FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10, rule 13)
“TRANSMISSION APPARATUS, TRANSFER STREAM
TRANSMISSION METHOD AND PROCESSING
APPARATUS”
SONY CORPORATION, of 1-7-1, Konan, Minato-ku, Tokyo
108-0075, Japan
The following specification particularly describes the invention and the manner in
which it is to be performed.
2
DESCRIPTION
TRANSMISSION DEVICE, TRANSMISSION METHOD OF TRANSMISSION
STREAM, AND PROCESSING DEVICE
5 TECHNICAL FIELD
[0001]
The present technology relates to a transmission
device, a transmission method of a transmission stream,
and a processing device, and more particularly to a
10 transmission device and others for transmitting a
transmission stream containing transmission packets
successively disposed in the transmission stream.
BACKGROUND ART
15 [0002]
A capsule layer is provided in some cases as an
interface between a physical layer (Physical layer) for
modulating a transmission line and an IP packet layer for
packetizing data at the time of supply of a service
20 stream on IP packets (for example, see Patent Document 1)
Data free from constraint of time, and file downloading
have been considered as appropriate information contained
in the capsule layer.
25 CITATION LIST
PATENT DOCUMENT
[0003]
Patent Document 1: Japanese Patent Application Laid-Open
No. 2012-015875
30
SUMMARY OF THE INVENTION
3
PROBLEMS TO BE SOLVED BY THE INVENTION
[0004]
In case of a service containing both a service
using broadcasting waves and an IP distribution service,
it is possible that the capsule 5 layer is used for
transmission of a real-time service, such as a case for
transmitting IP packets via broadcasting waves with
broadcasting-wave service packets carried on the IP
packets, in addition to the conventional use of the
10 capsule layer in a file downloading manner. When the
capsule layer has a variable length rather than a fixed
length, a transmission target in an upper layer is
efficiently transmittable. For example, video or audio
is encapsulated in a size of one access unit or larger.
15 [0005]
At the time of a trick play such as fast forward
(Fast Forward) reproduction, or random access, parsing of
variable-length capsules, parsing of multiplexed
transports, and decoding of compressed data are executed
20 before presentation. In this case, parsing of variablelength
packets present in multiple layers needs to be
rapidly completed to shorten a system response time until
presentation of initial video or audio.
[0006]
25 TLV (Type Length Value) is herein discussed as an
example of the capsule layer. In case of TLV, a head of
TLV is detectable as an offset position from a
transmission slot based on a TMCC inserted into a
transmission frame. Subsequently, parsing of IP/UDP and
30 IP/TCP, and parsing of a payload of a transport packet
are executed to finally recognize the presence of a
4
picture (picture) to be initially presented.
[0007]
An object of the present technology is to decrease
a response time until initial presentation in such cases
as reception of a service, and reproduction 5 of reception
data after accumulation of the reception data.
SOLUTIONS TO PROBLEMS
[0008]
10 A concept of the present technology is directed to
a transmission device including:
a transmission unit that transmits a transmission
stream containing transmission packets successively
disposed in the transmission stream; and
15 an information insertion unit that inserts, into
each of the transmission packets, identification
information based on which a packet handled with priority
is identifiable.
[0009]
20 According to the present technology, the
transmission unit transmits a transmission stream
containing transmission packets successively disposed in
the transmission stream. Then, the information insertion
unit inserts, into each of the transmission packets,
25 identification information based on which a packet
handled with priority is identifiable. For example, each
of the transmission packets may be a multilayered packet
containing a multiplexed transport packet in an upper
layer. For example, the information insertion unit may
30 insert the identification information into packets in a
part or all of layers of each of the multilayered packets.
5
[0010]
For example, the information insertion unit may
insert, into packets in a part or all of layers of each
of the multilayered packets, identification information
based on which a transmission packet 5 handled with
priority is identifiable when the corresponding
multiplexed transport packet contains an access unit for
random access. For example, the information insertion
unit may insert, into packets in a part or all of layers
10 of each of the multilayered packets, identification
information based on which a transmission packet handled
with priority is identifiable when the corresponding
multiplexed transport packet contains an access unit
necessary for special reproduction.
15 [0011]
For example, each of the transmission packets may
be a capsule layer packet obtained by encapsulating an IP
packet containing the multiplexed transport packet in a
payload. In this case, each of the transmission packets
20 may be a TLV packet or a GSE packet, for example. For
example, each of the transmission packets may be an IP
packet containing the multiplexed transport packet in a
payload. For example, each of the multiplexed transport
packets may be an MMT packet, an RTP (Real-time Transport
25 Protocol) packet, or a FLUTE (File Delivery over
Unidirectional Transport Protocol) packet.
[0012]
According to the present technology, therefore,
identification information based on which a packet
30 handled with priority is identifiable is inserted into
each of the transmission packets. In this case, a
6
response time until initial presentation decreases in
such cases as reception of a service, and reproduction of
reception data after accumulation of the data.
[0013]
Another concept of the present 5 technology is
directed to a processing device including an acquisition
unit that acquires a transmission stream containing
transmission packets successively disposed in the
transmission stream, wherein
10 identification information based on which a packet
handled with priority is identifiable is inserted into
each of the transmission packets, and
the processing device further includes a processing
unit that processes the acquired transmission stream.
15 [0014]
According to the present technology, the
acquisition unit acquires a transmission stream
containing transmission packets successively disposed in
the transmission stream. The identification information
20 based on which a packet handled with priority is
identifiable is inserted into each of the transmission
packets. The processing unit processes the acquired
transmission stream. For example, each of the
transmission packets may be a multilayered packet
25 containing a multiplexed transport packet in an upper
layer. In this case, the identification information may
be inserted packets in a part or all of layers of each of
the multilayered packets.
[0015]
30 In this case, each of the transmission packets may
be a capsule layer packet, such as a TLV packet or a GSE
7
packet, obtained by encapsulating an IP packet containing
the multiplexed transport packet in a payload, for
example. In this case, each of the transmission packets
may be an IP packet containing the multiplexed transport
packet in a payload, for example. For 5 example, each of
the multiplexed transport packets may be an MMT packet,
an RTP packet, or a FLUTE packet.
[0016]
For example, the acquisition unit may receive the
10 transmission stream via a predetermined transmission line,
and the transmission packet into which the identification
information indicating a packet handled with priority is
inserted may include the multiplexed transport packet
containing an access unit for random access. In this
15 case, the predetermined transmission line may be an RF
transmission line or a communication network transmission
line, for example.
[0017]
For example, the acquisition unit may receive the
20 transmission stream from an accumulation medium or a
server in response to a reproduction command transmitted
to the accumulation medium or the server. In this case,
the transmission packet into which the identification
information indicating a packet handled with priority is
25 inserted may include the multiplexed transport packet
containing an access unit necessary for special
reproduction.
[0018]
According to the present technology, therefore, a
30 transmission stream to be acquired and processed contains
the transmission packets successively disposed in the
8
transmission stream, each of which packets includes
insertion of identification information based on which a
packet handled with priority is identifiable. In this
case, a response time until initial presentation
decreases in such cases as reception 5 of a service, and
reproduction of reception data after accumulation of the
data.
EFFECTS OF THE INVENTION
10 [0019]
According to the present technology, a response
time until initial presentation decreases in such cases
as reception of a service, or reproduction of reception
data after accumulation. Advantageous effects described
15 in this specification are presented only by way of
example, wherefore other advantageous effects or
additional advantageous effects may be offered.
BRIEF DESCRIPTION OF DRAWINGS
20 [0020]
Fig. 1 is a block diagram illustrating a
configuration example of a presentation system according
to an embodiment.
Fig. 2 is a view illustrating transmission protocol
25 stacks.
Fig. 3 is a view illustrating a configuration
example of TMCC information in a transmission frame.
Figs. 4(a) and 4(b) are views illustrating chief
contents of a configuration example of TMCC information
30 in transmission frames.
Fig. 5 is a view illustrating storage of TLV
9
packets in data areas of respective slots in transmission
frames.
Figs. 6(a) and 6(b) are views illustrating an
example where positions of TLV packets are not
synchronized with starts of respective 5 transmission
frames, and an example where positions of TLV packets are
synchronized with starts of respective transmission
frames.
Fig. 7 is a view schematically illustrating a
10 packet configuration of transmission protocol stacks.
Fig. 8 is a view illustrating a configuration of an
MMT packet in a manner of tree structure.
Fig. 9 is a view illustrating types of the MMT
packet.
15 Fig. 10 is a view illustrating a configuration
example of an MMT payload header (mmtp_payload_header()).
Fig. 11 is a view illustrating a configuration
example of an MMT payload header extension in case of
transmission of time information in an MMT payload header
20 (MPU payload header).
Fig. 12 is a view illustrating a configuration
example of a TLV packet (TLV packet()).
Fig. 13 is a view illustrating a more detailed
configuration example of the TLV packet.
25 Fig. 14 is a view illustrating identification
information inserted into a header of a TLV packet, as
information based on which a packet handled with priority
is identifiable.
Fig. 15 is a view illustrating a packet type of a
30 TLV packet.
Fig. 16 is a view illustrating an example of a
10
broadcasting wave transmitting system included in a
broadcasting station.
Fig. 17 is a view illustrating a configuration
example of an IP (Internet Protocol) header.
Fig. 18 is a view illustrating 5 contents of chief
information on a configuration example of an IP header.
Fig. 19 is a view illustrating a configuration
example of “Options” within an IP header.
Fig. 20 is a view illustrating contents of chief
10 information on a configuration example of “Options”
within an IP header.
Fig. 21 is a view illustrating priority packet
identification information defined in “Options” within an
IP header.
15 Fig. 22 is a view illustrating an example of a
broadcasting wave receiving system included in a receiver.
Fig. 23 is a view illustrating a presentation delay
at the time of channel switching (random access).
Fig. 24 is a flowchart schematically illustrating
20 an example of a process executed until decoding and
presentation of a picture at an initial random access
point.
Fig. 25 is a view illustrating a case of
broadcasting channel switching or multicast distribution
25 service switching.
Fig. 26 is a flowchart schematically illustrating
another example of a process executed until decoding and
presentation of a picture at an initial random access
point.
30 Fig. 27 is a view illustrating a case of video ondemand
(VoD) service via a network, or special
11
reproduction of data locally accumulated.
MODES FOR CARRYING OUT THE INVENTION
[0021]
A mode for carrying out the invention 5 (hereinafter
referred to as “embodiment”) is now described. The
description is presented in the following order.
1. Embodiment
2. Modified Example
10 [0022]
<1. Embodiment>
[Configuration Example of Presentation System]
Fig. 1 illustrates a configuration example of a
presentation system 10. According to the presentation
15 system 10, a broadcasting station 110 and a distribution
server 120 are disposed on a transmitting side, while a
receiver 200 is disposed on a receiving side.
[0023]
The broadcasting station 110 transmits a
20 transmission stream carried on broadcasting waves to the
receiving side via an RF transmission line. The
transmission stream is a stream containing TLV (Type
Length Value) packets as transmission packets
successively disposed in the transmission stream. Each
25 of the TLV packets is a multilayered packet containing a
multiplexed transport packet, and media data such as
video and audio data in an upper layer. Each of the TLV
packets is a capsule layer packet obtained by
encapsulating an IP packet containing a multiplexed
30 transport packet in a payload, and a transmission control
signal (TLV-NIT, AMT).
12
[0024]
Fig. 2 illustrates transmission protocol stacks. A
transmission line modulation layer is present in the
lowest part. A transmission slot is present above the
transmission line modulation layer. 5 The transmission
slot contains a TLV packet. An IP packet is present
above the TLV packet. The multiplexed transport packet
containing video, audio, or other media data, and control
data is present above the IP packet via a not-shown UDP
10 packet or TCP packet.
[0025]
One transmission frame is capable of containing
maximum 120 transmission slots in accordance with a
modulation system. TMCC (Transmission and Multiplexing
15 Configuration Control) information is added to each of
the transmission slots. The TMCC information is
constituted by information concerning transmission
control, such as allocation of a transmission stream to
respective transmission slots, and a relationship with a
20 transmission system. An example of the information
contained in the TMCC information is pointer information
indicating positions of TLV packets in transmission slots.
Correct parsing is allowed to start from the beginning of
the TLV packets with reference to the pointer information.
25 [0026]
An area available for transmission of the TMCC
information is 9,422 bits per transmission frame. At the
time of switching of the transmission system or the like,
the TMCC information transmits after-switching
30 information two frames earlier than the actual switching
timing. The minimum update interval for the TMCC
13
information is set to one frame, for example. Fig. 3
illustrates a configuration example (Syntax) of the TMCC
information in a transmission frame.
[0027]
According to an advanced broadband 5 satellite
digital broadcasting system, maximum 16 streams are
transmittable by one satellite repeater. In the
configuration example, “relative stream/slot information”
indicates that any one of relative stream numbers from 0
10 to 15 is allocated to each of slots, and that data on
slots having the same relative stream number constitutes
one stream.
[0028]
In the configuration example, “relative
15 stream/transmission stream ID information” allocates a
transmission stream ID to each of relative streams of the
relative stream numbers 0 through 15. In this case, the
transmission stream ID is set to “TS_ID” when the
relative stream is an MPEG2-TS, and set to “TLV stream
20 ID” when the relative stream is a TLV. As illustrated in
Fig. 4(a), “relative stream/stream type information”
indicates a stream type of each relative stream number.
For example, “0 × 01” indicates an MPEG2-S, while “0 ×
02” indicates a TLV, as illustrated in Fig. 4(b).
25 [0029]
In the configuration example, “pointer/slot
information” is constituted by a top pointer and a last
pointer for each slot, and chiefly used for packet
synchronization and packet invalidation. Fig. 5
30 illustrates an example of storage of TLV packets in data
areas of respective slots. The top pointer indicates an
14
initial packet head byte position in packets stored in
each slot. The last pointer indicates a final packet end
byte position + 1 in packets stored in each slot.
[0030]
The top pointer “0 × FFFF” indicates 5 that a head
byte of an initial TLV packet in a slot is absent. This
pointer indicates a state that the initial TLV packet in
the slot continues from the previous slot. The last
pointer “0 × FFFF” indicates that a final byte of a final
10 TLV packet in a slot is absent. This pointer indicates a
state that the last TLV packet in the slot continues to
the subsequent slot.
[0031]
Fig. 6(a) illustrates an example of a case where a
15 position of a TLV packet is not synchronized with a start
of each transmission frame. A start of each slot is
uniquely determined for the corresponding transmission
frame. A TLV packet is present independently from a slot.
When TLV packets cross over a plurality of transmission
20 frames, there exists a TLV packet to be divided by two
transmission frames.
[0032]
Fig. 6(b) indicates an example of a case where a
position of a TLV packet is synchronized with a start of
25 each transmission frame. A start of each slot is
uniquely determined for the corresponding transmission
frame. A TLV packet is not necessarily synchronized with
a slot, while a start of each transmission frame
corresponds to a start of a TLV packet. More
30 specifically, a start of an initial slot (Slot 1) of each
transmission frame corresponds to a start of a TLV packet.
15
[0033]
In the case illustrated in Fig. 6(b), an invalid
(null) area is often produced in the last part of a
transmission frame, wherefore transmission efficiency
lowers in comparison with the case illustrated 5 in Fig.
6(a). For simplifying the figures, it is assumed that
three slots are present in each transmission frame in the
example illustrated in the figures. Practically, maximum
120 slots are allowed to be contained in accordance with
10 the modulation system, as described above.
[0034]
Fig. 7 schematically illustrates a packet
configuration of transmission protocol stacks. A
transmission slot is constituted by a slot header and
15 transmission slot data. The transmission slot data
contains TLV packets. Each of the TLV packets is
constituted by a header and data. This data contains an
IP packet or a transmission control signal. The
transmission control signal is “TLV-NIT” or “AMT”. In
20 this case, “TLV-NIT” is information for association with
other programs concerning modulation frequency and
broadcasting. On the other hand, “AMT” is an IP address
associated with a broadcasting service.
[0035]
25 An IP packet is constituted by an IP header, and a
UDP packet or a TCP packet as data. The UDP packet
herein is constituted by a UDP header and data, while the
TCP packet is constituted by a TCP header and data. A
multiplexed transport packet is contained as data of the
30 UDP packet or the TCP packet. The multiplexed transport
packet is constituted by a packet header, a payload
16
header, and transport data.
[0036]
The transport data of the multiplexed transport
packet data contains a predetermined number of access
units of an encoded stream of video, 5 audio or other
transmission media. In case of video, 1 access unit
corresponds to 1 picture data. In case of audio, 1
access unit corresponds to an access unit of audio
collectively containing a predetermined number, such as
10 1,024, of samples of data. Intra-coded picture encoded
data corresponding to a random access point is present in
the encoded stream. At the time of random access, this
intra-coded picture encoded data is initially decoded.
[0037]
15 According to this embodiment, it is assumed that
the multiplexed transport packet is a transport packet
having MMT (MPEG Media Transport) structure (see ISO/IEC
CD 23008-1), i.e., an MMT packet. Fig. 8 illustrates a
configuration of an MMT packet in a manner of tree
20 structure.
[0038]
The MMT packet is constituted by an MMT packet
header (MMT Packet Header), an MMT payload header (MMT
Payload Header), and an MMT payload (MMT Payload). The
25 MMT payload contains a message (Message), MPUs (Media
Processing Units), an FEC repair symbol (FEC Repair
Symbol), and others. These are signaled in accordance
with a payload type (payload_type) contained in the MMT
payload header.
30 [0039]
The message herein constitutes information on
17
transmission media. Various types of message contents
are inserted into this message in a manner of table
structure. Each of the MPUs is fragmented into
subdivisions as MFUs (MMT Fragment units) in some cases.
In this case, an MFU header (MFU Header) 5 is added to a
head of each MFU. The MPUs contained in the MMT payload
include an MPU associated with media data such as video,
audio, and subtitles, and further include an MPU
associated with metadata. The MMT packet containing the
10 respective MPUs is identifiable based on a packet ID
(Packet_ID) present in the MMT packet header.
[0040]
Fig. 9 illustrates types of the MMT packet. An
example illustrated in the figure shows classification
15 based on data or information inserted into the payload.
Transport message information is an MMT packet containing
a message (information on transmission media) in the
payload. A transport metadata packet is an MMT packet
containing metadata in the payload. This metadata is
20 data in each box of “styp”, “sidx”, “mmpu”, “moov”, and
“moof” in an MMT file (MP4 file), for example. A
transport media data packet is an MMT packet containing
video, audio, subtitles, and other media data in the
payload.
25 [0041]
The MMT payload header includes flag information
indicating whether or not intra-coded picture encoded
data corresponding to a random access point is present in
the MMT payload. Fig. 10 illustrates a configuration
30 example (Syntax) of an MMT payload header
(mmtp_payload_header()).
18
[0042]
While not described in detail herein, this MMT
payload header contains a payload length (payload_length),
a payload type (payload_type), a fragment type
(fragment_type), a fragment count (5 fragment_count), an
aggregation info flag (aggregation_info_flag), an RAP
flag (random_access_point_flag), a data offset
(data_offset), a data unit number (numDU), a data unit
offset (DU_offset), a payload sequence number
10 (payload_seq_number), a header extension field flag
(header_extension_field_flag), and others.
[0043]
When the header extension field flag is “1”, the
MMT payload header further contains an MMT payload header
15 extension (mmtp_payload_header_extension()). Fig. 11
illustrates a configuration example (Syntax) of the MMT
payload header extension thus contained. This
configuration example corresponds to transmission of time
information (timing information) in the MMT payload
20 header.
[0044]
A 16-bit field of “payload_header_extension_type”
indicates a type of the MMT payload header extension.
For example, “0 × 01” indicates supply of a presentation
25 time stamp (presentation time) in NTP short time format.
In the configuration example, “0 × 02” indicates supply
of the presentation time stamp in NTP short time format,
and a decode time stamp (decode time). In the
configuration example, “0 × 03” indicates supply of a
30 presentation time stamp with 90 KHz accuracy. In the
configuration example, “0 × 04” indicates supply of the
19
presentation time stamp with 90 KHz, and the decode time
stamp.
[0045]
A 16-bit field of “payload_header_extension_length”
indicates a size of the MMT payload header 5 extension. A
32-bit field of “presentation_timestamp” indicates a
value of the presentation time stamp (presentation time).
A 32-bit field of “decoding_timestamp” indicates a value
of the decode time stamp (decode time).
10 [0046]
According to this embodiment, the broadcasting
station 110 inserts, into a TLV packet, identification
information based on which a packet handled with priority
is identifiable. In this view, the broadcasting station
15 110 constitutes an information insertion unit for
inserting identification information. Fig. 12
illustrates a configuration example (Syntax) of a TLV
packet (TLV paket()). This TLV packet is constituted by
a 32-bit TLV header (TLV_header), and a variable-length
20 TLV payload (TLV_payload).
[0047]
Fig. 13 illustrates a more detailed configuration
example (Syntax) of the TLV packet (TLV packet()). A 32-
bit TLV header (TLV_header) is constituted by a 2-bit
25 field of “01”, a 1-bit field of “non_priority_bit1”, a 1-
bit field of “non_priority_bit2”, a 4-bit field of
“reserved_future_use”, an 8-bit field of “packet_type”,
and a 16-bit filed of “length”.
[0048]
30 Flag information indicating whether or not the
corresponding packet is a priority TLV type1 packet is
20
newly defined as the 1-bit field of “non_priority_bit1”.
As illustrated in Fig. 14, “1” indicates that the packet
is a non-priority TLV packet, i.e., that the packet does
not contain data starting an initial byte (1st byte) of
an access unit at a random access point. 5 On the other
hand, “0” indicates that the packet is a priority TLV
type1 packet, i.e., that the packet contains data
starting an initial byte (1st byte) of an access unit at
a random access point.
10 [0049]
Flag information indicating whether or not the
corresponding packet is a priority TLV type2 packet is
newly defined as the 1-bit field of “non_priority_bit2”.
As illustrated in Fig. 14, “1” indicates that the packet
15 is a non-priority TLV packet, i.e., that the packet does
not contain either timing information or a start portion
of attribute information at the time of random access
point presentation. On the other hand, “0” indicates
that the packet is a priority TLV type2 packet, i.e.,
20 that the packet contains timing information, or a start
portion of attribute information at the time of
presentation of a random access point presentation.
[0050]
The TLV packet set to a priority TLV packet is not
25 targeted only at a TLV packet which includes a transport
media packet as an MMT packet containing video, audio, or
other media data. A TLV packet which includes an MMT
packet containing transport message information or a
transport metadata packet is also set to a priority TLV
30 packet as necessary.
[0051]
21
The 8-bit field of “packet_type” indicates a packet
type of the TLV packet (see Fig. 15). In the
configuration example, “0 × 01” indicates that IPv4
packet is contained. In the configuration example, “0 ×
02” indicates that IPv6 packet is 5 contained. In the
configuration example, “0 × 03” indicates that an IP
packet subjected to header compression is contained. In
the configuration example, 0 × FE“ indicates that a
transmission control signal is contained. In the
10 configuration example, ”0 × FF“ indicates that the packet
is a null packet. The 16-bit field of “length” indicates
a size of a variable-length TLV payload (TLV_payload)
continuing from the TLV header (TLV_header).
[0052]
15 Fig. 16 illustrates an example of a broadcasting
wave transmitting system 111 included in the broadcasting
station 110. The transmitting system 111 includes an
encoder unit 112, a multiplexer unit 113, a framing unit
114, and a modulator/emission unit 115. The encoder unit
20 112 encodes video, audio, or other media data to obtain
encoded data. For example, video data is encoded using
MPEG4-AVC, or HEVC (high Efficiency Video Coding), for
example.
[0053]
25 The encoder unit 112 packetizes encoded data such
as video and audio data to generate a multiplexed
transport packet for each medium. As discussed above, it
is assumed that the multiplexed transport packet is an
MMT packet in this embodiment, for example. As discussed
30 above, the MMT packet to be practically transmitted
includes transport message information and a transport
22
metadata packet in the payload, as well as a transport
media packet containing video, audio or other media data
(see Fig. 9).
[0054]
The encoder unit 112 further 5 packetizes a
multiplexed transport packet into an UDP or a TCP, and
adds an IP header to generate an IP packet containing a
multiplexed transport packet. The encoder unit 112
transmits respective IP packets to the multiplexer unit
10 113. The multiplexer unit 113 multiplexes the respective
IP packets.
[0055]
The multiplexer unit 113 further determines whether
or not data of a head byte of an access unit constituting
15 a random access point (intra-coded picture) is contained
based on each IP packet containing video, audio or other
encoded data. Alternatively, when receiving supply of IP
packets containing video, audio or other encoded data
from the encoder unit 112, the multiplexer unit 113
20 simultaneously receives supply of information on an
access unit constituting a random access point (intracoded
picture), as indicated by a broken line in the
figure.
[0056]
25 The multiplexer unit 113 further supplies a
multiplexed stream of IP packets to the framing unit 114.
At this time, the multiplexer unit 113 supplies, to the
framing unit 114, information indicating whether or not
data on a head byte of an access unit constituting a
30 random access point (intra-coded picture) is contained in
accordance with the supply of IP packets containing video,
23
audio, or other encoded data, as indicated by a broken
line in the figure.
[0057]
The framing unit 114 generates a TLV packet as an
encapsulated multiplexed IP packet. The 5 framing unit 114
further generates a TLV packet as an encapsulated
transmission control signal (TLV-NIT, AMT). The framing
unit 114 sets priority packet identification information
contained in a TLV header, i.e., a 1-bit field of
10 “non_priority_bit1” and a 1-bit field of
“non_priority_bit2” at the time of encapsulation (see
Figs. 13 and 14).
[0058]
The framing unit 114 sets the 1-bit field of “non15
priority_bit1” to “0” when a TLV packet contains data
starting an initial byte of an access unit at a random
access point, for indication that the corresponding
packet is a priority TLV type1 packet. The framing unit
114 further sets the 1-bit field of “non-priority_bit2”
20 to “0” when a TLV packet contains timing information or a
start portion of attribute information at the time of
random access point presentation, for indication that the
corresponding packet is a priority TLV type2 packet.
[0059]
25 The framing unit 114 further executes a framing
process for storing respective TLV packets in slots of
transmission frames. The framing unit 114 supplies
generated transmission frames to the modulator/emission
unit 115. The modulator/emission unit 115 executes an RF
30 modulation process for the transmission frames to produce
broadcasting waves, and transmits the produced
24
broadcasting waves to the receiving side through an RF
transmission line.
[0060]
Returning to Fig. 1, the distribution server 120
distributes a transmission stream to 5 the receiving side
via a communication network 300 by multicast distribution.
This transmission stream contains IP packets successively
disposed in the stream, as transmission packets
containing MMT packets similar to the MMT packets handled
10 by the foregoing broadcasting station 110, for example.
Alternatively, the distribution server 120 transmits a
transmission stream to the receiving side via the
communication network 300 as a video on-demand service.
This transmission stream contains predetermined IP
15 packets successively disposed in the stream as
transmission packets including MMT packets, in accordance
with a reproduction mode based on a reproduction command
received from the receiving side. The reproduction mode
includes fast forward (Fast forward) reproduction, fast
20 backward (Fast backward) reproduction, and other special
reproduction as well as an ordinary reproduction mode.
[0061]
According to this embodiment, identification
information based on which a packet handled with priority
25 is identifiable is inserted into each of IP packets as
transmission packets retained in the distribution server
120. Fig. 17 illustrates a configuration example
(Syntax) of an IP (Internet Protocol) header. Fig. 18
illustrates contents of chief information (Semantics) of
30 this configuration example.
[0062]
25
A 4-bit field of “Version” indicates a version of
the IP header. A 4-bit field of “IHL=Hdr Len” indicates
a length of the IP header in units of 32 bits. The
length of the IP header is set to 20 bytes when no option
exists. An 8-bit field of “TOS/DSCP/5 ECN” is a service
type filed. A 16-bit field of “Total Length” indicates a
length of the entire IP packet by a number of bytes.
[0063]
An initial bit in a 3-bit field of “Flags” is
10 unused. The second bit specifies whether to allow
fragmentation. The third bit indicates whether the
corresponding fragment is an intermediate portion of the
original IP packet, or an end of the original IP packet
when the IP packet is fragmented. A 13-bit field of
15 “Fragment Offset” indicates a position of the
corresponding fragment in the order of fragments when the
IP packet is fragmented.
[0064]
An 8-bit filed of “Time To Live” indicates the
20 maximum period for which the IP packet is allowed to
exist on the Internet. This period is specified for the
purpose of preventing permanent continuation of
circulation of an IP packet on the network as a packet
not finding a destination. An 8-bit field of “Protocol”
25 is an identifier for identifying an upper layer protocol.
For example, “1” indicates “ICMP”, “2” indicates “IGMP”,
“3” indicates “TCP”, “17” indicates “UDP”, “41” indicates
“IPv6, and “89” indicates “OSPF”.
[0065]
30 A 16-bit field of “Header Checksum” indicates a CRC
for checking the IP header. A 32-bit field of “Source
26
Address” indicates a transmission source IP address. A
32-bit field of “Destination Address” indicates a
destination IP service.
[0066]
Fig. 19 illustrates a configuration 5 example
(Syntax) of “Options”. Fig. 20 illustrates contents of
chief information on this configuration example
(Semantics). A 1-bit field of “type_copy” indicates a
subject to be copied within an initial fragment at the
10 time of “1”, and indicates a subject to be copied in all
fragments at the time of “0”. In addition, “type_class”
indicates a type of a target for application. A 5-bit
field of “type_number” indicates a type number. For
example, “01111” is newly defined as a type number
15 indicating media access priority information (Media
Access Priority Information). An 8-bit field of “length”
indicates a size of the subsequent part by a number of
bytes.
[0067]
20 For example, information or the like for
identifying inclusion of an initial byte of an access
unit at a random access point is defined by “type_number
= ‘01111’” and “length = 2” as illustrated in Fig. 21.
In a 2-byte “information” in this case, “0 × 0001”
25 indicates inclusion of an initial byte (1st byte) of an
access unit at a random access point, timing information,
or a start portion of attribute information at the time
of random access point presentation. On the other hand,
“0 × 0000” indicates inclusion of other information.
30 [0068]
Allocation of values is not limited to the
27
allocation in this example, but may be allocation in
other manners. For example, while “0 × 0001” indicates
inclusion of an initial byte (1st byte) of an access unit
at a random access point, the timing information, or a
start portion of attribute information 5 at the time of
random access point presentation in the foregoing example,
the presence of these may be individually indicated by
respective values.
[0069]
10 Returning to Fig. 1, the receiver 200 includes a
tuner 201, a demultiplexer 202, a decoder 203, a display
204, and a gateway/network router 205. The tuner 201 and
the gateway/network router 205 constitute an acquisition
unit. The tuner 201 receives broadcasting waves
15 transmitted from the transmitting side via an RF
transmission line, executes RF demodulation to obtain
transmission frames, further executes a deframing process
and decapsulating process, and outputs IP packets. The
tuner 201 supplies transmission control signals (TLV-NIT,
20 AMT) obtained by decapsulation of TLV packets to a notshown
control unit.
[0070]
An accumulation medium 210 disposed outside the
receiver 200, such as an HDD, is connected with the tuner
25 201 to allow recording reproduction of a transmission
stream obtained by the tuner 201. At the time of
reproduction, the tuner 201 transmits a reproduction
command to the accumulation medium 210 to receive the
reproduced transmission stream from the accumulation
30 medium 210. Then, the tuner 201 executes decapsulation
of the received transmission stream, and outputs IP
28
packets. In this case, special reproduction such as fast
forward reproduction and fast backward reproduction may
be performed as well as ordinary reproduction in
accordance with the reproduction mode indicated by the
reproduction 5 command.
[0071]
The tuner 201 supplies output IP packets to the
demultiplexer 202. At this time, the tuner 201 supplies
priority packet identification information extracted from
10 headers of TLV packets to the demultiplexer 202 in
accordance with the supply of the respective IP packets.
The demultiplexer 202 executes a process for extracting
data for each type of the data (video, audio, metadata,
message and the like) contained in the payload from the
15 IP packets received from the tuner 201. The
demultiplexer 202 supplies the IP packets extracted for
each type to the corresponding decoder 203 together with
the priority packet identification information.
[0072]
20 The decoder 203 executes a depacketizing process,
and further a decoding process as necessary, for the IP
packets for each type. The decoder 203 supplies a
message or metadata to the not-shown control unit. The
decoder 203 supplies video data to the display 204
25 corresponding to a display unit, and audio data to a notshown
audio output unit, such as a speaker.
[0073]
Fig. 22 illustrates an example of a broadcasting
wave receiving system 211 included in the receiver 200.
30 The receiving system 211 includes a tuner/demodulator
unit 212, a deframing unit 213, a demultiplexer unit 214,
29
and a decoder unit 215. The tuner/demodulator unit 212
receives broadcasting waves through an RF transmission
line, and executes an RF demodulating process to obtain
transmission frames containing TLV packets in
transmission slots. The tuner/demodulator 5 unit 212
supplies these transmission frames to the deframing unit
213.
[0074]
The deframing unit 213 extracts TLV packets
10 contained in respective slots from transmission frames.
The deframing unit 213 further executes a decapsulating
process for the extracted respective TLV packets to
obtain IP packets or transmission control signals (TLVNIT,
AMT).
15 [0075]
The deframing unit 213 supplies the obtained
transmission control signals to the not-shown control
unit. The deframing unit 213 further supplies the
obtained IP packets to the demultiplexer 214. At this
20 time, the deframing unit 213 also supplies priority
packet identification information contained in TLV
headers to the demultiplexer unit 214 in accordance with
the supply of the respective IP packets, as illustrated
in a broken line in the figure. As discussed above, this
25 priority packet identification information is constituted
by the 1-bit filed of “non_priority_bit1”, and the 1-bit
field of “non_priority_bit2” (see Fig. 13).
[0076]
The demultiplexer unit 214 executes a process for
30 extracting data for each type of data contained in the
payload from the IP packets received from the deframing
30
unit 213. The demultiplexer unit 214 supplies the IP
packets extracted for each type to the corresponding
decoder unit 215. At this time, the demultiplexer unit
214 also supplies the priority packet identification
information to the decoder unit 215 5 as indicated by a
broken line in accordance with the supply of the
respective IP packets.
[0077]
The decoder unit 215 executes a depacketizing
10 process, and further a decoding process as necessary, for
the IP packets for each type. The decoder unit 215
supplies a message or metadata to the not-shown control
unit. The decoder unit 215 supplies video data to a notshown
display unit, and audio data to a not-shown audio
15 output unit.
[0078]
Returning to Fig. 1, the gateway/network router
unit 205 receives a transmission stream of a service
distributed from the distribution server 120 via the
20 communication network 300 by multicast distribution, and
outputs IP packets similar to the output from the
foregoing tuner 201. Each header of the IP packets
contains priority packet identification information.
This priority packet identification information is
25 information on the header option “type=01111”, and
“information” as discussed above (see Figs. 19 through
21).
[0079]
An accumulation medium 220 disposed outside the
30 receiver 200, such as an HDD, is connected with the
gateway/network router unit 205 via a local network to
31
allow recording reproduction of a transmission stream
received by the gateway/network router unit 205. At the
time of reproduction, the gateway/network router unit 205
transmits a reproduction command to the accumulation
medium 220 to receive a reproduced transmission 5 stream
from the accumulation medium 220, and outputs IP packets
constituting the transmission frame. In this case,
special reproduction such as fast forward reproduction
and fast backward reproduction may be executed as well as
10 normal reproduction in accordance with the reproduction
mode indicated by the reproduction command.
[0080]
Alternatively, the gateway/network router unit 205
transmits a reproduction command to the distribution
15 server 120 to receive a transmission stream of a video
on-demand service from the distribution server 120 via
the communication network 300, and outputs IP packets
similar to the IP packets output by the foregoing
multicast distribution. In this case, the mode of the
20 transmission stream transmitted from the distribution
server 120 corresponds to the reproduction mode indicated
by the reproduction command. The reproduction mode
includes fast forward reproduction, fast backward
reproduction, or other special reproduction as well as
25 the normal reproduction mode.
[0081]
The gateway/network router unit 205 supplies output
IP packets to the demultiplexer 202. The demultiplexer
202 executes a process for extracting data for each type
30 (such as video, audio, metadata, and messages) contained
in the payload from the IP packets received from the
32
gateway/network router unit 205. The demultiplexer 202
supplies the IP packets extracted for each type to the
corresponding decoder 203.
[0082]
The decoder 203 executes a depacketizing 5 process,
and further a decoding process as necessary, for the IP
packets for each type. The decoder 203 supplies a
message or metadata to the not-shown control unit. The
decoder 203 supplies video data to the display 204
10 corresponding to a display unit, and audio data to a notshown
audio output unit, such as a speaker.
[0083]
Operation of the presentation system 10 illustrated
in Fig. 1 is hereinafter described. Initially discussed
15 is a process executed for broadcasting waves received by
the tuner 201 of the receiver 200 from the broadcasting
station 110. In this case, the broadcasting station 110
transmits broadcasting waves to the receiving side via an
RF transmission line. The broadcasting waves carry a
20 transmission stream which includes TLV packets as
transmission packets successively disposed in the stream.
The tuner 201 of the receiver 200 receives these
broadcasting waves.
[0084]
25 The tuner 201 executes an RF demodulation process
for the received broadcasting waves to obtain
transmission frames, and further executes a deframing
process and decapsulation to output IP packets. In this
case, transmission control signals (TLV-NIT, AMT)
30 obtained by decapsulation of TLV packets are supplied to
the not-shown control unit.
33
[0085]
The IP packets output from the tuner 201 are
supplied to the demultiplexer 202. At this time,
priority packet identification information extracted from
headers of the TLV packets is also 5 supplied from the
tuner 201 to the demultiplexer 202 in accordance with the
supply of the respective IP packets. The demultiplexer
202 executes a process for extracting data for each type
(such as video, audio, metadata, and messages) contained
10 in the payload from the IP packets sequentially supplied
from the tuner 201.
[0086]
The IP packets for each type extracted by the
demultiplexer 202 are supplied to the corresponding
15 decoder 203 together with the priority packet
identification information. The decoder 203 executes a
depacketizing process, and further executes a decoding
process as necessary, for the IP packets for each type.
Video data obtained by the decoder 203 is supplied to the
20 display 204 corresponding to a display unit to
presentation an image. On the other hand, audio data
video data obtained by the decoder 203 is supplied to a
not-shown audio output unit, such as a speaker, to output
voices. Messages and metadata obtained by the decoder
25 203 are supplied to the not-shown control unit.
[0087]
Described hereinafter is operation executed at the
time of broadcasting channel switching (random access)
caused in response to operation by a user. In this case,
30 a target of a presentation process executed by the
receiver 200 starts from an initial random access point
34
(RAP) of a transmission stream after the channel
switching. This random access point is targeted at a
head of an access unit constituted only by non-predictive
components (I picture, IDR picture), or a start point of
message information associated with 5 this access unit.
[0088]
Fig. 23 illustrates an example of switching from a
channel A (CH-A) to a channel B (CH-B) at a service
switching point SSP. In this case, at least a delay t1
10 is produced from SSP to RAP until presentation is
restarted. In addition, when a prediction difference
picture (P picture, B picture) referring to a picture
disposed before I picture in the order of presentation is
present after RAP, a delay t2 is also produced due to the
15 presence of the prediction difference picture.
[0089]
According to this embodiment, a process for parsing
a header of each packet in a transmission stream until an
initial random access point (RAP) is appropriately
20 omissible based on the priority packet identification
information contained in headers of TLV packets. In this
case, a delay until decoding and presentation of a
picture at an initial random access point decreases,
wherefore a response time until initial presentation
25 decreases.
[0090]
A flowchart illustrated in Fig. 24 schematically
shows a process executed until decoding and presentation
of a picture at an initial random access point. In step
30 ST1, the receiver 200 starts the process at a service
switching point (random access position). Then, the
35
receiver 200 executes a demodulating process in step ST2,
and executes deframing to extract a TLV packet from a
transmission frame in step ST3.
[0091]
In step ST4, the receiver 200 5 parses a header of
the TLV packet. In step ST5, the receiver 200 determines
whether or not priority identification information
contained in the header indicates a priority packet.
More specifically, the receiver 200 determines whether or
10 not “Non_priority_bit1 = 0” is indicated. When the
receiver 200 determines that the information indicates a
priority packet, the process proceeds to step ST6.
[0092]
In step ST6, the receiver 200 parses an IP header.
15 In step ST7, the receiver 200 parses a header of UDP or
TCP. In step ST8, the receiver 200 parses an MMT payload
header. In step ST9, the receiver 200 determines whether
or not “random_access_point_flag” indicates RAP. When
determining that RAP is indicated, the receiver 200
20 starts decoding in step ST10, starts presentation in step
ST11, and ends the process in step ST12.
[0093]
Solid arrows in Fig. 25 indicate search routes for
finding a random access point in an encoded stream based
25 on the foregoing flowchart illustrated in Fig. 24. In
this case, hierarchical packet parsing from the random
access position (service switching time) to the random
access point (RAP) is unnecessary, but only checking of a
header in the TLV packet on the lowermost layer is
30 required. Accordingly, a delay T1 until decoding and
presentation of a picture at an initial random access
36
point becomes the minimum after random access.
[0094]
The foregoing example is a case of an IP packet
contained in a TLV packet and not including insertion of
identification information based 5 on which a packet
handled with priority is identifiable. However, it is
possible that this IP packet contained in the TLV packet
includes identification information similar to the
identification information of an IP packet corresponding
10 to a transmission packet retained in the distribution
server 120 (see Figs. 19 through 21).
[0095]
A flowchart illustrated in Fig. 26 schematically
shows a process executed in this case until decoding and
15 presentation of a picture at an initial random access
point. In step ST11, the receiver 200 starts the process
at a service switching point (random access position).
In step ST12, the receiver 200 executes a demodulating
process, and executes deframing in step ST13 to extract a
20 TLV packet from a transmission frame.
[0096]
In step ST14, the receiver 200 parses a header of
the TLV packet. In step ST15, the receiver 200
determines whether or not priority packet identification
25 information contained in the header indicates a priority
packet. For example, the receiver 200 determines whether
or not “Non_priority_bit1 = 0” is indicated. When the
receiver 200 determines that a priority packet is
indicated, the process proceeds to step ST16.
30 [0097]
In step ST16, the receiver 200 parses an IP header.
37
In step ST17, the receiver 200 determines whether or not
the priority packet identification information contained
in the header indicates a priority packet. For example,
the receiver 200 determines whether or not “type=01111”
is indicated, and whether or not the 16-5 bit “information”
is “0 × 0001”. When the receiver 200 determines that a
priority packet is indicated, the process proceeds to a
step in ST18.
[0098]
10 In step ST18, the receiver 200 parses a header of
UDP or TCP. In step ST19, the receiver 200 parses an MMT
payload header. In step ST20, the receiver 200
determines whether or not “random_access_point_flag” is
RAP. When RAP is indicated, the receiver 200 starts
15 decoding in step ST21, starts presentation in step ST22,
and ends the process in step ST23.
[0099]
Broken arrows in Fig. 25 indicate search routes for
finding a random access point in an encoded stream based
20 on the foregoing flowchart illustrated in Fig. 26.
Similarly to the above case, hierarchical packet parsing
from the random access position (service switching point)
to the random access point is unnecessary, but only
checking of a header of a TLV packet on the lowest layer
25 is required. Accordingly, the delay T1 until decoding
and presentation of a picture at the initial random
access point becomes the minimum.
[0100]
Described next is operation executed at the time of
30 special reproduction, such as fast forward reproduction,
based on a reproduction command transmitted to the
38
accumulation medium 210 in response to operation by the
user. In this case, TLV packets containing access units
at random access points (RAPs) are selectively extracted
from the accumulation medium 210, for example. Then, a
transmission stream containing these 5 TLV packets is
returned to the tuner 201 as a reproduction transmission
stream.
[0101]
The tuner 201 decapsulates the TLV packets
10 contained in the transmission stream supplied from the
accumulation medium 210, and outputs IP packets. In this
case, transmission control signals (TLV-NIT, AMT)
obtained by decapsulation of TLV packets are supplied to
the not-shown control unit.
15 [0102]
The IP packets output from the tuner 201 are
supplied to the demultiplexer 202. The demultiplexer 202
executes a process for extracting data for each type of
data (video and audio) contained in the payload from the
20 IP packets sequentially supplied from the tuner 201. The
IP packets for each type extracted by the demultiplexer
202 are supplied to the corresponding decoder 203
together with the priority packet identification
information.
25 [0103]
The decoder 203 executes a depacketizing process,
and further a decoding process for the IP packets for
each type. Video data obtained by the decoder 203 is
supplied to the display 204 corresponding to the display
30 unit, where an image of special reproduction, such as
fast forward reproduction is displayed. On the other
39
hand, audio data obtained by the decoder 203 is supplied
to the not-shown audio output unit, such as a speaker,
where a voice corresponding to the display image is
output.
5 [0104]
At the time of selective extraction of TLV packets
containing access units at random access points (RAPs)
from the accumulation medium 210, a process for parsing
headers of respective packets in the transmission stream
10 between respective random access points (RAPs) is
appropriately omissible based on priority packet
identification information contained in the headers of
the TLV packets. Accordingly, a load and required time
for selective extraction of the TLV packets containing
15 access units at random access points (RAPs) decrease.
[0105]
While not explained in detail herein, a process for
finding TLV packets containing random access points
(RAPs) in the accumulation medium 210 is executed in a
20 manner similar to the process for finding TLV packets
containing access units at random access points (RAPs)
executed at the time of the foregoing random access (see
Fig. 24).
[0106]
25 Solid arrows in Fig. 27 indicate search routes for
finding random access points in an encoded stream when
packet identification information is inserted only in
headers of TLV packets in the accumulation medium 210 as
described above. In this case, hierarchical packet
30 parsing in an interval T2 between random access points is
unnecessary, wherefore a processing load produced in the
40
accumulation medium 210 decreases. Accordingly, a
reproduction speed at the time of fast forward
reproduction increases, for example. Broken arrows in
Fig. 27 indicate search paths for finding random access
points in an encoded stream when packet 5 identification
information is inserted into headers of IP packets as
well as headers of TLV packets.
[0107]
Discussed next is a process executed for a
10 transmission stream of a service transmitted from the
distribution server 120 via the communication network 300
and received by the gateway/network router 205 of the
receiver 200. In this case, IP packets contained in the
received transmission stream are output from the
15 gateway/network router 205. Each header of the IP
packets contains priority packet identification
information.
[0108]
The IP packets output from the gateway/network
20 router 205 are supplied to the demultiplexer 202. The
demultiplexer 202 executes a process for extracting data
for each type (such as video, audio, metadata, and
messages) contained in the payload from the IP packets
sequentially supplied from the tuner 201.
25 [0109]
The IP packets for each type extracted by the
demultiplexer 202 are supplied to the corresponding
decoder 203 together with the priority packet
identification information. The decoder 203 executes a
30 depacketizing process, and further executes a decoding
process as necessary, for the IP packets for each type.
41
Video data obtained by the decoder 203 is supplied to the
display 204 corresponding to a display unit to
presentation an image. On the other hand, audio data
video data obtained by the decoder 203 is supplied to a
not-shown audio output unit, such as a 5 speaker, to output
voices. Messages and metadata obtained by the decoder
203 are supplied to the not-shown control unit.
[0110]
Described herein is operation executed at the time
10 of service switching of multicast distribution (random
access) caused in response to operation by the user. In
this case, a target of a presentation process executed by
the receiver 200 starts from an initial random access
point (RAP) of the transmission stream after service
15 switching. This random access point is targeted at a
head of an access unit constituted only by non-predictive
components (I picture, IDR picture), or a start point of
message information associated with this access unit.
[0111]
20 While not described in detail herein, a process for
parsing headers of respective packets in the transmission
stream until the initial random access point (RAP) is
appropriately omissible based on priority packet
identification information contained in the headers of
25 the IP packets similarly to the foregoing case of
broadcasting channel switching (see Fig. 25).
Accordingly, a delay until decoding and presentation of a
picture at the initial random access point decreases,
wherefore a response time until initial presentation
30 decreases.
[0112]
42
Described next is operation executed at the time of
special reproduction, such as fast forward reproduction,
based on a reproduction command transmitted to the
accumulation medium 220 in response to operation by the
user. In this case, IP packets containing 5 access units
at random access points (RAPs) are selectively extracted
from the accumulation medium 220. Then, a transmission
stream containing these IP packets is returned to the
gateway/network router 205 as a reproduction transmission
10 stream.
[0113]
The gateway/network router 205 outputs the IP
packets contained in the transmission stream supplied
from the accumulation medium 220. The demultiplexer 202
15 executes a process for extracting data for each type
(video and audio) contained in the payload from the IP
packets sequentially supplied from the gateway/network
router 205. The IP packets extracted by the
demultiplexer 202 for each type are supplied to the
20 corresponding decoder 203.
[0114]
The decoder 203 executes a depacketizing process,
and further a decoding process for the IP packets for
each type. Video data obtained by the decoder 203 is
25 supplied to the display 204 corresponding to the display
unit, where an image of special reproduction, such as
fast forward reproduction is displayed. On the other
hand, audio data obtained by the decoder 203 is supplied
to the not-shown audio output unit, such as a speaker,
30 where a voice corresponding to the display image is
output.
43
[0115]
At the time of selective extraction of IP packets
containing access units at random access points (RAPs)
from the accumulation medium 220, a process for parsing
headers of respective packets in the transmission 5 stream
between respective random access points (RAPs) is
appropriately omissible based on priority packet
identification information contained in headers of the IP
packets. Accordingly, a load and required time for
10 selective extraction of IP packets containing access
units at random access points (RAPs) decrease.
[0116]
Described next is operation executed for special
reproduction, such as fast forward reproduction, at the
15 time of reception of a transmission stream based on a
reproduction command transmitted to the distribution
server 120 in response to operation by the user. In this
case, the distribution server 120 selectively extracts IP
packets containing access units at random access points
20 (RAPs), for example, based on priority packet
identification information contained in headers of IP
packets, and returns a transmission stream containing
these IP packets to the gateway/network router 205.
[0117]
25 The gateway/network router 205 outputs the IP
packets contained in the transmission stream supplied
from the distribution server 120. The demultiplexer 202
executes a process for extracting data for each type
(video and audio) contained in the payload from the IP
30 packets sequentially supplied from the gateway/network
router 205. The IP packets for each type extracted by
44
the demultiplexer 202 are supplied to the corresponding
decoder 203 together with the priority packet
identification information.
[0118]
The decoder 203 executes a depacketizing 5 process,
and further a decoding process for the IP packets for
each type. Video data obtained by the decoder 203 is
supplied to the display 204 corresponding to the display
unit, where an image of special reproduction, such as
10 fast forward reproduction is displayed. On the other
hand, audio data obtained by the decoder 203 is supplied
to the not-shown audio output unit, such as a speaker,
where a voice corresponding to the display image is
output.
15 [0119]
According to the presentation system 10 illustrated
in Fig. 1 and described above, identification information
for determining whether or not a transmission packet (TLV
packet or TP packet) contained in a transmission stream
20 transmitted from the transmitting side is a packet to be
handled with priority is inserted into the corresponding
packet. Accordingly, a response time until initial
presentation on the receiving side is allowed to decrease
in such cases as reception of a service, and reproduction
25 after accumulation of reception data.
[0120]
For example, a delay until decoding and
presentation of a picture at an initial random access
point becomes the minimum after random access when this
30 identification information is used at the time of
broadcasting channel switching or multicast distribution
45
service switching. Moreover, a processing load and
required time for special reproduction, such as fast
forward reproduction, decrease by the use of this
identification information at the time of special
reproduction of data locally 5 accumulated.
[0121]
<2. Modified Example>
According to the embodiment described above, TLV
packets are used as capsule layer packets for
10 broadcasting by way of example. However, capsule layer
packets are not limited to TLV packets, but may be GSE
(Generic Stream Encapsulation) packets, or other packets
having a function similar to the function of these
packets. Similarly, multiplexed transport packets are
15 not limited to MMT packets. For example, RTP (Real-time
Transport Protocol) packets, or FLUTE (File Delivery over
Unidirectional Transport protocol) packets may be used.
[0122]
According to the embodiment described above, the
20 receiver 200 includes an output unit, i.e., a display, a
speaker or other output units. However, the output
portion and the like of the receiver 200 may be
separately provided. In this case, the receiver becomes
a device having a configuration of a set top box.
25 [0123]
The present technology may have the following
configurations.
(1) A transmission device including:
a transmission unit that transmits a transmission
30 stream containing transmission packets successively
disposed in the transmission stream; and
46
an information insertion unit that inserts, into
each of the transmission packets, identification
information based on which a packet handled with priority
is identifiable.
(2) The transmission device according 5 to (1) noted
above, wherein each of the transmission packets is a
multilayered packet containing a multiplexed transport
packet in an upper layer.
(3) The transmission device according to (2) noted
10 above, wherein the information insertion unit inserts the
identification information into packets in a part or all
of layers of each of the multilayered packets.
(4) The transmission device according to (3) noted
above, wherein the information insertion unit inserts,
15 into packets in a part or all of layers of each of the
multilayered packets, identification information based on
which a transmission packet handled with priority is
identifiable when the corresponding multiplexed transport
packet contains an access unit for random access.
20 (5) The transmission device according to (3) noted
above, wherein the information insertion unit inserts,
into packets in a part or all of layers of each of the
multilayered packets, identification information based on
which a transmission packet handled with priority is
25 identifiable when the corresponding multiplexed transport
packet contains an access unit necessary for special
reproduction.
(6) The transmission device according to any one of
(2) through (5) noted above, wherein each of the
30 transmission packets is a capsule layer packet obtained
by encapsulating an IP packet containing the multiplexed
47
transport packet in a payload.
(7) The transmission device according to (6) noted
above, wherein each of the transmission packets is a TLV
packet or a GSE packet.
(8) The transmission device 5 according to (2)
through (5) noted above, wherein each of the transmission
packets is an IP packet containing the multiplexed
transport packet in a payload.
(9) The transmission device according to any one of
10 (2) through (8) noted above, wherein each of the
multiplexed transport packets is an MMT packet, an RTP
packet, or a FLUTE packet.
(10) A transmission method of a transmission stream
including:
15 transmitting a transmission stream containing
transmission packets successively disposed in the
transmission stream; and
inserting, into each of the transmission
packets, identification information based on which a
20 packet handled with priority is identifiable.
(11) A processing device including an acquisition
unit that acquires a transmission stream containing
transmission packets successively disposed in the
transmission stream, wherein
25 identification information based on which a packet
handled with priority is identifiable is inserted into
each of the transmission packets, and
the processing device further includes a processing
unit that processes the acquired transmission stream.
30 (12) The processing device according to (11) noted
above, wherein
48
each of the transmission packets is a multilayered
packet containing a multiplexed transport packet in an
upper layer, and
the identification information is inserted into
packets in a part or all of layers 5 of each of the
multilayered packets.
(13) The processing device according to (12) noted
above, wherein each of the transmission packets is a
capsule layer packet obtained by encapsulating an IP
10 packet containing the multiplexed transport packet in a
payload.
(14) The processing device according to (13) noted
above, wherein each of the transmission packets is a TLV
packet or a GSE packet.
15 (15) The processing device according to (12) noted
above, wherein each of the transmission packets is an IP
packet containing the multiplexed transport packet in a
payload.
(16) The processing device according to any one of
20 (12) through (15) noted above, wherein each of the
multiplexed transport packets is an MMT packet, an RTP
packet, or a FLUTE packet.
(17) The processing device according to any one of
(12) through (15) noted above, wherein
25 the acquisition unit receives the transmission
stream via a predetermined transmission line, and
the transmission packet into which the
identification information indicating a packet handled
with priority is inserted includes the multiplexed
30 transport packet containing an access unit for random
access.
49
(18) The processing device according to (17) noted
above, wherein the predetermined transmission line is an
RF transmission line or a communication network
transmission line.
(19) The processing device according 5 to any one of
(12) through (15) noted above, wherein
the acquisition unit receives the transmission
stream from an accumulation medium or a server in
response to a reproduction command transmitted to the
10 accumulation medium or the server, and
the transmission packet into which the
identification information indicating a packet handled
with priority is inserted includes the multiplexed
transport packet containing an access unit necessary for
15 special reproduction.
[0124]
The present technology is chiefly characterized in
that a response speed until initial presentation
decreases at the time of random access, for example, by
20 inserting identification information, based on which
information a packet handled with priority is
identifiable, into a capsule layer packet (transmission
packet) obtained by encapsulating an IP packet containing
a multiplexed transport packet in a payload (see Figs. 1
25 and 13).
REFERENCE SIGNS LIST
[0125]
10 Presentation system
30 110 Broadcasting station
111 Transmitting system
50
112 Encoder unit
113 Multiplexer unit
114 Framing unit
115 Modulator/emission unit
120 Distribution 5 server
200 Receiver
201 Tuner
202 Demultiplexer
203 Decoder
10 204 Display
205 Gateway/network router
210 Accumulation medium
211 Receiving system
212 Tuner/demodulator unit
15 213 Deframing unit
214 Demultiplexer unit
215 Decoder unit
220 Accumulation medium
51
CLAIMS
1. A transmission device comprising:
a transmission unit that transmits a transmission
stream containing transmission packets 5 successively
disposed in the transmission stream; and
an information insertion unit that inserts, into
each of the transmission packets, identification
information based on which a packet handled with priority
10 is identifiable.
2. The transmission device according to claim 1,
wherein each of the transmission packets is a
multilayered packet containing a multiplexed transport
15 packet in an upper layer.
3. The transmission device according to claim 2,
wherein the information insertion unit inserts the
identification information into packets in a part or all
20 of layers of each of the multilayered packets.
4. The transmission device according to claim 3,
wherein the information insertion unit inserts, into
packets in a part or all of layers of each of the
25 multilayered packets, identification information based on
which a transmission packet handled with priority is
identifiable when the corresponding multiplexed transport
packet contains an access unit for random access.
30 5. The transmission device according to claim 3,
wherein the information insertion unit inserts, into
52
packets in a part or all of layers of each of the
multilayered packets, identification information based on
which a transmission packet handled with priority is
identifiable when the corresponding multiplexed transport
packet contains an access unit necessary 5 for special
reproduction.
6. The transmission device according to claim 2,
wherein each of the transmission packets is a capsule
10 layer packet obtained by encapsulating an IP packet
containing the multiplexed transport packet in a payload.
7. The transmission device according to claim 6,
wherein each of the transmission packets is a TLV packet
15 or a GSE packet.
8. The transmission device according to claim 2,
wherein each of the transmission packets is an IP packet
containing the multiplexed transport packet in a payload.
20
9. The transmission device according to claim 2,
wherein each of the multiplexed transport packets is an
MMT packet, an RTP packet, or a FLUTE packet.
25 10. A transmission method of a transmission stream
comprising:
transmitting a transmission stream containing
transmission packets successively disposed in the
transmission stream; and
30 inserting, into each of the transmission
packets, identification information based on which a
53
packet handled with priority is identifiable.
11. A processing device comprising an acquisition unit
that acquires a transmission stream containing
transmission packets successively 5 disposed in the
transmission stream, wherein
identification information based on which a packet
handled with priority is identifiable is inserted into
each of the transmission packets, and
10 the processing device further includes a processing
unit that processes the acquired transmission stream.
12. The processing device according to claim 11,
wherein
15 each of the transmission packets is a multilayered
packet containing a multiplexed transport packet in an
upper layer, and
the identification information is inserted into
packets in a part or all of layers of each of the
20 multilayered packets.
13. The processing device according to claim 12,
wherein each of the transmission packets is a capsule
layer packet obtained by encapsulating an IP packet
25 containing the multiplexed transport packet in a payload.
14. The processing device according to claim 13,
wherein each of the transmission packets is a TLV packet
or a GSE packet.
30
15. The processing device according to claim 12,
54
wherein each of the transmission packets is an IP packet
containing the multiplexed transport packet in a payload.
16. The processing device according to claim 12,
wherein each of the multiplexed transport 5 packets is an
MMT packet, an RTP packet, or a FLUTE packet.
17. The processing device according to claim 12,
wherein
10 the acquisition unit receives the transmission
stream via a predetermined transmission line, and
the transmission packet into which the
identification information indicating a packet handled
with priority is inserted includes the multiplexed
15 transport packet containing an access unit for random
access.
18. The processing device according to claim 17,
wherein the predetermined transmission line is an RF
20 transmission line or a communication network transmission
line.
19. The processing device according to claim 12,
wherein
25 the acquisition unit receives the transmission
stream from an accumulation medium or a server in
response to a reproduction command transmitted to the
accumulation medium or the server, and
the transmission packet into which the
30 identification information indicating a packet handled
with priority is inserted includes the multiplexed
55
transport packet containing an access unit necessary for
special reproduction.
56
ABSTRACT
“TRANSMISSION APPARATUS, TRANSFER STREAM TRANSMISSION
METHOD AND PROCESSING APPARATUS”
The objective of the invention is to shorten a response time until an initial display in a
case of receiving a service, a case of reproducing received data after storing the
received data, or the like. When a transfer stream, in which transfer packets are
consecutively arranged, is transmitted, determination information for determining
whether a transfer packet is to be treated on a priority basis is inserted into the packet.
For example, the transfer packets are of a multilayered structure having multiplexed
transport packets in the highest layer. The determination information is inserted into,
for example, those packets of the multilayered structure which are the packets of
some or all of the layers thereof.