stream having the smallest value of the stream
selection number 1411 is selected from among the detected
elementary streams, and the PID described in the stream
identification information 1413 in the stream entry 1410
indicated by the stream selection number 1411 is set in the
decoder in the playback device 110. As a result of this, a
source packet with the set PID in the first AV clip CL1 is decoded
by the decoder. Similarly, playitem information #2 1312, #3
1313, ... are referenced in the stated order, and the source
packets are decoded from the AV clip belonging to the first AV
stream file 235A, in the playback sections P12, P13, ... each
from the playback start time to the playback end time.
In the stream selection table 14 04 in each of the
playitem information 1311-1313 , the stream entry 1420 including
PID=0xl012 of the right-view video stream indicates "sub-path

ID=#1" as the stream path information. This enables the
playback device 110 to reference the sub-play item information
1321-1323 in the sub-path information 1320 in the order of the
serial numbers #1-#3, in parallel with the playback process in
accordance with the main path information 1310. It should be
noted here that the sub-play item information 1321-1323
correspond to the playitem information 1311-1313 on a
one-to-one basis. Furthermore, the sub-play item information
1321-1323 and the corresponding playitem information 1311-1313
have the playback start time and the playback end time in common.
For example, when the sub-playitem information 1321 is to be
referenced, first an entry point including a PTS equivalent to
the playback start time IN1 is detected from the entry map of
the second clip information file 234B indicated by the reference
clip information thereof. Next, the SPN of the entry point is
identified as the start address SP2. Similarly, the SPN of an
entry point including the PTS equivalent to the playback end
time OUT1 is identified as the end address EP2 . In this way,
in the playback section PI1 ranging from the playback start time
INI to the playback end time OUT1, the portion of the second
AV stream file 235B ranging from the start address SP2 to the
end address EP2, namely the second AV clip CL2 is identified
as the subject to be played back. Following this, by using the
stream attribute information of the second clip information
file 234B, elementary streams that can be played back by both
the playback device 110 and the display device 120 are detected
from among the elementary streams recorded in the stream
selection table 1404 of the playitem information #1 1311. Then,
an elementary stream having the smallest value of the stream
selection number is selected from among the detected elementary

streams, and the PID described in the stream identification
information in the stream entry indicated by the stream
selection number is set in the decoder in the playback device
110. As a result of this, a source packet with the set PID in
the second AV clip CL2 is decoded by the decoder. It should
be noted here that the decoding process is performed in parallel
with the decoding process of the source packet from the first
AV clip CL1. Similarly, sub-playitem information #2 1322, #3
1323,... are referenced in the stated order, and the source
packets are decoded from the AV clip belonging to the second
AV stream file 235B, in correspondence with the playback
sections P12, P13, ...
When the stream selection table 14 04 of the playitem
information 1311 includes a stream entry that indicates
"sub-path ID=#2" as the stream path information, the
sub-playitem information #1 1331 included in the sub-path
information #2 1330 is referenced. Here, the sub-playitem
information #1 1331 is detected based on the condition:
"playback section SPI4 from the playback start time IN4 to the
playback end time OUT4 is included in the playback section PI1
of the playitem information #1" . Next, in a similar manner in
which the first AV clip CL1 is identified from the playback
section PI1 of the playitem information #1 1311, the start
address SP4 and the end address EP4 of the fourth AV clip CL4
are identified from the playback section SPI4 of the
sub-playitem information #1 1331. Thus, in the playback
section SPI4 of the sub-playitem information #1 1331, a source
packet is decoded from the fourth AV clip CL4, as well as from
the first AV clip CL1 and the second AV clip CL2.
As described above, in the second playlist file 233B,

the main path information 1310 defines the playback path of the
first AV stream file 235A as a permutation of the playitem
information 1311-1313, and the sub-path information 1320
defines the playback path of the second AV stream file 235B as
a permutation of the sub-playitem information 1321-1323. In
this way, the 3D playlist file defines the playback paths of
the AV stream files for the left view and the right view, by
the combination of the main path information and the sub-path
information. The playlist file may further include the
sub-path information such as the sub-path information 1330
shown in Fig. 13. The sub-path information defines another
playback path of the AV stream file that is to be played back
in correspondence with the playback path of the AV stream file
defined by the main path information 1310, or defines a playback
path of another AV stream file. Note that the first playlist
file 233A has a similar data structure to the second playlist
file 233B, except that it does not include the sub-path
information defining the playback path of the right-view AV
stream file.
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Fig. 16 is a block diagram showing the hardware
structure of the playback device 110. As shown in Fig. 16, the
playback device 110 includes a BD-ROM drive 111, a local storage
1610, a card reader/writer 1611, an operation unit 1620, a
network interface 1630, a bus 1640, a control unit 1650, a
playback unit 1660, and an HDMI transmission unit 1670. The
BD-ROM drive 111, local storage 1610, operation unit 1620, and
network interface 163 0 can communicate with the control unit
1650 and the playback unit 1660 via the bus 1640. Also, the
control unit 1650 and the playback unit 1660 can communicate

with each other via the bus 1640. The control unit 1650 and
the playback unit 1660 are implemented on different integrated
circuits, respectively. Not limited to this, however, the
control unit 1650 and the playback unit 1660 may be implemented
on the same single integrated circuit.
The BD-ROM disc 100 can be loaded into the BD-ROM drive
111. While the BD-ROM disc 100 is loaded in the BD-ROM drive
111, the BD-ROM drive 111 reads data from the BD-ROM disc 100
in accordance with an instruction from the control unit 1650.
More specifically, the BD-ROM drive 111 is equipped with an
optical pickup, namely an optical head. The optical head has
a semiconductor laser, a collimate lens, a beam splitter, an
objective lens, a collecting lens, and an optical detector. A
beam of light radiated from the semiconductor laser
sequentially passes through the collimate lens, the beam
splitter, and the objective lens to be collected on a recording
layer of the BD-ROM disc 100. The collected beam is reflected
and diffracted by the recording layer. The reflected and
diffracted light passes the objective lens, the beam splitter,
and the collecting lens to be collected onto the optical
detector. The optical detector generates a playback signal at
a level in accordance with the amount of the collected light.
Furthermore, data recorded on the BD-ROM disc 100 is demodulated
from the playback signal. Specifically, the BD-ROM drive 111
reads data from the volume area 212 of the BD-ROM disc 100, and
transfers the data to the local storage 1610, control unit 1650,
or playback unit 1660.
The local storage 1610 is a rewritable storage device
embedded in the playback device 110. In the example shown in
Fig. 16, the local storage 1610 includes a card reader/writer

1611 and an HDD 1612. A memory card 1600 can be inserted into
the card reader/writer 1611. The card reader/writer 1611 can
write data onto and read data from the memory card 1600 inserted
therein. The HDD 1612 is embedded in the playback device 110.
Not limited to the structure, the HDD 1612 may be portable.
Furthermore, although not shown in Fig. 16, an external HDD may
be connected with the bus 1640 via a predetermined interface
to be used as the local storage 1610. The local storage 1610
stores additional contents or browser screens that are
downloaded by the BD-Live function from the server device 160
on the external network 150. Other than these, the local
storage 1610 may store parameters, tables and the like to be
used by the control unit 1650.
The operation unit 1620 detects various types of events,
and notifies the control unit 1650 of the contents of the
detected events . For example, the operation unit 1620 receives
a command, that has been transmitted wirelessly via infrared
rays or the like, from the remote control 14 0, decodes the
contents of the received command, and notifies the control unit
1650 of the decoded contents. The operation unit 1620 further
detects an operation of pressing a button such as a playback
start, pause, fast-forward, or winding provided on the front
panel of the playback device 110, identifies an instruction
corresponding to the pressed button, and notifies the control
unit 1650 of the identified instruction. The operation unit
1620 still further detects an operation of inserting or removing
the recording medium 100 into/from the BD-ROM drive 111, and
notifies the control unit 1650 of the detected operation.
The network interface 163 0 connects between the
external network 150 and the bus 1640 such that they can

communicate with each other. The control unit 1650 can
communicate with the server device 16 0 on the external network
150 via the network interface 1630. This communication
function is used for the BD-Live function.
The control unit 1650 is a micro computer system, and
includes a CPU 1651, a ROM 1652, and a RAM 1653. These elements
are connected with each other via an internal bus 1654. The
ROM 1652 stores programs for controlling the basic operations
of the playback device 110, namely stores firmware. The
firmware includes device drivers of the elements 111 and
1610-1660 connected with the bus 1640. The CPU 1651, for
example, reads the firmware from the ROM 1652 when the power
is turned on, and executes the firmware. This enables the
elements 111 and 1610-1660 to be initialized, and the Java
platform, namely, an environment for executing BD-J objects to
be prepared. The RAM 1653 provides the CPU 1651 with a work
area. The control unit 165 0 executes the firmware and
application programs by using the combination of the elements
1651-1653, and then controls the other elements in accordance
with the firmware and application programs.
The control unit 1650 especially reads a desired title
from the content recorded in the recording medium 100 or the
local storage 1610, and causes the external network 150 to play
back the title. More specifically, the control unit 1650 first
reads the playlist information corresponding to the title to
be played back, namely, reads the current playlist information
from the recording medium 100 or the control unit 1650. The
control unit 1650 then selects a playback-target AV clip, namely
a current AV clip, in accordance with the current playlist
information. Next, the control unit 1650 causes the BD-ROM

drive 111 or the local storage 1610 to supply the current AV
clip to the playback unit 1660.
Furthermore, the control unit 1650 in the BD-J mode,
in accordance with the application programs, generates graphic
elements for GUI, such as menus, as image data in JPEG or PNG
format, and then supplies the image data to the playback unit
1660. In the BD-J mode, the control unit 1650 also realizes
the BD-Live functions in accordance with the application
programs. That is to say, the control unit 1650 downloads image
data representing browser screens or the likes from the server
device 16 0 on the external network 15 0 via the network interface
1630, and supplies the image data to the playback unit 1660.
The playback unit 166 0, in accordance with an
instruction from the control unit 1650, reads the current AV
clip from the BD-ROM drive 111 or the local storage 1610. The
playback unit 1660 further divides an elementary stream with
a predetermined PID from the AV clip, and decodes the elementary
stream. The predetermined PID is preliminarily specified by
the control unit 1650. As a result of the decoding process,
a video plane is generated from the video stream, audio data
AD is generated from the audio stream, a PG plane is generated
from the PG stream, and an IG plane is generated from the IG
stream. Following this, the playback unit 1660 synthesizes
these planes into one video frame. Furthermore, in the BD-J
mode, the image data supplied from the control unit 1650 is also
synthesized into the video frame. The playback unit 1660
structures video data VD from the video frame after the
synthesizing process, and transmits the video data VD to the
HDMI transmission unit 1670, together with the audio data AD.
The HDMI transmission unit 1670 is connected with the

display device 120 by an HDMI cable 112 . The HDMI transmission
unit 1670 receives the video data VD from the playback unit 1660,
and converts the received video data into a video signal in the
HDMI format. Especially, in the case of the video signal, both
the left-view and the right-view video frames are multiplexed
into the video signal in time division. On the other hand, the
HDMI transmission unit 1670 receives the audio data AD from the
playback unit 1660, and converts the received audio data into
an audio signal in the HDMI format. The HDMI transmission unit
167 0 further multiplexes a synchronization signal and attached
data with the converted video and audio signals, and transmits
the result of the multiplexing to the display device 120 via
the HDMI cable 112. In so doing, the HDMI transmission unit
167 0 encrypts the transmission data by a protocol conforming
to the HDCP (High-bandwidth Digital Content Protection), and
performs a mutual authentication with the display device 120.
Note that the HDMI transmission unit 1670 may be embedded in
the playback unit 1660. Also, the audio signal may be,
separately from the video signal, transmitted to an external
amplifier or speaker connected with the display device 120 as
in a surround system.

Fig. 17 is a functional block diagram showing the
structure of the control unit 1650. As shown in Fig. 17, the
control unit 1650 includes a bus interface 1701, a user
operation detection module 1702, a virtual file system 1703,
and a playback control unit 1704. The control unit 1650
realizes the functional units 1701-1704 by executing firmware
embedded therein.
[0109] The bus interface 1701 connects each functional unit

in the control unit 1650 with the elements 111, 1610-1640, and
166 0 shown in Fig. 16 via the bus 164 0 so that they can
communicate with each other. Especially, the bus interface
1701, in accordance with an instruction from the virtual file
system 1703, reads scenario information of the playback target,
namely current scenario information DS and SS, from the BD-ROM
drive 111 and passes them to the playback control unit 1704.
Here, the scenario information includes dynamic scenario
information DS and static scenario information SS. The dynamic
scenario information DS includes a movie object file, BD-J
object file, and JAR file. The static scenario information SS
includes a playlist file and clip information file.
The user operation detection module 1702 receives a
notification INT from the operation unit 1620, and identifies
a user operation and a type of event from the notification INT.
The user operation detection module 1702 further transmits an
operation signal UO indicating the type of event to the playback
control unit 1704. Here, the types of events include an
insertion/removal of the recording medium 100 into/from the
BD-ROM drive 111, and pressing a button such as a playback start,
pause, fast-forward, or winding provided on the front panel of
the playback device 110.
The virtual file system 1703 manages the access by the
playback control unit 1704 to the files stored in the recording
medium 100 and the local storage 1610. Especially, the virtual
file system 1703 builds a virtual package from the contents
stored in the recording medium 100 and the additional contents
stored in the local storage 1610. The "virtual package" is a
directory/file structure virtually built in the RAM 1653 so as
to be equivalent to the directory/file structure 214 on the

BD-ROM disc 100 as shown in Fig. 2. The application program
accesses the recording medium 100 and the local storage 1610
via the virtual file system 1703. This makes it possible for
the contents recorded on them to be treated as contents that
are present in the same virtual package.
The virtual file system 1703 further reads an index file
IF from the virtual package in accordance with an instruction
COM from the playback control unit 1704, and passes the index
file IF to the playback control unit 1704. After that, the
virtual file system 1703 manages the access to the files stored
in the virtual package in accordance with the instruction COM
from the playback control unit 1704 and the operation signal
UO from the user operation detection module 17 02 . For example,
the virtual file system 1703 reads the current scenario
information DS and SS from the virtual package, and passes them
to the playback control unit 1704. Other than this, in
accordance with the instruction COM from the playback control
unit 1704, the virtual file system 1703 causes the BD-ROM drive
111 or the local storage 1610 to supply the current AV clip to
the playback unit 1660.
The playback control unit 1704 executes the firmware
to create an environment for executing an application program,
and further in the environment, reads the application program
from the dynamic scenario information DS and executes the
application program. And in accordance with the application
program, the playback control unit 1704 controls the elements
of the playback device 110.
With reference to Fig. 17, the playback control unit
17 04 includes a dynamic scenario memory 1741, a static scenario
memory 1742 , a mode management module 1743 , an HDMV module 1744 ,

a BD-J module 1745, and an AV playback library 1746.
The dynamic scenario memory 1741 and the static scenario
memory 1742 are both buffer memories embedded in the control
unit 1650. Different areas in the RAM 1653 are allocated to
the buffer memories 1741 and 1742, respectively. Not limited
to this, however, the buffer memories 1741 and 1742 may be
independent memory elements. The dynamic scenario memory 1741
stores the dynamic scenario information DS, and the static
scenario memory 1742 stores the static scenario information SS.
The mode management module 1743 receives the index file
IF from the virtual file system 1703, and stores the index file
IF. The mode management module 1743 further uses the index file
IF to control switching between operation modes of the playback
device 110 which follows switching between titles. More
specifically, the mode management module 1743 first selects an
item from the index table in the index file IF, in accordance
with the operation signal UO from the user operation detection
module 1702. When the selected item specifies a movie object,
the mode management module 1743 assigns the current dynamic
scenario information DS to the HDMV module 1744. Thus, the
operation mode of the playback device 110 transits to the HDMV
mode. On the other hand, when the selected item specifies a
BD-J object, the mode management module 174 3 assigns the current
dynamic scenario information DS to the BD-J module 1745. Thus,
the operation mode of the playback device 110 transits to the
BD-J mode. Furthermore, when the operation signal UO from the
user operation detection module 1702 indicates switching
between the operation modes, or when a request to switch between
operation modes is received from the HDMV module 1744 or the
BD-J module 1745, the mode management module 1743 switches the

module to which the current dynamic scenario information DS is
assigned, between the HDMV module 1744 and the BD-J module 1745 .
The mode management module 1743 includes a dispatcher
1743A. The dispatcher 1743A receives operation signals UO from
the user operation detection module 17 02, selects, from the
received operation signals UO, operation signals UO that suit
for the current operation mode, and passes the selected
operation signals UO to the HDMV module 1744 or the BD-J module
174 5 to which the current dynamic scenario information DS is
assigned. For example, when a received operation signal UO
indicates the fast-forward/rewind playback, the dispatcher
1743A passes the operation signal UO to the HDMV module 1744
in the HDMV mode, and to the BD-J module 1745 in the BD-J mode.
On the other hand, when a received operation signal UO indicates
the insertion of the recording medium 100 into the BD-ROM drive
111, the dispatcher 1743A transmits the instruction COM to the
virtual file system 17 03 via the AV playback library 174 6, which
instructs the virtual file system 1703 to read the index file
IF. When the index file IF is read in accordance with the
instruction, the index file IF is stored in the mode management
module 1743.
The HDMV module 1744 is a virtual DVD player, and
controls the process of playing back a title from the recording
medium 100 in the same manner as a general DVD player controls
the playback process. More specifically, the HDMV module 1744
reads a movie object from the dynamic scenario information DS
in the dynamic scenario memory 1741, and executes the navigation
commands contained in the movie object in the arrangement order
thereof. With this operation, the HDMV module 1744 specifies
processes indicated by the navigation commands, to the AV

playback library 1746 in order.
The BD-J module 1745 is a Java platform, and includes
an application manager 1745A and a virtual machine 1745B.
The BD-J module 1745, in response to an instruction from
the mode management module 1743, reads a BD-J object from the
dynamic scenario information DS in the dynamic scenario memory
1741. The application manager 1745A, in accordance with the
application management table 410 in the BD-J object, instructs
the virtual machine 1745B to start or terminate the application
programs.
The virtual machine 1745B is a Java virtual machine,
and has a work memory 1745C embedded therein. An area of the
RAM 1653 is allocated to the work memory 1745C. When the virtual
machine 1745B is instructed from the application manager 1745A
to start an application program, the virtual machine 174 5B reads
a JAR file that contains the application program from the
dynamic scenario information DS, and expands the JAR file in
the work memory 1745C. The virtual machine 1745B further reads
an xlet program to be activated from a class file that has been
expanded in the work memory 1745C, and then executes the xlet
program. Thus, methods contained in the xlet program are
converted into native codes for the CPU 1651, and the native
codes are passed to the AV playback library 1746. As a result,
instructions on processes in accordance with the application
program are provided to the AV playback library 174 6. On the
other hand, the virtual machine 1745B, when instructed by the
application manager 1745A to terminate an application program,
deletes an xlet program that is the body of the application
program from the work memory 174 5C after the termination process
of the application program or forcibly.

Processes in accordance with application programs
include BD-Live processes and graphics processes, as well as
the processes for playing back titles.
In the BD-Live processes, the virtual machine 1745B,
in accordance with an application program, causes the network
interface 163 0 to download additional contents from the server
device 160 to the local storage 1610, or download browser
screens to the playback unit 1660.
In the graphics processes, the virtual machine 1745B
generates image data GD in accordance with an application
program. The image data GD represents graphics images; graphic
elements for GUI such as menus, background images, animated
images, and the likes. In the process of generating the image
data GD, especially a JPEG file 821 or a PNG file 822 is used.
The JPEG file 821 and the PNG file 822 have been expanded in
the work memory 1745C from a JAR file in the dynamic scenario
information DS. The BD-J module 1745 further, in accordance
with an application program, transmits the image data GD to the
playback unit 1660 via the bus interface 1701 and the bus 1640.
Especially when 3D video images are played back from
the image data GD in the 2-plane mode, the virtual machine 1745B
first generates and passes both the left-view and right-view
image data GD to the playback unit 1660. The virtual machine
1745B then transmits rendering instructions to the playback
unit 1660 with appropriate timing. Thus, the virtual machine
1745B controls the playback unit 1660 to synthesize the
left-view and the right-view image data GD with the left-view
and the right-view video frames, respectively. On the other
hand, when 3D video images are played back from the image data
GD in the offset mode, the virtual machine 1745B transmits the

image data GD representing usual 2D video images and the offset
value thereof to the playback unit 1660 . The playback unit 1660
generates the left-view and the right-view image data from the
image data GD based on the offset value, and then synthesizes
the left-view and the right-view image data with the left-view
and the right-view video frames, respectively.
Each time the virtual machine 1745B reads a BD-J object
from the dynamic scenario information DS, the virtual machine
1745B compares the image playback state value 620 presented by
the BD-J obj ect with a current image playback state value. Note
that the current image playback state value is held in the AV
playback library 1746. When the compared two image playback
state values are different, the BD-J module 1745 changes the
state of the playback device 110 according to the image playback
state value 620 presented by the BD-J object. More specifically,
the BD-J module 1745 changes the state as follows.
When the image playback state value 620 indicates State
1, the BD-J module 174 5 prohibits application programs from
performing the processes for playing back 3D video images.
Especially, both the offset mode and the 2-plane mode are
disabled. On the other hand, the BD-J module 1745 permits
application programs to perform the BD-Live processes.
When the image playback state value 62 0 indicates State
2, the BD-J module 1745 prohibits application programs from
using the 2-plane mode, but permits application programs to
perform the processes for playing back 3D video images from
video streams, use the offset mode, and perform the BD-Live
processes.
When the image playback state value 62 0 indicates State
3, the BD-J module 1745 permits application programs to perform

the processes for playing back 3D video images from video
streams, use the 2-plane mode and the offset mode, and perform
the BD-Live processes, but restricts the cache area that can
be used in the BD-Live processes.
When the image playback state value 62 0 indicates State
4, the BD-J module 1745 permits application programs to perform
the processes for playing back 3D video images from video
streams, use the 2-plane mode and the offset mode, but prohibits
application programs from performing the BD-Live processes,
that is to say, the connections with the external network 150.
When the compared two image playback state values
indicate other than the combination of States 1 and 2, the BD-J
module 1745 uses the application manager 1745A to cause the
virtual machine 1745B to forcibly terminate all application
programs. More specifically, as indicated by the dotted arrows
shown in Fig. 7, when the playback device 110 switches between
States 1 and 2, the BD-J module 1745 need not cause the virtual
machine 1745B to terminate application programs. On the other
hand, as indicated by the solid arrows shown in Fig. 7, when
the playback device 110 switches between States 1 and 3, States
1 and 4, States 2 and 3, States 2 and 4, or States 3 and 4, the
BD-J module 1745 causes the virtual machine 1745B to forcibly
terminate application programs. In that case, all the
application programs are terminated, regardless of whether they
are title-bound, disc-bound, or disc-unbound. Therefore, all
the xlet programs and all the parameters used by the xlet
programs are deleted from the work memory 1745C.
Furthermore, when the compared two image playback state
values indicate other than the combination of States 3 and 4,
that is to say, when the two values indicate the combination

of States 1 and 3, States 1 and 4, States 2 and 3, or States
2 and 4, the BD-J module 1745 causes the playback unit 1660 to
change the memory area for storing image data. On the other
hand, when the compared two image playback state values indicate
the combination of States 3 and 4, the BD-J module 174 5 causes
the playback unit 1660 to allocate or free the cache area for
the BD-Live processes. In the cache area, image data such as
browser screens downloaded from the server device 160 on the
external network 150 are stored.
The BD-J module 1745 specifies either the offset mode
or the 2-plane mode to the playback unit 166 0 with regard to
the image data playback processes in accordance with the image
playback state value 62 0 presented by the BD-J object. More
specifically, when the image playback state value 620 indicates
State 2, the BD-J module 1745 specifies the offset mode to the
playback unit 1660. On the other hand, when the image playback
state value 620 indicates State 3 or 4, the BD-J module 1745
specifies the offset mode or the 2-plane mode that is selected
by the application program, to the playback unit 1660.
When the BD-J module 1745 changes the state in
accordance with the image playback state value 62 0 presented
by the BD-J object as described above, the BD-J module 1745
causes the AV playback library 1746 to update the original image
playback state value to the image playback state value 620.
The AV playback library 1746 instructs an AV playback
process or a playlist playback process in accordance with an
instruction from the HDMV module 1744 or the BD-J module 1745.
The "AV playback process" is a basic process of optical disc
playback devices, and includes playback processes performed by
general DVD players and CD players. More specifically, the AV

playback process includes a start/stop of the playback process,
pause and its release, release of still picture function,
fast-forward and rewind, switch of audio, switch of subtitle,
and switch of angle. On the other hand, the "playlist playback
process" is basically a title playback process in accordance
with the static scenario information SS. That is to say, in
the playlist playback process, the AV playback library 1746
selects a current AV clip in accordance with the current
playlist information, and causes the virtual file system 1703
to supply the current AV clip to the playback unit 1660. Other
than this, the playlist playback process includes the process
for building the virtual package, and the process for
transferring the scenario information DS and SS from the virtual
package to each of the dynamic scenario memory 1741 and the
static scenario memory 1742. The functions necessary for the
AV playback process and the playlist playback process are
implemented in the AV playback library 1746 as the Application
Program Interface (API). The AV playback library 174 6 sends
instructions to the BD-ROM drive 111, the local storage 1610,
the playback unit 1660 and the like via the virtual file system
17 03 by executing the API in correspondence with specified
processes. Thus, the AV playback library 174 6 causes each
element to execute the specified processes.
When the current playlist information belongs to the
3D playlist file, the AV playback library 1746 reads the 3D
metadata 1103 from the clip information file in the static
scenario information SS, and sends the 3D metadata 1103 to the
playback unit 1660.
The AV playback library 1746 includes a register 1746A.
The register 1746A stores parameters indicating the current

states of the playback device 110 and the display device 120,
parameters indicating states that can be set in each device,
and parameters indicating initial states of each device. The
parameters indicating the current states include stream
selection numbers of the audio stream and the PG stream that
are targeted to be decoded, identifiers of the current playlist
information and the current playitem information, and the
current image playback state value. The parameters indicating
states that can be set in each device include types of selectable
audio/subtitle languages, and types of audio data encoding
methods.
The AV playback library 1746 refers to the register
1746A in accordance with an instruction from the HDMV module
1744 or the BD-J module 1745. Thus, elementary streams that
can be played back by both the playback device 110 and the display
device 12 0 are detected from the elementary streams registered
in the stream selection tables of each piece of play item
information. The AV playback library 174 6 further selects an
elementary stream having the smallest stream selection number
among the detected elementary streams, and stores the stream
selection number into the register 1746A. Also, attributes
such as the encoding format and language type, among the
attributes of the elementary stream having the smallest stream
selection number, are read from the stream attribute
information in the clip information file, and stored into the
register 1746A. The AV playback library 1746 further specifies
PID for the selected elementary stream to the playback unit 1660 .
In so doing, the AV playback library 174 6 transfers the
information such as the encoding format, which is necessary for
decoding the selected elementary stream, from the register

1746A to the playback unit 166 0.

Fig. 18 is a functional block diagram showing the
structure of the playback unit 1660. As shown in Fig. 18, the
control unit 1650 includes a bus interface 1801, a pair of track
buffers 18 02A and 18 02B, a pair of demultiplexers 18 03A and
1803B, a primary video decoder 1804A, a secondary video decoder
1804B, a PG decoder 1804C, an IG decoder 1804D, a primary audio
decoder 1804E, a secondary audio decoder 1804F, a rendering
engine 1805, an image decoder 1804G, a primary video plane
memory 1806A, a secondary video plane memory 1806B, an image
memory 1810, an addition unit 18 07, and a mixer 1808 . The image
memory 1810 includes a PG plane memory 1806C, an IG plane memory
1806D, a background (BG) plane memory 1806E, and an image data
area 1811. These functional units are implemented in one single
chip. Not limited to this, however, some functional units may
be implemented in other chips.
The bus interface 18 01 connects each functional unit
in the playback unit 166 0 with the BD-ROM drive 111, the local
storage 1610, and the control unit 1650 via the bus 1640 so that
they can communicate with each other. Especially, the bus
interface 1801, in accordance with an instruction from the
virtual file system 1703, transfers current AV clips MCL and
SCL from the BD-ROM drive 111 or the local storage 1610 to the
track buffers 1802A and 1802B. Here, the AV clip MCL is an AV
clip specified in the main path information (hereinafter, such
AV clip is referred to as main-path AV clip) , and is transferred
to the first track buffer 18 02A; and the AV clip SCL is an AV
clip specified in the sub-path information (hereinafter, such
AV clip is referred to as sub-path AV clip) , and is transferred

to the second track buffer 1802B.
The track buffers 1802A and 1802B are both a
First-In-First-Out (FIFO) memory embedded in the playback unit
1660. The track buffers 1802A and 1802B temporarily store the
AV clips MCL and SCL read from the bus interface 1801.
The first demultiplexer 18 03A receives, from the AV
playback library 174 6, the PID for the elementary stream to be
decoded from the main-path AV clip MCL. On the other hand, the
first demultiplexer 18 03A reads the main-path AV clip MCL in
units of source packets from the first track buffer 1802A, and
extracts the TS packet from each source packet. The first
demultiplexer 1803A further reads the PID from the TS header
of each TS packet, and compares the read PID with the PID for
the elementary stream targeted to be decoded. When the both
PIDs match, the first demultiplexer 1803A collects the TS packet
containing the matched PID. PES packets are restored from the
TS packets that are collected in this way, and each restored
PES packet is sent to any of the six types of decoders 18 04A
through 1804F in accordance with the PID for the elementary
stream targeted to be decoded. For example, when the PID of
a TS packet is 0x1011, the PES packet restored from the TS packet
is sent to the primary video decoder 1804A. When the PID of
a TS packet is in the range from OxlBOO to OxlBlF, the PES packet
restored from the TS packet is sent to the secondary video
decoder 1804B. When the PID of a TS packet is in the range from
0x1100 to OxlllF, the PES packet restored from the TS packet
is sent to the primary audio decoder 18 04E. When the PID of
a TS packet is in the range from 0x1A00 to 0x1AlF, the PES packet
restored from the TS packet is sent to the secondary audio
decoder 18 04F. When the PID of a TS packet is in the range from

0x1200 to 0xl21F, the PES packet restored from the TS packet
is sent to the PG decoder 18 04C. When the PID of a TS packet
is in the range from 0x1400 to 0x141F, the PES packet restored
from the TS packet is sent to the IG decoder 18 04D.
Similarly, the second demultiplexer 1803B receives,
from the AV playback library 1746, the PID for the elementary
stream to be decoded from the sub-path AV clip SCL. On the other
hand, the second demultiplexer 1803B reads the sub - path AV clip
SCL in units of source packets from the second track buffer 1802B,
and extracts the TS packet from each source packet. The second
demultiplexer 1803B further restores PES packets from TS
packets having PIDs that match the PIDs for the elementary
streams targeted to be decoded, and sends each of the restored
PES packets to any of the six types of decoders 18 04A through
18 04F in accordance with the PID. Especially, when the PID of
a TS packet is 0x1012, the PES packet restored from the TS packet
is sent to the primary video decoder 1804A.
It should be noted here that generally, each of the AV
clips MCL and SCL includes information that is to be used as
the dynamic scenario information by the application program.
Such dynamic scenario information includes information
concerning graphic elements for GUI such as the navigation
button included in the IG stream. When the first demultiplexer
18 03A or the second demultiplexer 18 03B divides such
information from each of the AV clips MCL and SCL, the
demultiplexer transfers the information to the dynamic scenario
memory 1741 in the control unit 1650 via the bus interface 1801.
The primary video decoder 18 04A receives PES packets
of the left-view video stream from the first demultiplexer 1803A,
and PES packets of the right-view video stream from the second

demultiplexer 18 03B. The received PES packets are stored in
the buffer memory in the primary video decoder 1804A. In
parallel with this, the primary video decoder 18 04A reads the
PES packets from the buffer memory, removes the PES headers from
the PES packets, extracts pictures from the remaining PES
payloads, and decodes the pictures. The primary video decoder
1804A further writes non-compressed pictures into the primary
video plane memory 1806A at the times indicated by the PTSs
described in the PES headers. In the 3D video image playback
process, the primary video decoder 1804A alternately decodes
the left-view and right-view pictures, and writes the decoded
pictures into the primary video plane memory 18 06A.
The secondary video decoder 1804B has the same structure
as the primary video decoder 18 04A. Using the structure, the
secondary video decoder 1804B receives PES packets of the
secondary video stream from the first demultiplexer 1803A and
the second demultiplexer 18 03B, extracts pictures from the PES
packets, and decodes the pictures . The secondary video decoder
1804B further writes non-compressed pictures into the secondary
video plane memory 18 06B at the times indicated by the PTSs
described in the PES packets.
The PG decoder 1804C receives PES packets of the PG
stream from the first demultiplexer 1803A and the second
demultiplexer 1803B, extracts image data from the PES packets,
and decodes the image data. The PG decoder 18 04C further writes
non-compressed image data, namely PG planes, into the PG plane
memory 18 06C at the times indicated by the PTSs described in
the PES packets.
The IG decoder 1804D receives PES packets of the IG
stream from the first demultiplexer 1803A and the second

demultiplexer 1803B, extracts image data from the PES packets,
and decodes the image data. The IG decoder 18 04D further writes
non-compressed image data, namely IG planes, into the IG plane
memory 1806D at the times indicated by the PTSs described in
the PES packets. The IG decoder 18 04D is used in the HDMV mode.
The IG decoder 18 04D is not used in the BD-J mode.
The primary audio decoder 1804E receives PES packets
of the primary audio stream from the first demultiplexer 18 03A
and the second demultiplexer 18 03B, and stores the PES packets
into an internal buffer memory. In parallel with this, the
primary audio decoder 18 04E reads the PES packets from the
buffer memory, and removes the PES headers from the PES packets.
The primary audio decoder 1804E further extracts audio data in
the LPCM format from the remaining PES payloads, and decodes
the audio data. Following this, the primary audio decoder 1804E
sends non-compressed audio data to the mixer 1808 at the times
indicated by the PTSs described in the PES headers.
The secondary audio decoder 18 04F has the same structure
as the primary audio decoder 1804E. Using the structure, the
secondary audio decoder 1804F receives PES packets of the
secondary audio stream from the first demultiplexer 18 03A and
the second demultiplexer 18 03B, extracts audio data in the LPCM
format from the PES packets, and decodes the audio data.
Following this, the secondary audio decoder 18 04F sends
non-compressed audio data to the mixer 1808 at the times
indicated by the PTSs described in the PES headers.
The image decoder 18 04G receives the image data GD from
the BD-J module 1745 in the control unit 1650, and decodes the
image data GD. The image decoder 18 04G further writes
non-compressed image data into the image data area 1811.

Furthermore, in the BD-Live processes, the image decoder 18 04G
uses a portion of the image data area 1811 as a cache area. The
image decoder 18 04G decodes image data such as browser screens
downloaded from the server device 160, and stores the decoded
image data into the cache area. In particular, both the current
and previous image data are stored in the cache area.
Each of the video plane memories 18 06A and 18 06B is an
area allocated in a memory element embedded in the playback unit
1660, and includes a two-dimensional array. The size of the
array is equivalent to the resolution of a video frame. Each
element of the array stores a piece of pixel data. Each piece
of pixel data is composed of color coordinates and an a (alpha)
value (opacity) . The color coordinates are represented by RGB
values or YCrCb values. Accordingly, the array can store one
video plane. In the 3D video image playback processes, two of
the two-dimensional arrays of the same size are allocated in
the primary video plane memory 1806A. The left-view and
right-view video planes are separately written into the two
two-dimensional arrays.
The image memory 1810 is an area allocated in a memory
element embedded in the playback unit 1660. Portions of the
image memory 1810 are separately allocated to the PG plane
memory 1806C, the IG plane memory 1806D, and the BG plane memory
1806E, and the remaining area is allocated to the image data
area 1811. Each of the plane memories 1806C, 1806D, and 1806E
includes two two-dimensional arrays of the same size. Each
element of the array stores a piece of pixel data. Each piece
of pixel data is composed of color coordinates and an a value.
The color coordinates are represented by RGB values or YCrCb
values. In each of the plane memories 1806C, 1806D, and 1806E,

while the current plane is held in one of the two arrays, the
next plane is written into the other. This can realize
so-called double-buffering, and thus prevent flicker of video
images played back from the planes. Note that, in general,
different plane memories have different array sizes. The
capacity of the area to be allocated to the IG plane memory 18 06D
is specif ied by the BD-J module 1745, and in particular, changed
depending on the image playback state value 62 0 presented by
the BD-J object. More specifically, in States 3 and 4 shown
in Fig. 7, the capacity of the IG plane memory 1806D is set to
double the value in States 1 and 2.
The rendering engine 18 05 is provided with APIs for
graphics processing such as Java 2D or OPEN-GL. The rendering
engine 18 05 is especially used for graphics processing by the
BD-J module 1745 . More specif ically, the BD-J module 1745 first
transfers the image data GD to the image data area 1811. The
BD-J module 1745 next sends an instruction to the rendering
engine 18 05 in accordance with the application program. In
accordance with the instruction, the rendering engine 18 05
performs graphics processing such as α-blending (Porter-Duff
operation) onto the image data GD in the image data area 1811.
Thus, the rendering engine 1805 generates an image plane
representing graphics images and a BG plane representing
background images from the image data GD. The rendering engine
18 05 further writes the image plane into the IG plane memory
1806D, and writes the BG plane into the BG plane memory 18 06E.
Furthermore, when instructed by the BD-J module 1745 to perform
the process for playing back 3D video images in the 2 -plane mode,
the rendering engine 1805 generates both the left-view and
right-view image planes from the image data GD, and writes the

image planes into the IG plane memory 1806D.
In the 2D video image playback process, the addition
unit 1807 synthesizes the planes written in the plane memories
1806A through 1806E into one video frame as they are. In the
3D video image playback process, the addition unit 1807 first
performs the cropping process onto any of the PG, IG, image,
and BG planes, and generates pairs of left-view and right-view
planes from the planes having been subjected to the cropping
process. In so doing, the addition unit 1807 determines the
planes to which the cropping process should be performed, in
accordance with an instruction from the BD-J module 1745. In
the cropping process of the PG and IG planes, the offset value
indicated by the 3D metadata 1103 is used. In the cropping
process of the image and BG planes, the offset value passed from
the BD-J module 1745 is used. Next, the addition unit 1807
synthesizes the left-view video plane, left-view PG plane,
left-view IG plane (or image plane) , and left-view BG plane into
one left-view video frame. Similarly, the addition unit 1807
synthesizes the right-view planes into one right-view video
frame. In so doing, in the 2-plene mode, the addition unit 1807
adjusts the timing at which the image plane is synthesized into
the video frame, to the timing indicated by the rendering
instruction from the BD-J module 1745. Thus, the left-view
planes are correctly synthesized into one left-view video
frame; and the right-view planes are correctly synthesized into
one right-view video frame. The addition unit 1807 converts
the video frames having been synthesized correctly in this way,
into video data VD, and transmits the video data VD to the HDMI
transmission unit 1670.
The mixer 1808 generates audio data AD representing a

mixed sound by mixing the non-compressed audio data received
respectively from the primary audio decoder 1804E and the
secondary audio decoder 1804F. The mixer 18 08 further
transmits the audio data AD to the HDMI transmission unit 1670.

[0159] Fig. 19 is a schematic diagram showing an example of
the IG plane memory area, the PG plane memory area, the BG plane
memory area, and the image data area that are allocated in the
image memory 1810. In the example shown in Fig. 19, the total
capacity of the image memory 1810 is 81.5 MB.
When the image playback state value 62 0 presented by
the BD-J object indicates State 1 or 2, the BD-J module 174 5
assigns 16 MB to the IG plane memory area 1901, 2 MB to each
of the PG plane memory area 1902 and the BG plane memory area
1903, and the remaining 61.5 MB to the image data area 1904.
The BD-J module 1745 further allocates a 16-MB area in the image
data area 1904 to the cache area 1905 for the BD-Live.
Especially, since the IG plane memory area 1901 has the capacity
of 16 MB, the IG plane memory area 1901 can store up to two image
planes each having the resolution of 1920 x 1080 (= 8 MB) .
Accordingly, in State 2, the offset mode can add depth
perception to graphics images represented by an image plane
having the resolution of 1920 x 1080.
When the image playback state value 620 presented by
the BD-J object indicates State 3 or 4, the BD-J module 174 5
assigns 3 2 MB to the IG plane memory area 1911, 2 MB to each
of the PG plane memory area 1912 and the BG plane memory area
1913, and the remaining 45.5 MB to the image data area 1914.
Especially, since the IG plane memory area 1911 has the capacity

of 32 MB, the IG plane memory area 1911 can store up to four
image planes each having the resolution of 1920 x 1080 (= 8 MB) .
Accordingly, in States 3 and 4, the 2-plane mode can add depth
and three-dimensional shape perception to graphics images
represented by an image plane having the resolution of 1920 x
1080 . Especially, the 2-plane mode can produce more expressive
stereoscopic effects than the offset mode. Therefore, in
States 3 and 4, for example, irregularities and curves of the
surface of a menu can be expressed more real than in State 2 .
When the BD-J module 1745 is to switch the playback
device 110, for example, from State 2 to State 4, the BD-J module
1745 first frees the cache area 1905 from the image data area
1904. Next, the BD-J module 1745 allocates the free area made
available by the freeing, to the IG plane memory area 1911. This
increases the capacity of the IG plane memory area from 16 MB
to 32 MB, and accordingly enables the 2-plane mode . On the other
hand, the cache area 1905 disappears . This disables the BD-Live
function with network connections. Conversely, when the
playback device 110 is to be switched from State 4 to State 2,
first, a 16-MB area is freed from the 32-MB IG plane memory area
1911. Next, the free area made available by the freeing is
allocated to the image data area 1904 as the cache area 1905.
This enables the BD-Live function with network connections . On
the other hand, the capacity of the IG plane memory area
decreases from 32 MB to 16 MB. This disables the 2-plane mode.
The above-described freeing and allocating of a 16-MB
cache area and exchanging of a 16-MB area between the image data
area and the IG plane memory area are performed similarly in
switching between States 1 and 4, switching between States 1
and 3, and switching between States 3 and 4. This enables the

2-plane mode and the BD-Live function selectively.
When the image playback state value 620 presented by
the BD-J object indicates State 3, the BD-J module 1745
allocates an area in the 45.5-MB image data area 1914 as the
cache area for BD-Live, which is not shown in Fig. 19. Note
that the cache area has a limited capacity smaller than 16 MB,
the capacity of the cache area 1905 in States 1 and 2.
Furthermore, the remainder of the image data area 1914 has a
capacity less than 45 . 5 MB because of the allocation of the cache
area. Accordingly, switching between State 3 and another,
changes both the capacities of the image data area and the cache
area. For this reason, a type of application programs cannot
run in State 3; the type of application programs belongs to the
application programs that are used in State 1, 2, or 4, and runs
under the condition that the capacities of the image data area
and the cache area be 45 . 5 MB and 16 MB, respectively. However,
another type of application programs that can run under the
condition that the capacities of the image data area and cache
area are smaller than 45.5 MB and 16 MB, respectively, can
realize the BD-Live functions and execute the 2-plane mode with
use of the 32-MB IG plane memory area 1911. The type of
application programs can, for example, display both a GUI screen
built thereby and a browser screen downloaded from an external
network simultaneously on the display device 120, and can add
further improved depth and three-dimensional shape perception
to the screens.
As described above, the playback device 110 causes
application programs to dynamically switch among the four types
of states, namely, States 1-4. Thus, the playback device 110
allows the application programs to selectively use the 2-plane

mode and the BD-Live functions while maintaining the total
capacity of the image memory at a constant level. The playback
device 110 further allows application programs to
simultaneously use the 2-plane mode and the BD-Live functions
when the application programs can run under the condition that
the image data area and cache area have the reduced capacities.

Fig. 20 is a schematic diagram showing the image planes
stored in the IG plane memory area 1911 in the offset mode and
2-plane mode. The rendering engine 1805 in the offset mode,
like the one in the playback process of 2D video images, writes
an image plane 2001 of 1920 x 1080 (= 8 MB) into the IG plane
memory area 1911. Accordingly, the rendering engine 1805
requires only one handle for the image plane 2001. On the other
hand, the rendering engine 1805 in the 2-plane mode writes two
image planes of 1920 x 1080 into the IG plane memory area 1911.
One of them is a left-view image plane 2003 and the other is
a right-view image plane 2004. In this case, the rendering
engine 1805 logically connects the two image planes 2003 and
2004 in a horizontal direction to constitute an image plane 2002
having double the number of the horizontal pixels, namely, the
image plane of 3 84 0 x 1080, and then provides one handle to the
image plane 2002. Thus, the rendering engine 1805 allows
application programs to operate the left-view image plane 2003
and the right-view image plane 2004 as left- and right-halves
of the single image plane 2002, respectively. For example, when
an instruction from the BD-J module 1745 specifies a rendering
operation in the left half of the image plane 2002, the rendering
engine 1805 writes the left-view image plane 2003 into the IG
plane memory area 1911. On the other hand, when an instruction

from the BD-J module 1745 specifies a rendering operation in
the right half of the image plane 2002, the rendering engine
1805 writes the right-view image plane 2004 into the IG plane
memory area 1911. Furthermore, when an instruction from the
BD-J module 174 5 specifies a rendering operation in the entirety
of the image plane 2002, the rendering engine 1805 writes both
the left-view image plane 2003 and the right-view image plane
2004 into the IG plane memory area 1911. Thus, the rendering
engine 1805 allows application programs to operate the image
planes with one handle in both the offset mode and the 2-plane
mode.

Fig. 21 is a functional block diagram showing the
addition unit 1807 in the state 1, namely, in the playback
process of 2D video image. In the state 1, the addition unit
1807 includes four adders 2101-2104. The first adder 2101
synthesizes a primary video plane 2110 with a secondary video
plane 2111 and sends the synthesized video plane to the second
adder 2102. The second adder 2102 synthesizes the video plane
received from the first adder 2101 with a BG plane 2112 and sends
the synthesized video plane to the third adder 2103 . The third
adder 2103 synthesizes the video plane received from the second
adder 2102 with a PG plane 2113 and sends the synthesized video
plane to the fourth adder 2104. The fourth adder 2104
synthesizes the video plane received from the third adder 2103
with an image plane (or IG plane) 2114. The fourth adder 2104
further converts the synthesized video plane as one video frame
into video data VD, and sends the video data VD to the HDMI
transmission unit 1670.
Fig. 22 is a functional block diagram showing the

addition unit 18 07 in the state 2. In the state 2, the addition
unit 1807 includes a switch 2200, three adders 2201-2203, and
three cropping processors 2211-2213. The following
explanation assumes the BD-J mode for convenience's sake, but
the explanation is applicable to the HDMV mode as well.
The switch 2200 sends a left-view video plane 2220 and
a right-view video plane 2221 to the first adder 2201 in the
order of the PTS. When the PTSs of the left-view video plane
2220 and the right-view video plane 2221 are the same, the switch
2200 sends the 2220 first before the 2221. It should be noted
here that although not shown in Fig. 22, when there are two types
of secondary video planes, namely left-view and right-view, a
similar switch is used so that the two types of secondary video
planes are alternately read into the addition unit 1807 to be
synthesized with a video plane output from the switch 2200.
The first adder 2201 receives alternately the left-view
video plane 2220 and the right-view video plane 2221 from the
switch 2200. On the other hand, the first adder 2201 receives
alternately a left-view BG plane and a right-view BG plane from
the first cropping processor 2211. The first adder 2201
synthesizes the left-view video plane 2220 with the left-view
BG plane, and synthesizes the right-view video plane 2221 with
the right-view BG plane. The two types of video planes after
the synthesizing are sent to the second adder 22 02 alternately.
The second adder 22 02 receives alternately the
left-view video plane and the right-view video plane from the
first adder 2201. On the other hand, the second adder 2202
receives alternately a left-view PG plane and a right-view PG
plane from the second cropping processor 2212 . The second adder
2202 synthesizes the left-view video plane with the left-view

PG plane, and synthesizes the right-view video plane with the
right-view PG plane. The two types of video planes after the
synthesizing are sent to the third adder 22 03 alternately.
The third adder 2203 receives alternately the left-view
video plane and the right-view video plane from the second adder
2202. On the other hand, the third adder 2203 receives
alternately a left-view image plane and a right-view image plane
from the third cropping processor 2213. The third adder 2203
synthesizes the left-view video plane with the left-view image
plane, and synthesizes the right-view video plane with the
right-view image plane. The third adder 2203 further converts
the synthesized video plane as one video frame into video data
VD, and sends the video data VD to the HDMI transmission unit
1670.
The first cropping processor 2211 performs a cropping
process onto the BG plane 2222 by using an offset value passed
from the BD-J module 1745 . Thus, the BG plane 2222 is converted
into the left-view BG plane and the right-view BG plane
alternately.
The second cropping processor 2212 performs a cropping
process onto the PG plane 2223 by using an offset value indicated
by the 3D metadata 1103. Thus, the PG plane 2223 is converted
into the left-view PG plane and the right-view PG plane
alternately.
The third cropping processor 2213 performs a cropping
process onto the image plane 2224 by using an offset value passed
from the BD-J module 1745. Thus, the image plane 2224 is
converted into the left-view image plane and the right-view
image plane alternately.
Fig. 23 is a schematic diagram showing the cropping

process performed onto the PG plane GP by the second cropping
processor 2212. With reference to Fig. 23, the PG plane GP
includes a graphic element ST representing a subtitle "I love
you". With regard to the portions other than the graphic
element ST, the a value is set to "0", meaning "transparent".
The second cropping processor 2212 first searches the
3D metadata 1103 shown in Fig. 12, for a table 1201 that is
assigned to PID=0xl200 of the PG stream. The second cropping
processor 2212 then searches the table 1201 for an offset entry
1204 that is valid at the current point in time, and obtains
an offset value 1203 of the offset entry 1204.
Next, the second cropping processor 2212 accesses the
primary audio decoder 1804E and judges which of the left view
and the right view is synthesized with the PG plane GP. The
second cropping processor 2212 then shifts the graphic element
ST in the horizontal direction by the number of pixels PX in
the PG plane GP. The number of pixels PX is equivalent to the
offset value 1203. On the other hand, the direction of the
shifting depends on the judgment result.
When the left view is synthesized with the PG plane GP:
when the offset value 1203 is positive, the graphic element ST
shifts to the right; and when the offset value 12 03 is negative,
the graphic element ST shifts to the left. More specifically,
when the offset value 12 03 is positive, a transparent belt B1L
having a width that is equivalent to the number of pixels PX
is added to the left side of the original PG plane GP, and a
transparent belt B1R having the same width is removed from the
right side of the original PG plane GP. Thus, the original PG
plane GP is replaced with a left-view PG plane LGP. A distance
DL between the left edge of the left-view PG plane LGP and the

graphic element ST is longer than a distance DO between the left
edge of the original PG plane GP and the graphic element ST,
by the number of pixels PX. That is to say, the graphic element
ST shifts to the right from the original position. The reverse
takes place when the offset value 1203 is negative.
When the right view is synthesized with the PG plane
GP: when the offset value 1203 is positive, the graphic element
ST shifts to the left; and when the offset value 1203 is negative,
the graphic element ST shifts to the right. More specifically,
when the offset value 1203 is positive, a transparent belt B2L
having a width that is equivalent to the number of pixels PX
is removed from the left side of the original PG plane GP, and
a transparent belt B2R having the same width is added to the
right side of the original PG plane GP. Thus, the original PG
plane GP is replaced with a right-view PG plane RGP. A distance
DR between the left edge of the left-view PG plane RGP and the
graphic element ST is shorter than the distance DO between the
left edge of the original PG plane GP and the graphic element
ST, by the number of pixels PX. That is to say, the graphic
element ST shifts to the left from the original position. The
reverse takes place when the offset value 1203 is negative.
In this way, the second cropping processor 2212
generates the left-view PG plane LGP and the right-view PG plane
RGP from one PG plane GP, and sends them alternately to the second
adder 22 02. The horizontal distance between the graphic
elements ST in them is double the number of pixels PX, namely
double the offset value 1203. The viewer recognizes the
positional difference as a binocular parallax, and the viewer
sees the subtitle "I love you" at a depth relative to the screen.
The first cropping processor 2 211 performs a similar cropping

process onto the BG plane 2222, and the third cropping processor
2213 performs a similar cropping process onto the image plane
2224.
Fig. 24 is a functional block diagram showing the
addition unit 1807 in the states 3 and 4. In the states 3 and
4, the addition unit 1807 includes two mode switches 2411 and
2412 in addition to the functional units shown in Fig. 22.
In accordance with an instruction from the BD-J module
1745, the first mode switch 2411 switches between the
destinations of a left-view image plane 2420 as the mode
switches between the offset mode and the 2-plane mode. In the
offset mode, the first mode switch 2411 sends the left-view
image plane 2420 to the third cropping processor 2213. Thus,
a pair of left-view and right-view image planes is generated
from the left-view image plane 2420. In the 2-plane mode, the
first mode switch 2411 sends the left-view image plane 2420 to
the second mode switch 2412.
The second mode switch 2412, in conjunction with the
switch 2200, sends the left-view image plane 2420 and a
right-view image plane 2421 alternately to the third adder 2203 .
Especially, when the switch 2200 sends the 2220, the second mode
switch 2412 sends the left-view image plane 2420; and when the
switch 2200 sends the 2221, the second mode switch 2412 sends
the right-view image plane 2421. With this structure, the third
adder 22 03 can synthesize the video plane and the image plane
correctly.

Fig. 25 is a flowchart showing the process for switching
between states of the playback device 110 by the BD-J module

1745. The following explanation assumes, for convenience's
sake, that the process for switching between titles is performed
when a BD-ROM disc is newly inserted into the BD-ROM drive 111.
The following explanation is also applicable to the process for
switching between titles that is performed in response to a user
operation or a request for an application program while the
recording medium 100 is inserted in the BD-ROM drive 111.
Step S2501: the operation unit 1620 detects insertion
of the recording medium 100 into the BD-ROM drive 111, and sends
a notification INT indicating the insertion, to the user
operation detection module 1702. In accordance with the
notification INT, the user operation detection module 1702
transmits an operation signal UO to the mode management module
1743 . In the mode management module 1743 , the dispatcher 1743A,
via the AV playback library 174 6, requests the virtual file
system 1703 to read the index file IF. Next, the mode management
module 1743 refers to the item "first play" 301 in the index
table in the index file IF, and then identifies an object
specified in the item. Here, the object is assumed to be the
BD-J object. In this case, the mode management module 1743
sends an instruction to the virtual file system 1703 via the
AV playback library 174 6, thereby causing the virtual file
system 1703 to transfer the BD-J object to the dynamic scenario
memory 1741. On the other hand, the mode management module 1743
assigns the current dynamic scenario information DS to the BD-J
module 1745. In response to that, the BD-J module 1745 reads
the BD-J object from the dynamic scenario information DS in the
dynamic scenario memory 1741.
Step S2502 : the BD-J module 1745 reads the current image
playback state value from the AV playback library 1746, and then

compares it with the image playback state value 620 presented
by the BD-J object. When the two image playback state values
match, or when the combination thereof indicates switching
between States 1 and 2 , the process proceeds to Step S2503 . When
the combination of the two image playback state values indicates
anything other than the switching between States 1 and 2, the
process proceeds to Step S2504.
Step S2503: the state of the playback device 110
requested by the BD-J object and the state thereof before the
insertion of the recording medium 100 are equivalent to each
other or the combination of States 1 and 2. Accordingly, the
BD-J module 174 5 does not change the areas in the image memory
1810. On the other hand, when the BD-J object requests the
switching between States 1 and 2, the BD-J module 1745, in
accordance with the request, specifies either the 2D video image
playback process or the 3D video image playback process to the
playback device 110. After that, the BD-J module 1745 performs
the playback process of a title as usual. That is to say, the
application manager 1745A, in accordance with the application
management table 410 in the BD-J object, instructs the virtual
machine 1745B to start or terminate application programs.
Especially when a disc-unbound application program is being
executed, the application manager 1745A judges whether or not
to continue the execution. The virtual machine 1745B, in
accordance with an instruction from the application manager
1745A, starts or terminates application programs. Thus, the
BD-J module 1745, in accordance with application programs,
executes the playback process of the title that corresponds to
the item "first play" 303.
Step S25 04 : the two image playback state values indicate

anything other than the combination of States 1 and 2.
Accordingly, the BD-J module 1745 uses the application manager
1745A to cause the virtual machine 1745B to forcibly terminate
all application programs. After that, the process proceeds to
Step S2505.
Step S2505: the BD-J module 1745 causes the playback
unit 1660 to change the areas in the image memory 1810. More
specifically, when the two image playback state values indicate
switching from State 1 to State 3, from State 2 to State 3, from
State 1 to State 4, or from State 2 to State 4, the BD-J module
1745 first frees the cache area 1905 for BD-Live from the image
data area 1904, as shown in Fig. 19. Next, the BD-J module 1745
allocates the free area made available by the freeing, to the
IG plane memory area 1911, thereby doubling the capacity of the
IG plane memory area. On the other hand, when the two image
playback state values indicate switching in a reversed
direction such as switching from State 4 to State 2, the BD-J
module 1745 first frees half the IG plane memory area 1911. Next,
the BD-J module 1745 allocates the free area made available by
the freeing, to the image data area 1904 as the cache area 1905
for BD-Live. Furthermore, when the two image playback state
values indicate switching between States 3 and 4, the BD-J
module 1745 allocates the cache area for BD-Live in the IG plane
memory area 1911, or frees the cache area from the IG plane memory
area 1911. After that, the process proceeds to Step S2506.
Step S2506 : the BD-J module 1745 causes the AV playback
library 174 6 to update the current image playback state value
to the image playback state value 62 0 indicated by the BD-J
object. After that, the process proceeds to Step S2507.
Step S2507: the BD-J module 1745 switches the playback

device 110 to the state requested by the BD-J object. After
that, the BD-J module 1745 performs the playback process of a
title as usual. That is to say, the application manager 1745A,
in accordance with the application management table 410 in the
BD-J object, instructs the virtual machine 1745B to start or
terminate application programs. Especially when there is the
disc-unbound application program that was forcibly terminated
in Step S2504, the application manager 1745A judges whether or
not to resume the execution. The virtual machine 1745B, in
accordance with an instruction from the application manager
1745A, starts or terminates application programs. Thus, the
BD-J module 1745, in accordance with application programs,
executes the playback process of the title that corresponds to
the item "first play" 3 03.

When switching between titles causes switching from a
BD-J object to another BD-J object having a different image
playback state value, the BD-J module 1745 switches between the
states of the playback device 110 in accordance with the
different image playback state value. When States 1 and 3,
States 1 and 4, States 2 and 3, or States 2 and 4 are switched,
in the image memory 1810, the cache area 1905 is freed or
allocated and an area is exchanged between the image data area
and the IG plane memory area, as shown in Fig. 19. When States
3 and 4 are switched, in the image memory 1810, the cache area
for BD-Live and the image data area are changed in capacity.
On the other hand, disc-bound or disc-unbound application
programs are not terminated in general when a title is switched
to another. Accordingly, in this situation, there is a risk
that the application programs erroneously recognize and access

the areas in the image memory after the switching between titles
as the areas before the switching.
As described above, in the playback device 110 in
Embodiment 1 of the present invention, each time the BD-J object
is switched to another, the BD-J module 1745 compares the image
playback state value 620 presented by the BD-J object with the
current image playback state value. Furthermore, when the two
image playback state values indicates anything other than the
switching between States 1 and 2, the BD-J module 174 5 uses the
application manager 1745A to cause the virtual machine 1745B
to forcibly terminate all application programs. With this
structure, when the areas in the image memory 1810 are to be
changed, all the application programs are terminated in advance .
Therefore, there is no risk that the application programs
erroneously recognize and access the areas in the image memory
after the switching between titles as the areas before the
switching. In this way, the playback device 110 allows the
application programs to selectively use the 2-plane mode and
the BD-Live functions without malfunction. As a result of this,
the playback device 110 can play back digital contents including
graphics images with more expressive stereoscopic effects,
without increasing the capacity of the image memory.

(1) In Embodiment 1 of the present invention, when both
the left-view and right-view image data are present, in the
offset mode, the left-view image data is used. However, not
limited to this, the right-view image data may be used instead
of the left-view image data.
(2) The addition unit 1807 transmits left-view video
frames and right-view video frames alternately in pairs after

the synthesizing. As another method, when the display device
120 uses a lenticular lens to display 3D video images, the
addition unit 1807 may further synthesize each pair of a
left-view video frame and a right-view video frame into one
video frame, by using an embedded buffer memory. More
specifically, the addition unit 1807 temporarily stores in the
buffer memory the left-view video plane that has been
synthesized first. Subsequently, the addition unit 1807
synthesizes the right-view video plane, and further synthesizes
the resultant right-view video plane with the left-view video
frame stored in the buffer memory. In the synthesizing, the
left-view and right-view video planes are each divided into
small rectangular areas that are thin and long in a vertical
direction, and the small rectangular areas are arranged
alternately in the horizontal direction so as to re-constitute
one frame. In this way, the playback device of Embodiment 1
of the present invention is also compatible with display devices
that use a lenticular lens for displaying 3D video images.
(3) In the example shown in Fig. 24, in States 3 and 4,
the addition unit 18 07 realizes the offset mode and the 2-plane
mode in a selectable manner by using the two mode switches 2411
and 2412. Alternatively, in either or both of States 3 and 4,
the playback processes of 3D video images from the image data
may be limited to those in the 2-plane mode. Furthermore, when
there is no need to dynamically switch between the offset mode
and the 2-plane mode during a playback process of 3D video images,
each of States 3 and 4 may be divided into two states that are
separately specialized in the two modes. For example, the
states in which the original setting in State 3 is kept but the
playback processes of 3D video images from image data are fixed

to those in the offset mode and the 2-plane mode may be redefined
as States 3 and 5, respectively. In this case, the number of
types of image playback state values increases to six.
Furthermore, the switching between the offset mode and the
2-plane mode can be realized only by switching between titles.
(4) In States 3 and 4, the addition unit 1807 switches
between the offset mode and the 2-plane mode in accordance with
an instruction from the BD-J module 174 5 . For the instruction,
the register 1746A in the AV playback library 1746 may be used
as follows. First, a flag is set in the register 1746A. Next,
the BD-J module 174 5 turns off and on the flag when specifying
the offset mode and the 2-plane mode, respectively. On the
other hand, the addition unit 1807 operates in the offset mode
when the flag is off, and operates in the 2-plane mode when the
flag is on.
(5) When switching from the offset mode to the 2-plane
mode, the BD-J module 1745 may cause the rendering engine 1805
to copy a left-view image plane into a right-view image plane
in advance. Thereby, even if no data is written into the
right-view image plane due to a malfunction, no substantial
difference is generated between the graphics images played back
from the two planes. This prevents the graphics images from
bringing a sense of discomfort to viewers. Note that the
left-view image plane may be cleared, instead of copying the
left-view image plane into the right-view image plane.
(6) In Embodiment 1 of the present invention, the
playback processes of 3D video images from a BG plane and a PG
plane are both performed in the offset mode. Not limited to
this, application programs may cause the BD-J module 1745 to
generate both left-view BG plane and right-view BG plane so that

the playback process of 3D video images from the BG planes can
be performed in the 2-plane mode. Also, both left-view PG plane
and right-view PG plane may be multiplexed into an AV stream
file so that the playback process of 3D video images from the
PG planes can be performed in the 2-plane mode. These further
improve the stereoscopic effects of graphics images of
background and subtitles.
(7) At start-up immediately after power-on or the like,
allocation in the image memory has not yet been determined. In
this case, the BD-J module 174 5, in the process for switching
between states of the playback device 110, may skip Steps S2502
to S2504 among the steps shown in Fig. 25.
(8) The capacity of the cache area for BD-Live in State
3 is limited to an amount smaller than that in States 1 and 2.
Accordingly, when switching from State 1 or 2 to State 3 is
required by switching between titles, the BD-J module 1745 may
cause the display device 12 0 to display a warning screen thereon
before the switching. This enables the playback device 110 to
previously warn viewers of a risk of slowing down the response
of the BD-Live processes.
<>
A playback device in Embodiment 2 of the present
invention, in a playback process of 3D video images enables
application programs to select the HDMV mode or the BD-J mode
depending on embedded memory resources. Except for the
structure and function, the playback device in Embodiment 2 has
structures and functions similar to those of the playback device
in Embodiment 1. Accordingly, modified and extended
components of the playback device in Embodiment 2 with respect
to the playback device in Embodiment 1 will be explained below.

A description of the components of the playback device in
Embodiment 2 similar to those of the playback device in
Embodiment 1 can be found above in the explanation about
Embodiment 1.
The playback device in Embodiment 2 is classified as
either of two types, namely, a lower-cost version and a normal
version, depending on the size of the embedded memory resources .
A "lower-cost-version of playback device" refers to a playback
device equipped with smaller memory resources and thus can
execute the playback process of 3D video images only in the HDMV
mode. In the HDMV mode, in contrast to the BD-J mode, 3D video
images can be played back from only the bodies of the contents
recorded on the recording medium 100, but the graphics images
of interactive contents such as pop-up menus cannot be played
back. A "normal version of playback device" refers to a
playback device equipped with sufficiently large memory
resources and thus can execute the playback process of 3D video
images in both the HDMV mode and the BD-J mode. The BD-J module
1745 can notify application programs whether the playback
device in which the BD-J module 174 5 is incorporated is the
lower-cost version or the normal version, the application
programs being read from the recording medium 100 at the
switching between titles.
Fig. 26 is a flowchart of an event handling performed
by an application program. This event handling is started when
the user operation detection module 1702 receives a
notification from the operation unit 1620.
Step S2601: the user operation detection module 1702
determines the type of the event indicated by the notification
from the operation unit 1620, and then sends an operation signal

indicating the type of the event to the mode management module
1743 . In the mode management module 1743, the dispatcher 1743A
passes the operation signal to the BD-J module 1745. The BD-J
module 1745 interprets the operation signal and notifies the
application program of the meaning of the operation signal. The
application program judges whether or not the meaning of the
operation signal indicates a request for a 3D image playback
process. When the judgment is negative, the process proceeds
to Step S2602; and when the judgment is affirmative, the process
proceeds to Step S2603.
Step S2602: the user operation does not indicate any
request for 3D image playback process, and accordingly the
application program performs a normal event handling.
[0214] Step S2603: the user operation indicates a request for
a 3D image playback process, and accordingly the application
program inquires of the BD-J module 1745 whether or not the
playback device is the lower-cost version. When the answer to
the inquiry is negative, the process proceeds to Step S2 6 04;
and when the answer is affirmative, the process proceeds to Step
S2605.
Step S2604: the playback device is the normal version,
and accordingly the 3D image playback process can be executed
in the BD-J mode. Hence, the application program starts the
3D image playback process in the BD-J mode.
[0216] Step S2605: the playback device is the lower-cost
version, and accordingly the 3D image playback process can be
executed only in the HDMV mode. Hence, the application program
causes the BD-J module 1745 to switch from the title for the
BD-J mode to another title for the HDMV mode. With the switching
between the titles, the module to execute the playback process

changes from the BD-J module 1745 to the HDMV module 1744. In
the example shown in Fig. 3, the 2D image playback process
executed in accordance with the first BD-J object BDJ0-2D
assigned to the "title 2" is changed to the 3D image playback
process executed in accordance with the second movie object
MV0-3D assigned to the "title 3". When the 3D image playback
process ends, the title to be processed is changed back to the
original title for BD-J mode, and the module to execute the
playback process changes back from the HDMV module 1744 to the
BD-J module 1745.
As described above, the playback device in Embodiment
2 of the present invention, regardless of whether it is the
lower-cost version or the regular version, enables the
application programs read from the recording medium 100 to
execute the 3D-image playback processes reliably. This can
reduce the loads on the authoring of the application programs.

<>
When UDF is used as the file system of the BD-ROM disc
100, the volume area 122 shown in Fig. 2 includes a directory
area, a recording area for a file set descriptor, and a recording
area for a terminating descriptor. The "directory area" is
ordinarily a plurality of areas, each of which is a recording
area for data constituting a single directory. The "file set
descriptor" indicates a logical block number (LBN) of a sector
that stores the file entry of the root directory. The
"terminating descriptor" indicates the termination of the file
set descriptor.
Each directory area shares a common data structure. In
particular, each directory area has a file entry, a directory

file, and recording areas for each subordinate file.
The "file entry" includes a descriptor tag, an ICB tag,
and an allocation descriptor. The "descriptor tag" indicates
that the data that includes the descriptor tag is the file entry.
For example, when a descriptor tag has a value of "261," that
data is a file entry. The "ICB tag" indicates attribute
information of the file entry itself. The "allocation
descriptor" indicates the LBN of the sector in which the
directory file belonging to the same directory area is recorded.
The "directory file" includes the file identification
descriptor of a subordinate directory and the file
identification descriptor of a subordinate file. The "file
identification descriptor of a subordinate directory" is
reference information used for accessing the subordinate
directory located immediately below the directory recorded in
the directory area. In particular, this file identification
descriptor includes identification information of the
subordinate directory, the length of the directory name, a file
entry address, and the actual directory name. Here, the file
entry address indicates the LBN of the sector on which the file
entry of the subordinate directory is recorded. The "file
identification descriptor of a subordinate file" is reference
information for accessing the subordinate file located
immediately below the directory recorded in the directory area.
This file identification descriptor includes identification
information of the subordinate file, the length of the file name,
a file entry address, and the actual file name. Here, the file
entry address indicates the LBN of the file entry of the
subordinate file. By tracing the file identification
descriptors of subordinate directories/files, the file entries

of the subordinate directories/files can be sequentially found,
starting from the file entry of the root directory.
The "subordinate file" includes the file entry and the
body of the subordinate file located immediately below the
directory recorded on the directory area. The "file entry"
includes a descriptor tag, an ICB tag, and allocation
descriptors. The "descriptor tag" indicates that the data that
includes the descriptor tag is a file entry. The "ICB tag"
indicates attribute information of the file entry itself. The
"allocation descriptors" indicate the arrangement of the
Extents constituting the body of the subordinate file. Here,
"Extent" refers to a data sequence in which logical addresses
are continuous. Each allocation descriptor is assigned to one
of the Extents . Therefore, when the subordinate file is divided
into a plurality of Extents, the file entry includes a plurality
of allocation descriptors . More specif ically, each allocation
descriptor includes the size of an Extent and an LBN.
Furthermore, the two most significant bits of each allocation
descriptor indicate whether an Extent is actually recorded at
the sector for that LBN. More specifically, when the two most
significant bits indicate "0, " an Extent has been allocated to
the sector and has been actually recorded therein. When the
two most significant bits indicate "1," an Extent has been
allocated to the sector but has not been yet recorded therein.
The logical addresses of the extents constituting each file can
be found by referencing the allocation descriptors of the file
entry of the file.
Like the above-described file system employing the UDF,
when each file recorded on the volume area 122 is divided into
a plurality of Extents, the file system for the volume area 122

also generally stores the information showing the locations of
the Extents, as with the above-mentioned allocation descriptors,
in the volume area 122. By referencing the information, the
location of each Extent, particularly the logical address
thereof, can be found.
«Data distribution via broadcasting or communication
circuit»
The recording medium according to Embodiment 1 of the
present invention may be, in addition to an optical disc, a
general removable medium available as a package medium, such
as a portable semiconductor memory device including an SD memory
card. Also, the embodiments describe an example of an optical
disc in which data has been recorded beforehand, namely, a
conventionally available read-only optical disc such as a
BD-ROM or a DVD-ROM. However, the embodiments of the present
invention are not limited to these. For example, when a
terminal device writes a 3D video image content that has been
distributed via broadcasting or a network into a conventionally
available rewritable optical disc such as a BD-RE or a DVD-RAM,
arrangement of the Extents according to the above-described
embodiments may be used. Here, the terminal device may be
incorporated in a playback device, or may be a device different
from the playback device.
<>
The following describes a data read unit of a playback
device in the case where a semiconductor memory card is used,
instead of the optical disc, as the recording medium in the
embodiments of the present invention.
A part of the playback device that reads data from an
optical disc is composed of an optical disc drive, for example.

Compared with this, a part of the playback device that reads
data from a semiconductor memory card is composed of a dedicated
interface . In more detail, the playback device is provided with
a card slot, and the dedicated interface is implemented in the
card slot. When the semiconductor memory card is inserted into
the card slot, the semiconductor memory card is electrically
connected with the playback device via the dedicated interface.
Furthermore, the data is read from the semiconductor memory card
to the playback device via the dedicated interface.
<>
Here, the mechanism for protecting copyright of data
recorded on a BD-ROM disc is described as an assumption for the
supplementary explanation that follows it.
From a standpoint, for example, of improving copyright
protection or confidentiality of data, there are cases in which
a part of the data recorded on the BD-ROM is encrypted. The
encrypted data is, for example, a video stream, an audio stream,
or other stream. In such a case, the encrypted data is decrypted
in the following manner.
A device key, which is part of data necessary for
generating a "key" to be used for decrypting the encrypted data
recorded on the BD-ROM disc, is recorded in the playback device
beforehand. On the other hand, an MKB (Media Key Block) and
encrypted data of the "key" itself, namely, an encrypted title
key are recorded on the BD-ROM disc, where the MKB is another
part of the data necessary for generating the "key" . The device
key, the MKB, and the encrypted title key are associated with
one another, and each are further associated with a volume ID
which is an identifier written in a BCA 201 recorded on the BD-ROM

disc 100 shown in Fig. 2. When the combination of the device
key, the MKB, the encrypted title key, and the volume ID is not
correct, the encrypted data cannot be decrypted. In other words,
only when the combination is correct, the above-mentioned
"key," namely the title key, can be generated. Specifically,
the encrypted title key is first decrypted using the device key,
the MKB, and the volume ID. Only when the title key can be
obtained as a result of the decryption, the encrypted data can
be decrypted using the title key as the above-mentioned "key."
When a playback device tries to play back the encrypted
data recorded on the BD-ROM disc, the playback device cannot
play back the encrypted data unless the playback device stores
a device key that is associated beforehand with the encrypted
title key, the MKB, the device, and the volume ID recorded on
the BD-ROM disc . This is because a key necessary for decrypting
the encrypted data, namely a title key, can be obtained only
by decrypting the encrypted title key based on the correct
combination of the MKB, the device key, and the volume ID.
In order to protect the copyright of at least one of
a video stream and an audio stream that are to be recorded on
a BD-ROM disc, a stream to be protected is encrypted using the
title key, and the encrypted stream is recorded on the BD-ROM
disc. Next, a key is generated based on the combination of the
MKB, the device key, and the volume ID, and the title key is
encrypted using the key so as to be converted to an encrypted
title key. Furthermore, the MKB, the volume ID, and the
encrypted title key are recorded onto the BD-ROM disc. Only
a playback device storing the device key to be used for
generating the above-mentioned key can decrypt the encrypted
video stream and/or the encrypted audio stream recorded on the

BD-ROM disc using a decoder. In this manner, it is possible
to protect the copyright of the data recorded on the BD-ROM disc .
The above-described mechanism for protecting the
copyright of the data recorded on the BD-ROM disc is applicable
to a recording medium other than the BD-ROM disc. For example,
the mechanism is applicable to a readable/rewritable
semiconductor memory device, in particular to a portable
semiconductor memory card such as an SD card.
<>
[0256] The embodiments of the present invention is based on
the assumption that an AV stream file and a playlist file are
recorded on a BD-ROM disc using the prerecording technique of
the authoring system, and the recorded AV stream file and
playlist file are provided to users. Alternatively, it may be
possible to record, by performing real-time recording, the AV
stream file and the playlist file in a rewritable recording
medium such as a BD-RE disc, a BD-R disc, a hard disk, or a
semiconductor memory card (hereinafter, "BD-RE disc or the
like") , and provide the user with the recorded AV stream file
and playlist file. In such a case, the AV stream file may be
a transport stream that has been obtained as a result of
real-time decoding of an analog input signal performed by a
recording device. Alternatively, the AV stream file may be a
transport stream obtained as a result of partialization of a
digitally input transport stream performed by the recording
device.
[0257] The recording device performing real-time recording
includes a video encoder, an audio encoder, a multiplexer, and
a source packetizer. The video encoder encodes a video signal
to convert it into a video stream. The audio encoder encodes
an audio signal to convert it into an audio stream. The
multiplexer multiplexes the video stream and audio stream to
convert them into a digital stream in the MPEG-2 TS format. The
source packetizer converts TS packets in the digital stream in
MPEG-2 TS format into source packets. The recording device

stores each source packet in the AV stream file and writes the
AV stream file on the BD-RE disc or the like.
In parallel with the processing of writing the AV
stream file, the control unit of the recording device generates
a clip information file and a playlist file in the memory and
writes the files on the BD-RE disc or the like. Specifically,
when a user requests performance of recording processing, the
control unit first generates a clip information file in
accordance with an AV stream file and writes the file on the
BD-RE disc or the like. In such a case, each time a head of
a GOP of a video stream is detected from a transport stream
received from outside, or each time a GOP of a video stream is
generated by the video encoder, the control unit acquires a PTS
of an I picture positioned at the head of the GOP and an SPN
of the source packet in which the head of the GOP is stored.
The control unit further stores a pair of the PTS and the SPN
as one entry point in an entry map of the clip information file.
Here, an "is_angle_change" flag is added to the entry point.
The is_angle_change flag is set to "on" when the head of the
GOP is an IDR picture, and "off" when the head of the GOP is
not an IDR picture. In the clip information file, stream
attribute information is further set in accordance with an
attribute of a stream to be recorded. In this manner, after
writing the AV stream file and the clip information file into
the BD-RE disc or the like, the control unit generates a playlist
file using the entry map in the clip information file, and writes
the file onto the BD-RE disc or the like.
<>
The playback device according to the embodiments of the
present invention may write a digital stream recorded on the

BD-ROM disc 100 on another recording medium via a managed copy.
Here, managed copy refers to a technique for permitting copy
of a digital stream, a playlist file, a clip information file,
and an application program from a read-only recording medium
such as a BD-ROM disc to a rewritable recording medium only in
the case where authentication with the server via communication
succeeds. Here, the rewritable recording medium may be a
rewritable optical disc such as a BD-R, aBD-RE, a DVD-R, aDVD-RW,
and a DVD-RAM, and a portable semiconductor memory device such
as a hard disk, an SD memory card, a Memory Stick (TM) , a Compact
Flash (TM) , a Smart Media (TM) , and a Multimedia Card (TM) . A
managed copy allows for limitation of the number of backups of
data recorded on a read-only recording medium and for charging
for backups.
When a managed copy is performed from a BD-ROM disc to
a BD-R disc or a BD-RE disc and the two discs have an equivalent
recording capacity, the bit streams recorded on the original
disc may be copied in order as they are.
If a managed copy is performed between different types
of recording media, a trans code needs to be performed. Here,
a "trans code" refers to processing for adjusting a digital
stream recorded on the original disc to the application format
of a recording medium that is the copy destination. For example,
the trans code includes the process of converting an MPEG-2 TS
format into an MPEG-2 program stream format and the process of
reducing a bit rate of each of a video stream and an audio stream
and re-encoding the video stream and the audio stream. During
the trans code, an AV stream file, a clip information file, and
a playlist file need to be generated in the above-mentioned
real-time recording.

<>
Among the data structures in the embodiments of the
present invention, a repeated structure "there is a plurality
of pieces of information having a predetermined type" is defined
by describing an initial value of a control variable and a cyclic
condition in a "for" sentence. Also, a data structure "if a
predetermined condition is satisfied, predetermined
information is defined" is defined by describing, in an "if"
sentence, the condition and a variable to be set at the time
when the condition is satisfied. In this manner, the data
structure described in the embodiments is described using a high
level programming language. Accordingly, the data structure
is converted by a computer into a computer readable code via
the translation process performed by a compiler, which includes
"syntax analysis, " "optimization, " "resource allocation, " and
"code generation, " and the data structure is then recorded on
the recording medium. By being described in a high level
programming language, the data structure is treated as a part
other than the method of the class structure in an
object-oriented language, specifically, as an array type member
variable of the class structure, and constitutes a part of the
program. In other words, the data structure is substantially
equivalent to a program. Therefore, the data structure needs
to be protected as a computer related invention.
<>
When a playlist file and an AV stream file are recorded
onto a recording medium, a playback program is recorded onto
the recording medium in an executable format. The playback
program makes the computer play back the AV stream file in

accordance with the playlist file. The playback program is
loaded from a recording medium to a memory device of a computer
and is then executed by the computer. The loading process
includes a compile process or link process . By these processes,
the playback program is divided into a plurality of sections
in the memory device. The sections include a text section, a
data section, a bss section, and a stack section. The text
section includes a code array of the playback program, an
initial value, and non-rewritable data. The data section
includes variables with initial values and rewritable data. In
particular, the data section includes a file, recorded on the
recording device, that can be accessed at any time. The bss
section includes variables having no initial value. The data
included in the bss section is referenced in accordance with
commands indicated by the code in the text section. During the
compile process or link process, an area for the bss section
is ensured in the computer's internal RAM. The stack section
is a memory area temporarily ensured as necessary. During each
of the processes by the playback program, local variables are
temporarily used. The stack section includes these local
variables. When the program is executed, the variables in the
bss section are initially set at zero, and the necessary memory
area is ensured in the stack section.
As described above, the playlist file and the clip
information file are already converted on the recording medium
into computer readable code. Accordingly, at the time of
execution of the playback program, these files are each managed
as "non-rewritable data" in the text section or as a "file
accessed at any time" in the data section. In other words, the
playlist file and the clip information file are each included

as a compositional element of the playback program at the time
of execution thereof . Therefore, the playlist file and the clip
information file fulfill a greater role in the playback program
than mere presentation of data.
<>
A playback device according to the embodiments of the
present invention includes middleware, a system LSI, and
hardware other than the system LSI. The playback device further
includes an interface for the middleware, an interface between
the middleware and the system LSI, an interface between the
middleware and other hardware, and a user interface. When these
elements are incorporated in a playback device, they operate
in cooperation with one another. As a result, each element
provides the playback device with a unique function. By
appropriately defining the interface for the middleware and the
interface between the middleware and the system LSI, it is
possible to develop the user interface, middleware, and system
LSI in the playback device independently, in parallel, and
efficiently. Note that in each interface, there is generally
a variety of such appropriate definitions.
[Industrial Applicability]
The present invention relates to a technology for
playing back a stereoscopic video image, and as described above,
changes the image data area after forcibly terminating the
application program. It is therefore apparent that the present
invention is industrially applicable.
[Reference Signs List]

1810 image memory
1901 IG plane memory area in the states 1 and 2
1902 PG plane memory area in the states 1 and 2
1903 BG plane memory area in the states 1 and 2
1904 image data area in the states 1 and 2
1905 cache area for the BD-Live in the states 1 and 2

1911 IG plane memory area in the states 3 and 4
1912 PG plane memory area in the states 3 and 4
1913 BG plane memory area in the states 3 and 4
1914 image data area in the states 3 and 4

We Claim:
1. A playback device comprising:
a reading unit operable to read an application program,
image data, a video stream, and an application management file
from a recording medium;
a virtual machine unit operable to execute the
application program;
a memory unit including an image data area for storing
the image data;
a playback unit operable to play back video data with use
of the image data and the video stream in accordance with the
application program; and
a management unit operable to, in accordance with the
application management file, instruct the virtual machine unit
to start and terminate the application program, and instruct
the memory unit to change the image data area, the management
unit further operable to cause the virtual machine unit to
forcibly terminate the application program before instructing
the memory unit to change the image data area even when the
application management file specifies the continuous execution
of the application program.
2. The playback device of Claim 1 further comprising:
an image decoder operable to expand the image data into
the image data area; and
a rendering engine operable to perform a calculation for
a graphics process on the image data, wherein
the management unit, in accordance with the application
management file, instructs the image decoder to expand the image

data, and instructs the rendering engine to perform the
calculation.
3. The playback device of Claim 1, wherein,
after the recording medium is removed from the reading
unit, when the reading unit detects an insertion of a new
recording medium while the virtual machine unit continues to
execute the application program, the management unit causes the
reading unit to read a new application management file from the
new recording medium, and instructs the memory unit to change
the image data area in accordance with the new application
management file.
4. The playback device of Claim 1 further comprising
a network interface unit operable to download data of a
browser screen from a server device on an external network,
wherein
the playback unit is operable in a live playback mode to
synthesize the browser screen with a video image played back
from the recording medium, and
the changing of the image data area includes one of
allocating a cache area in the image data area and freeing the
cache area from the image data area, the cache area being for
temporarily storing data of a current browser screen and a
previous browser screen.
5. The playback device of Claim 4, wherein,
when the image data includes left-view image data and
right-view image data for a 3D menu, the changing of the image
data area includes freeing the cache area from the image data

area and using a free area available by freeing the cache area
to store the left-view image data and the right-view image data.
6 . The playback device of Claim 5 , wherein the management unit,
in accordance with the application program,
accepts from a user an instruction specifying whether or
not the 3D menu should be played back,
causes the virtual machine unit to check a capacity of
the memory unit when the instruction specifies that the 3D menu
should be played back,
provides the memory unit with an instruction when the
capacity of the memory unit is larger than a predetermined
threshold value, the instruction being to free the cache area
and use the free area to store the left-view image data and the
right-view image data, and
disables playback of the 3D menu when the capacity of the
memory unit is smaller than the predetermined threshold value.
7. A playback method comprising the steps of:
reading an application program, image data, a video
stream, and an application management file from a recording
medium;
executing the application program;
storing the image data into an image data area in a memory-
unit;
playing back video data with use of the image data and
the video stream in accordance with the application program;
forcibly terminating the application program even when
the application management file specifies the continuous
execution of the application program; and

changing the image data area after the termination of the
application program.
8 . A program for causing a playback device to execute the steps
of:
reading an application program, image data, a video
stream, and an application management file from a recording
medium;
executing the application program;
storing the image data into an image data area in a memory
unit;
playing back video data with use of the image data and
the video stream in accordance with the application program;
forcibly terminating the application program even when
the application management file specifies the continuous
execution of the application program; and
changing the image data area after the termination of the
application program.
9. An integrated circuit implemented in a playback device,
the playback device including:
a reading unit operable to read an application program,
image data, a video stream, and an application management file
from a recording medium; and
a playback unit operable to play back video data with use
of the image data and the video stream,
the integrated circuit comprising:
a virtual machine unit operable to execute the
application program read by the reading unit from the recording
medium;

a memory unit including an image data area for storing
the image data; and
a management unit operable to refer to the application
management file read by the reading unit from the recording
medium, and in accordance with the application management file,
instruct the virtual machine unit to start and terminate the
application program and instruct the memory unit to change the
image data area, the management unit further operable to cause
the virtual machine unit to forcibly terminate the application
program before instructing the memory unit to change the image
data area even when the application management file specifies
the continuous execution of the application program.

The reading unit reads an application program, image data,
a video stream, and an application management file from a
recording medium. The virtual machine unit executes the
application program. The memory unit includes an image data
area for storing the image data. The playback unit plays back
video data with use of the image data and the video stream in
accordance with the application program. The management unit,
in accordance with the application management file, instructs
the virtual machine unit to start and terminate the application
program and instructs the memory unit to change the image data
area. Before instructing the memory unit to change the image
data area, the management unit causes the virtual machine unit
to forcibly terminate the application program even when the
application management file specifies the continuous execution
of the application program.