FORM 2
The Patents Act, 1970 (39 of 1970)
COMPLETE SPECIFICATION
(See Section 10, Rule 13)
"INFORMATION REPRODUCING APPARATUS AND METHOD AND
COMPUTER PROGRAM"

PIONEER CORPORATION, a corporation organized and existing under the laws of Japan, having its Registered Office at 4-1, Meguro 1-chome, Meguro-ku,Tokyo 153-8654,Japan.

DESCRIPTION
INFORMATION REPRODUCING APPARATUS AND METHOD, AND COMPUTER PROGRAM 5
Technical Field
The present invention relates to an information reproducing apparatus for and method of performing reproduction on an information recording medium, such as an optical disc, and a computer program which 10 makes a computer function as such an information reproducing apparatus.
Background Art
As a next-generation optical disc of a DVD, which is becoming popular, a Blu-ray Disc is under development. In the Blu-ray Disc, a blue laser beam
15 is used to record and reproduce record data, wherein the blue laser beam has a shorter wavelength than that of a red laser beam, which is used to record and reproduce the record data on a DVD. Moreover, by shortening the pitch of tracks formed on a recording surface, the Blu-ray Disc attains a recording capacity of about 23GB in a signal recording layer (refer to patent documents
20 1 to 3).
On the other hand, a sub-picture, such as a small window, can be displayed with it superimposed on a main picture (in other words, superimposed on one portion of the main picture), such as a movie, recorded on the optical disc described above. As the sub-picture, there are a
25 sub-picture of a Synchronous type (hereinafter referred to as a "Sync type") and a sub-picture of an Asynchronous type (hereinafter referred to as an
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"Async type"), in accordance with its display method. In the sub-picture of the Sync type, a display start time point and a display end time point are set in advance with respect to a reproduction time point of the main picture. On the other hand, in the sub-picture of the Async type, the display can be 5 arbitrarily started, in accordance with a user's instruction or the like.
In this case, in order to identify the sub-picture currently selected as the display target from a plurality of types of sub-pictures recorded on the optical disc, a stream number of the selected sub-picture is held in a status register or the like. The stream number held in the status register continues 10 to be held in the status register as long as a new sub-picture is not selected. Patent document l: Japanese Patent Application Laid Open NO. 2004-304767 Patent document 2- Japanese Patent Application Laid Open NO. 2004-328450 Patent document 3: Japanese Patent Application Laid Open NO. 2005-269595
15 Disclosure of Invention
Subject to be Solved by the Invention
In case of the sub-picture of the Sync type, even if the stream number continues to be held in the status register, there is no particular disadvantage in displaying the sub-picture because the display start time point and the
20 display end time point are set in advance. However, in case of the sub-picture of the Async type, if the stream number continues to be held, the following technical problem can occur. For example, it is assumed that the main picture is rewound or the like while the sub-picture of the Async type is displayed. At this time, even if a reproduction time point at which the
25 rewind is ended is a time point at which the display of the sub-picture is not originally desired, the sub-picture is displayed at an unexpected reproduction
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time point because the stream number is held in the status register and
because the sub-picture is of the Async type in which the display can be
started from an arbitrary reproduction time point, which is the technical
problem that can occur.
5 The subject to be solved by the present invention includes the
aforementioned problem as an example. It is therefore an object of the present invention to provide an information reproducing apparatus and method, which can preferably display a sub-picture which is superimposed and displayed on a main picture, and a computer program which makes a 10 computer function as such an information recording apparatus.
Means for Solving the Subject
The above object of the present invention can be achieved by an information reproducing apparatus provided with: a displaying device for
15 displaying a main picture and a sub-picture of a first type, which is superimposed and displayed on the main picture and whose display can be started at a desired reproduction time point on a reproduction time axis of the main picture; a storing device for storing an identification number of the sub-picture of the first type selected to be superimposed and displayed on the
20 main picture; a first controlling device for controlling the storing device to destroy the identification number of the sub-picture of the first type, if a current reproduction time point of the main picture is beyond a range of reproduction time points in which the sub-picture of the first type is to be displayed; and a second controlling device for controlling the storing device to
25 continue to store the identification number of the sub-picture of the first type, if the current reproduction time point of the main picture is not beyond the
3

range of reproduction time points in which the sub-picture of the first type is to be displayed.
The above object of the present invention can be also achieved by an information reproducing method in an information reproducing apparatus 5 provided with: a displaying device for displaying a main picture and a sub-picture of a first type, which is superimposed and displayed on the main picture and whose display can be started at a desired reproduction time point on a reproduction time axis of the main picture; and a storing device for storing an identification number of the sub-picture of the first type selected to
10 be superimposed and displayed on the main picture, the information reproducing method provided with: a first controlling process of controlling the storing device to destroy the identification number of the sub-picture of the first type, if a current reproduction time point of the main picture is beyond a range of reproduction time points in which the sub-picture of the
15 first type is to be displayed and a second controlling process of controlling the storing device to continue to store the identification number of the sub-picture of the first type, if the current reproduction time point of the main picture is not beyond the range of reproduction time points in which the sub-picture of the first type is to be displayed.
20 The above object of the-present invention can be also achieved by a
computer program for reproduction control and for controlling a computer provided in the information reproducing apparatus of the present invention, the computer program making the computer function as at least one portion of the first controlling device and the second controlling device.
25 These effects and other advantages of the present invention will
become more apparent from the embodiments explained below.
4

Brief Description of Drawings
[FIG. 1] FIG. 1 is a block diagram conceptually showing the basic structure
of an information recording / reproducing apparatus in an example. 5 [FIG. 2] FIG. 2 is a data structure diagram conceptually showing the logical
structure of a title table.
[FIG. 3] FIG. 3 is a data structure diagram conceptually showing the logical
structure of a play list.
[FIG 4] FIG. 4 is a cross sectional view showing a new optical disc and a 10 graph showing tracking polarity.
[FIG. 5] FIG. 5 is a data structure diagram conceptually showing the logical
structure of the play list in employing PinP in which a second picture, which
is a sub-picture, is superimposed and displayed on at least one portion of a
first picture, which is a main picture. 15 [FIG. 6] FIG. 6 is a timing chart conceptually showing a flow of the display
of the first picture and the second picture along a time axis when the second
picture of a Sync type is superimposed and displayed on the first picture.
[FIG. 7] FIG. 7 is a timing chart conceptually showing a flow of the display
of the first picture and the second picture along the time axis when the second 20 picture of the Sync type is superimposed and displayed on the first picture.
[FIG. 8] FIG. 8 is a plan view conceptually showing the second picture which
is superimposed and displayed on the first picture.
[FIG. 9] FIG. 9 is a flow chart conceptually showing a flow of the operation
of the information recording / reproducing apparatus in the example. 25 [FIG. 10] FIG. 10 is a timing chart conceptually showing one flow of the
display of the first picture and the second picture along the time axis, if a user
5

performs a rewind operation when the second picture of an Async type is superimposed and displayed on the first picture.
[FIG. 11] FIG. 11 is a timing chart conceptually showing another flow of the display of the first picture and the second picture along the time axis, if the user performs the rewind operation when the second picture of the Async type is superimposed and displayed on the first picture.
Description of Reference Codes
10 title table
12 pointer to play list
30 play list
31 play item 100 optical disc
200 information recording / reproducing apparatus
352 optical pickup
353 signal recording / reproducing device

354, 359 CPU
355, 360 memory
Best Mode for Carrying Out the Invention
Hereinafter, the best mode for carrying out the present invention will be explained in embodiments of the information reproducing apparatus and method, and the computer program of the present invention with reference to the drawings.
(Embodiment of Information Reproducing Apparatus)
An embodiment of the information reproducing apparatus of the
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present invention is provided with: a displaying device for displaying a main picture and a sub-picture of a first type, which is superimposed and displayed on the main picture and whose display can be started at a desired reproduction time point on a reproduction time axis of the main picture,' a 5 storing device for storing an identification number of the sub-picture of the first type selected to be superimposed and displayed on the main picture; a first controlling device for controlling the storing device to destroy the identification number of the sub-picture of the first type, if a current reproduction time point of the main picture is beyond a range of reproduction
10 time points in which the sub-picture of the first type is to be displayed! and a second controlling device for controlling the storing device to continue to store the identification number of the sub-picture of the first type, if the current reproduction time point of the main picture is not beyond the range of reproduction time points in which the sub-picture of the first type is to be
15 displayed.
According to the embodiment of the information reproducing apparatus of the present invention, the main picture, such as a movie, can be displayed on a display or the like by the operation of the displaying device. Moreover, by the operation of the displaying device, the sub-picture of the
20 first type can be displayed with it superimposed on the main picture (in other words, superimposed on one portion of the main picture). The sub-picture of the first type is a sub-picture whose display can be started at the desired reproduction time point on the reproduction time axis of the main picture, and it is referred to as e.g. a sub-picture of an Async type. That is, the
25 sub-picture of the first type is a sub-picture whose reproduction time point to start the display is not set in advance, and which can be displayed at an
7

arbitrary reproduction time point in accordance with a user's instruction.
At this time, the identification number of the sub-picture which is the
display target (for example, which is selected as the display target by the user
or the like) is stored in the storing device. The displaying device
5 superimposes and displays the sub-picture, which is specified by the
identification number stored in the storing device, on the main picture.
In particular in the embodiment, by the operation of the first controlling device, the identification number of the sub-picture stored in the storing device is destroyed if the current reproduction time point of the main
10 picture is beyond the range of reproduction time points for the sub-picture of the first type. More specifically, in the case that a reproduction time point to start the display of the sub-picture of the first type is T1 and a reproduction time point to end the display of the sub-picture of the first type is T2, if a current reproduction time point T is not within the range of Tl to T2, the
15 identification number of the sub-picture stored in the storing device is destroyed.
On the other hand, if the current reproduction time point of the main picture is not beyond the range of reproduction time points of the sub-picture of the first type, the identification number of the sub-picture stored in the
20 storing device continues to be stored by the operation of the second controlling device. More specifically, in the case that the reproduction time point to start the display of the sub-picture of the first type is Tl and the reproduction time point to end the display of the sub-picture of the first type is T2, if the current reproduction time point T is within the range of Tl to T2, the
25 identification number of the sub-picture stored in the storing device continues to be stored by the operation of the second controlling device.
8

For example, it is assumed that the main picture is rewound, fast-forwarded, or the like in the condition that the main picture is displayed while the sub-picture of the first type superimposed thereon. In this case, if a reproduction time point at which the rewind or the fast-forwarding is ended 5 is beyond the range of reproduction time points in which the sub-picture of the first type is to be displayed, the sub-picture of the first type is not displayed with it superimposed on the main picture when the main picture is reproduced after the rewind or the fast-forwarding is ended. On the other hand, if the reproduction time point at which the rewind or the
10 fast-forwarding is ended is within the range of reproduction time points in which the sub-picture of the first type is to be displayed, the sub-picture of the first type is superimposed and displayed on the main picture when the main picture is reproduced after the rewind or the fast-forwarding is ended.
As described above, on the basis of the reproduction time point of the
15 main picture and the range of reproduction time points of the sub-picture of the first type, it is possible to preferably suppress or eliminate such a disadvantage that the sub-picture of the first type is displayed at an unexpected reproduction time point or undesired reproduction time point. That is, it is possible to preferably display the sub-picture that is
20 superimposed and displayed on the main picture.
In one aspect of the information reproducing apparatus of the present invention, the first controlling device may control the storing device to destroy the identification number of the sub-picture of the first type, if the current reproduction time point of the main picture is beyond the range of
25 reproduction time points in which the sub-picture of the first type is to be displayed, after the sub-picture of the first type is superimposed and
9

displayed on the main picture.
By virtue of such construction, it is possible to preferably suppress or eliminate such a disadvantage that the sub-picture of the first type is displayed at an unexpected reproduction time point or undesired 5 reproduction time point.
In another aspect of the information reproducing apparatus of the present invention, the second controlling device may control the storing device to continue to store the identification number of the sub-picture of the first type, if the current reproduction time point of the main picture is not
10 beyond the range of reproduction time points in which the sub-picture of the first type is to be displayed, after the sub-picture of the first type is superimposed and displayed on the main picture.
By virtue of such construction, it is possible to preferably suppress or eliminate such a disadvantage that the sub-picture of the first type is
15 displayed at an unexpected reproduction time point or undesired reproduction time point.
In another aspect of the information reproducing apparatus of the present invention, the displaying device displays a sub-picture of a second type which is superimposed and displayed on the main picture and whose
20 reproduction time point to start the display is set in advance with respect to the reproduction time axis of the main picture, the storing device stores the identification number of the sub-picture of the first type or the sub-picture of the second type, which is selected to be superimposed and displayed on the main picture, and the information reproducing apparatus is further provided
25 with a third controlling device for controlling the storing device to continue to store the identification number of the sub-picture of the second type, if the
10

sub-picture of the second type is superimposed and displayed on the main
picture.
According to this aspect, by the operation of the displaying device, the sub-picture of the second type, which is different from the sub-picture of the 5 first type, can be displayed with it superimposed on the main picture (in other words, superimposed on one portion of the main picture). The sub-picture of the second type is a sub-picture whose reproduction time point to start the display (and moreover, whose reproduction time point to end the display) is set in advance with respect to the reproduction time axis of the main picture,
10 and it is referred to as e.g. a sub-picture of an Sync type. For the sub-picture of the second type, as in the sub-picture of the first type, the identification number of the sub-picture, which is the display target, is stored in the storing device.
Incidentally, it is preferably one sub-picture that is superimposed and
15 displayed on the main picture. That is, if the sub-picture of the first type is superimposed and displayed on the main picture, the sub-picture of the second type is preferably not displayed. In the same manner, if the sub-picture of the second type is superimposed and displayed on the main picture, the sub-picture of the first type is preferably not displayed.
20 Moreover, if one of a plurality of sub-pictures of the first type is superimposed and displayed on the main picture, another one of the plurality of sub-pictures of the first type is preferably not displayed. In the same manner, if one of a plurality of sub-pictures of the second type is superimposed and displayed on the main picture, another one of the plurality
25 of sub-pictures of the second type is preferably not displayed.
Then, if the sub-picture of the second type is superimposed and
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displayed on the main picture, the identification number of the sub-picture stored in the storing device continues to be stored by the operation of the third controlling device. That is, since the reproduction time point or the like to start the display of the sub-picture of the second type is set in advance, even if 5 the identification number continues to be stored as it is, there is no possibility that the sub-picture of the second type is displayed at an unexpected reproduction time point or undesired reproduction time point. Therefore, if the sub-picture of the second type is superimposed and displayed on the main picture, the identification number continues to be stored, and the sub-picture
10 of the second type is displayed automatically or in accordance with a user's instruction.
In an aspect of the information reproducing apparatus in which the sub-picture of the second type is displayed, as described above, it may be further provided with a first judging device for judging whether the
15 sub-picture of the first type is selected as the sub-picture to be superimposed and displayed on the main picture or the sub-picture of the second type is selected as the sub-picture to be superimposed and displayed on the main picture.
By virtue of such construction, while preferably distinguishing
20 between the sub-picture of the first type and the sub-picture of the second type, it is possible to preferably suppress or eliminate such a disadvantage that the sub-picture of the first type is displayed at an unexpected reproduction time point or undesired reproduction time point.
In another aspect of the information reproducing apparatus of the
25 present invention, it is further provided with a second judging device for judging whether or not the current reproduction time point of the main
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picture is beyond the range of reproduction time points in which the sub-picture of the first type is to be displayed, if the sub-picture of the first type is superimposed and displayed on the main picture.
According to this aspect, it is possible to preferably suppress or eliminate such a disadvantage that the sub-picture of the first type is displayed at an unexpected reproduction time point or undesired reproduction time point.
In another aspect of the information reproducing apparatus of the present invention, it is further provided with a fourth controlling device for controlling the storing device to destroy the identification number of the sub-picture of the first type, if the display of the sub-picture of the first type is ended after the sub-picture of the first type is superimposed and displayed on the main picture.
According to this aspect, by the operation of the fourth controlling device, if the display of the sub-picture of the first type is ended, the identification number stored in the storing device is destroyed, as in the case that the current reproduction time point of the main picture is beyond the range of reproduction time points for the sub-picture of the first type. Thus, it is possible to preferably suppress or eliminate such a disadvantage that the sub-picture of the first type is displayed at an unexpected reproduction time point or undesired reproduction time point.
Moreover, it may be also constructed such that the identification number of the sub-picture of the first type is destroyed if the display of the main picture is ended after the sub-picture of the first type is superimposed and displayed on the main picture.
In another aspect of the information reproducing apparatus of the
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present invention, the range of reproduction time points in which the sub-picture of the first type is to be displayed is a range from a reproduction time point at which the display of the sub-picture of the first type is started to a reproduction time point after a lapse of a display period of the sub-picture of 5 the first type.
According to this aspect, it is possible to preferably suppress or eliminate such a disadvantage that the sub-picture of the first type is displayed at an unexpected reproduction time point or undesired reproduction time point.
10 In another aspect of the information reproducing apparatus of the
present invention, the first controlling device controls the storing device to destroy the identification number of the sub-picture of the first type by storing an invalid value into the storing device.
According to this aspect, it is possible to preferably suppress or
15 eliminate such a disadvantage that the sub-picture of the first type is displayed at an unexpected reproduction time point or undesired reproduction time point.
(Embodiment of Information Reproducing Method)
An embodiment of the information reproducing method of the present
20 invention is an information reproducing method in an information reproducing apparatus provided with: a displaying device for displaying a main picture and a sub-picture of a first type, which is superimposed and displayed on the main picture and whose display can be started at a desired reproduction time point on a reproduction time axis of the main picture; and a
25 storing device for storing an identification number of the sub-picture of the first type selected to be superimposed and displayed on the main picture, the
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information reproducing method provided with: a first controlling process of controlling the storing device to destroy the identification number of the sub-picture of the first type, if a current reproduction time point of the main picture is beyond a range of reproduction time points in which the sub-picture 5 of the first type is to be displayed,' and a second controlling process of controlling the storing device to continue to store the identification number of the sub-picture of the first type, if the current reproduction time point of the main picture is not beyond the range of reproduction time points in which the sub-picture of the first type is to be displayed.
10 According to the embodiment of the information reproducing method
of the present invention, it is possible to receive the same benefits as those of the aforementioned information reproducing apparatus of the present invention.
In response to the various aspects of the aforementioned information
15 reproducing apparatus of the present invention, the information reproducing method of the present invention can employ various aspects. (Embodiment of Computer Program)
An embodiment of the computer program of the present invention is a computer program for reproduction control and for controlling a computer
20 provided in the aforementioned information reproducing apparatus of the present invention (including its various aspects), the computer program making the computer function as at least one portion of the first controlling device and the second controlling device.
According to the computer program of the present invention, the
25 aforementioned information reproducing apparatus of the present invention (including its various aspects) can be relatively easily realized as a computer
15

reads and executes the computer program from a program storage device,
such as a ROM, a CD-ROM, a DVD-ROM, and a hard disk, or as it executes
the computer program after downloading the program through a
communication device.
5 Incidentally, in response to the various aspects of the aforementioned
information reproducing apparatus of the present invention, the computer program of the present invention can also employ various aspects.
The above object of the present invention can be also achieved by a computer program product in a computer-readable medium for tangibly
10 embodying a program of instructions executable by a computer provided in the aforementioned information reproducing apparatus of the present invention (including its various aspects), the computer program product making the computer function as at least one portion of the first controlling device and the second controlling device.
15 According to the computer program product of the present invention,
the aforementioned information reproducing apparatus of the present invention can be embodied relatively readily, by loading the computer program product from a recording medium for storing the computer program product, such as a ROM (Read Only Memory), a CD-ROM (Compact Disc -
20 Read Only Memory), a DVD-ROM (DVD Read Only Memory), a hard disk or the like, into the computer, or by downloading the computer program product, which may be a carrier wave, into the computer via a communication device. More specifically, the computer program product may include computer readable codes to cause the computer (or may comprise computer readable
25 instructions for causing the computer) to function as the aforementioned information reproducing apparatus of the present invention.
16

Incidentally, in response to the various aspects of the aforementioned information reproducing apparatus of the present invention, the computer program product of the present invention can also employ various aspects.
These effects and other advantages of the present invention will 5 become more apparent from the example explained below.
As explained above, according to the embodiment of the information
reproducing apparatus of the present invention, it is provided with the
displaying device, the storing device, the first controlling device, and the
second controlling device.
10 According to the embodiment of the information reproducing method
of the present invention, it is provided with the first controlling process and the second controlling process.
According to the embodiment of the computer program of the present invention, it makes a computer function as one portion of the embodiment of 15 the information reproducing apparatus of the present invention.
Therefore, it is possible to preferably display the sub-picture that is superimposed and displayed on the main picture.
Example
20 Hereinafter, the preferred example of the present invention will be
explained with reference to the drawings.
(l) Basic Structure of Information Recording / Reproducing Apparatus
Firstly, with reference to FIG. 1, a description will be given on the
basic structure of an information recording / reproducing apparatus, as an
25 example of the information reproducing apparatus of the present invention.
FIG. 1 is a block diagram conceptually showing the basic structure of an
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information recording / reproducing apparatus 200 in the example.
Incidentally, the information recording / reproducing apparatus 200 has a
function of recording data onto an optical disc 100 and a function of
reproducing the data recorded on the optical disc 100.
5 As shown in FIG- 1, the information recording / reproducing
apparatus 200 is provided with; a disc drive 301 on which the optical disc 100 is actually loaded and on which data recording and data reproduction are performed; and a host computer 302, such as a personal computer, for controlling the data recording and reproduction with respect to the disc drive 10 301.
The disc drive 301 is provided with: the optical disc 100; a spindle motor 351; an optical pickup 352; a signal recording / reproducing device 353; a CPU (drive control device) 354; a memory 355; a data input / output control device 306; and a bus 357, Moreover, the host computer 302 is provided 15 with: a CPU 359; a memory 360,' an operation / display control device 307; an operation button 310; a display panel 311; and a data input / output control device 308.
The spindle motor 351 is intended to rotate and stop the optical disc
100, and operates upon accessing the holographic recording medium 1. More
20 specifically, the spindle motor 351 is adapted to rotate the optical disc 100 at a
predetermined speed and stop it, under spindle servo from a not-illustrated
servo unit or the like.
The optical pickup 352 is provided with e.g. a semiconductor laser
diode, a collimator lens, an objective lens, and the like, in order to perform the
25 recording and the reproduction on the optical disc 100. More specifically, the
optical pickup 352 irradiates the optical disc 100 with a laser beam LB with a
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first power as reading light in the reproduction, and with a second power and with it modulated as writing light in the recording.
The signal recording / reproducing device 353 constitutes one specific example of the "displaying device" of the present invention, and controls the 5 spindle motor 351 and the optical pickup 352, to thereby perform the recording and the reproduction on the optical disc 100. More specifically, the signal recording / reproducing device 353 is provided with e.g. a laser diode . driver (LD driver), a head amplifier, and the like. The laser diode driver generates e.g. a driving pulse and drives the semiconductor laser element
10 disposed in the optical pickup 352. The head ampUfier amplifies an output signal of the optical pickup 352, i.e. reflected light of the laser beam LB, and outputs the amplified signal.
The memory 355 is used in the general data processing and an OPC process on the disc drive 301, including a buffer area for the record /
15 reproduction data, an area used as an intermediate buffer when data is converted into the data that can be used on the signal recording / reproducing device 353, and the like. Moreover, the memory 355 is provided with: a ROM area into which a program for performing an operation as the recorder equipment, i.e. firmware, is stored,' a buffer for temporary storage of the
20 record / reproduction data; a RAM area into which a parameter required for the operation of a firmware program or the like is stored; and the like.
The CPU (drive control device) 354 is connected to the signal recording / reproducing device 353 and the memory 355 through the bus 357, and controls the entire disc drive 301 by giving an instruction to various
25 controlling devices. Typically, software or firmware for operating the CPU 354 is stored in the memory 355.
19

The data input / output control device 306 controls the input / output of the data from the exterior with respect to the disc drive 301, to thereby perform storage to and export from the data buffer on the memory 355. A drive control command issued from the external host computer 302 connected 5 to the disc drive 301 through an interface, such as a SCSI and an ATAPI, is transmitted to the CPU 354 through the data input / output control device 306. Moreover, the data is also exchanged with the host computer 302 through the data input / output control device 306, in the same manner.
The operation / display control device 307 constitutes one specific
10 example of the "inputting device" of the present invention. The operation / display control device 307 receives an operation instruction and performs display with respect to the host computer 302, and transmits an instruction by the operation button 310, such as an instruction to record, to the CPU 359. The CPU 359 may transmit a control command to the information recording /
15 reproducing apparatus 200, through the data input / output control device 308, on the basis of instruction information from the operation / display control device 307, to thereby control the entire disc drive 301. In the same manner, the CPU 359 can transmit a command for requesting the disc drive 301 to transmit an operational state to the host, with respect to the disc drive
20 301. By this, the operational state of the disc drive 301, such as during recording, can be recognized, so that the CPU 359 can output the operational state of the disc drive 301 to the display panel 311, such as a fluorescent tube and an LCD, through the operation / display control device 307.
The memory 360 is an internal memory apparatus used by the host
25 computer 302, and it is provided with: a ROM area in which a firmware program, such as BIOS (Basic Input / Output System), is stored; a RAM area
20

in which variables necessary for the operation of an operating system and an
application program or the like are stored; and the like. Moreover, the
memory 360 may be connected to an external memory apparatus, such as a
not-illustrated hard disk, through the data input / output control device 308.
5 One specific example used by combining the disc drive 301 and the
host computer 302, as explained above, is household equipment, such as recorder equipment for recording and reproducing video images. The recorder equipment records a video signal from a broadcast reception tuner and an external connection terminal, onto a disc. The operation as the
10 recorder equipment is performed by executing a program stored in the memory 360, on the CPU 359. Moreover, in another specific example, the disc drive 301 is a disc drive (hereinafter referred to as a "drive", as occasion demands), and the host computer 302 is a personal computer and a work station. The host computer, such as the personal computer, and the drive
15 are connected through the data input / output control devices 306 and 308, such as the SCSI and the ATAPI, and application, such as writing software, installed in the host computer 302 controls the disc drive 301. (2) Logical Structure of Data recorded on Optical Disc
Next, with reference to FIG. 2 to FIG. 8, a description will be given on
20 the logical structure of the data on the optical disc 100.
Firstly, with reference to FIG. 2 to FIG. 4, a description will be given on the basic structure of the logical structure of the data on the optical disc 100. FIG. 2 is a data structure diagram conceptually showing the logical structure of a title table. FIG. 3 is a data structure diagram conceptually
25 showing the logical structure of a play list. FIG. 4 is a data structure conceptually showing a hierarchy relationship of the logical structure of the
21

data.
As shown in FIG. 2, a title table 10 is recorded on the optical disc 100, wherein the title table 10 indicates objects that constitute a plurality of titles. Here, the title is AV content unit which has a logically large group, such as 5 one movie and one TV program. As described later, the title is an AV content reproduction unit in which a plurality of "play lists" are continuously executed.
On the title table 10, there are recorded pointers 12 which indicate the storage positions of the play lists which constitute each title (for titles #1 10 to #n), in each of the title numbers #1 to #n (wherein n is an integer or 1 or more) for identifying the title. Here, the "play list" is a file in which information necessary for the reproduction of the AV content is stored. As described later, the play list is provided with a plurality of "play items" in each of which information about the reproduction range of the AV content is 15 stored to access the AV content.
Moreover, on the title table 10, there is recorded other information except the aforementioned pointers 12.
Incidentally, FIG. 2 exemplifies the title table 10 in the case where the plurality of titles are recorded on the optical disc 100. If one title is recorded 20 on the optical disc 100, the present invention employs such construction that the pointers 12 to the playlists which constitute the one title are recorded.

Moreover, FIG. 2 exemplifies the title table 10 in which the reproduction unit which is obtained by continuously executing the plurality of play lists, is set as one title,' however, it is obvious that a reproduction unit 25 which is obtained by executing a single play list may be set as one title.
As shown in FIG. 3, the play list (for title #m (wherein l^m^n)) 30,
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whose storage position is indicated by the pointer 12 recorded in the title table 10, includes a plurality of play items 31 and other information 32.
Each of the plurality of play items 31 includes a reproduction start position (in other words, an IN position) of the AV content and a reproduction 5 end position (in other words, an OUT position) of the AV content. Incidentally, the reproduction start position and the reproduction end position are preferably indicated by a time stamp (i.e. a reproduction time length or a reproduction time point) on a reproduction time axis of the AV content.
Moreover, the play list 30 preferably includes the position(s) of one or
10 a plurality of chapters included in the AV content.
As shown in FIG. 4, the data structure explained in FIG. 2 and FIG. 3 has a hierarchic relationship. That is, one title is provided with one or a plurality of play lists 30, and one play list 30 is provided with one or a plurality of play items 31.
15 Then, the play item 31 indicates an access point in a clip by the
reproduction start position and the reproduction end position described above. Incidentally, the "clip" in the example indicates a pair of one AV content stream file (i.e. an actual data file of the AV content, for example, a MPEG 2 transport stream) and clip information, which is information corresponding
20 thereto. Then, the data file of the clip information is referred to as a clip information file.
The reproduction start position and the reproduction end position shown as the time stamp by the play item 31 are converted to address information, at which decoding is to be started in the AV content stream file,
25 by using the clip information file. Thus, the clip information preferably includes a table or the like which indicates a correspondence relationship
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