JP2002238048A - Mpeg 2 transport stream transmission rate conversion method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease number of STC(system time clock) recovery circuits, when applying remultiplexing to a plurality of coded data. SOLUTION: A DEMUX section 108 demultiplexes a 1st TS(transport stream) packet H into a 2nd PSI(programmable specific information) packet and a 2nd TS packet J, a 2nd PSI generating section 110 interprets the contents of the 2nd demultiplexed PSI packet I and provides an output of a third PSI packet L that is regenerated. A PES(packetized elementary stream) time stamp replacing section 109 detects a packet including a PES header from the 2nd TS packet J, regenerates time stamp information from PCR(packet clock reference) information, the time stamp information and 2nd STC information K included in the packet, and outputs a 2nd packet M including the replaced time stamp information. A 2nd MUX section 112 inserts 2nd PCR information P to an adaptation field area prepared in advance, in the case of multiplexing a received third PSI packet L and a 2nd packet M.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission rate conversion method for an MPEG2 transport stream, and more particularly to a method for converting an MPEG2 transport stream input at an arbitrary transmission rate to another arbitrary transmission rate without impairing the contents. MPEG2 transport stream transmission rate conversion method.

[0002]

2. Description of the Related Art MPEG (Mo), which is a moving picture transmission standard, is used.
wing Picture Experts Grou
In the p) 2 standard, a transport stream (TS: TransportSt) is defined as a stream obtained by multiplexing a plurality of programs composed of a plurality of video and audio data.
stream) and program stream (PS: Progr)
amStream). It is also a basic element of both streams,
PES which is an intermediate stream for enabling a change between both streams: Packetized Elementary Stream (Packetized Elementary Stream)
Stream) packet is defined. The TS packet has a fixed length of 188 bytes and includes a 4-byte fixed-length packet header, a variable-length adaptation field, and a payload. The adaptation field of the packet header and the presence or absence of the payload are indicated by the adaptation field flag in the header. The adaptation field includes time management information PCR: Program Clock Ref, which defines the reception time on the decoding side.
There is a function of transmitting information such as information (information). The packet identification information (PID) includes a number for identifying a packet. One PES packet is inserted so as to start from the head of a plurality of TS packets having the same PID number.

[0003]

The conventional MPE described above.
The G2 transport stream transmission rate conversion method is as follows.
In the case where the data is changed to a data rate different from the transmission data rate at the time of encoding the video and audio encoded data in the MPEG-2 transport stream, the program clock reference PCR
(Program Clock Reference) information, a system time clock (STC: System Time Clock) at the time of encoding reproduced from information,
Time stamp information (TSI: TimeStampInfo) that gives information on the decoding time included in the encoded data
) and the system time clock (STC) of the data rate conversion system, it is necessary to generate and replace time stamp information. Therefore, when a plurality of transport streams encoded by different STCs are collectively multiplexed, an STC reproduction circuit is required for each input transport stream. Therefore, there is a problem that as the number of streams to be multiplexed increases, the number of STC reproduction circuits increases and the number of streams becomes complicated. SUMMARY OF THE INVENTION It is an object of the present invention to reduce the number of STC reproduction circuits when re-multiplexing a plurality of encoded data.
It is another object of the present invention to provide a method for converting a transmission rate of two transport streams.

[0004]

According to the present invention, there is provided an MPEG2 transport stream transmission rate conversion method comprising the steps of:
(Moving Picture Experts G
loop) 2 standard transport stream (TS:
Video (V) in TransportStream
When the encoded video data of the video (IDEO) and audio (AUDIO) is changed to a different transmission data rate than the transmission data rate at the time of encoding the encoded data of the video, the program time reference value (PCR: P
A time stamp (TimeS) that gives encoding time information from the program ClockReference information.
(Tamp) information is taken out and a reproduced system time clock (STC: SystemTimeClock) is taken out.
And a rate conversion unit that generates time stamp information to be replaced based on the relationship between the time stamp information and the system time stamp of the rate conversion system.
And the time stamp information indicating the decoding time included in the same TS packet.
Of the input coded data is converted using only the STC of the rate conversion system without reproducing.

[0005] A packetized elementary stream (PES: Packetized Elementen) is also used.
The TS including header stream information
2. The MPEG2 transport stream transmission rate conversion method according to claim 1, wherein adaptation field data for carrying the PCR information is added to a packet.

The encoding unit encodes a video signal of the input video and outputs the encoded data as encoded data. The encoded data is grouped in frame units. PTS: Pr
decoding time stamp (DT) that gives an esentation time stamp and a decoding start time.
Packetized elementary stream (PES: PacketizedElem) composed of S: DecodingTimeStamp information and a video stream
a PES header adding unit for adding an entry stream information and outputting as a first packet, and a system time clock (STC: System) for generating a time reference.
a first STC signal generating unit for generating and outputting a first STC signal of the "em Time Clock", and time stamp information (PES header information of the first packet) for determining a decoding time according to the first STC signal in the PES header information ( TSI: Tim
eStamp Information) is inserted and PE
The S data is cut out in units of TS packets, and the TS
T which adds header information and outputs it as a TS packet
And a program clock reference (PCR: Pr: Pr) which is time reference information for reproducing a reference time in which the reception time on the decoding side is defined by the first STC signal.
Ogram Clock Reference)
A first PCR generator that outputs the PCR information of the program, and program specification information (PSI: ProgramSpecific).
cInformation), a first PSI generator for outputting a first PSI packet of the first PSI packet, and an input first PSI packet.
When multiplexing the I packet and the TS packet,
An adaptation field (adap
1st MUX to which the first PCR information is added to the first MUX.
And a part.

In a rate converter, a second PSI packet of program specification information for inputting the first TS packet and converting a transmission rate and a second TS of video are used.
And a second PSI that interprets the contents of the input second PSI packet and newly regenerates and outputs it as a third PSI packet.
A generator, a second STC generator that generates and outputs a second STC signal of a system time clock, and detects a packet including PES header information from the input second TS packet, and A PES time stamp reordering unit that reorders the regenerated time stamp information based on the included PCR information, time stamp information, and the second STC signal, and outputs the PES time stamp information as a second packet; And a PCR replacement unit that generates and outputs second PCR information for use in the first and second PSI packets, and an adaptation field prepared in advance when multiplexing the third PSI packet and the second packet. And a second MUX section for replacing information and outputting the second TS packet as a second TS packet.

Also, stuff bytes are embedded in an adaptation field area of the first TS packet containing PCR information, and packet identification information (PID: Packet Id) for identifying a program different from video.
The second PCR information is loaded on the second TS packet having the authentication information and output.

Also, stuff bytes are embedded in an adaptation field area of the first TS packet including PCR information, and packet identification information (PID: Packet Id) for identifying a program different from video.
The third PCR information is placed on the second TS packet having the above (entification) and output.

[0010]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a block diagram of one embodiment of the present invention. For ease of explanation, the video (VI
Reference is made to FIG. 1 which handles one encoded data of a (DEO) signal.

The first-stage encoding unit of the present embodiment encodes a video signal of an input video A and outputs the encoded data B as encoded data B. The encoded data B is grouped in frame units. Time management information (PTS: Presentation Time St) for reproduction output
amp) and a decoding time stamp (DTS: DecodingTimeSta) that gives a decoding start time.
mp) information and a video stream, a packetized elementary stream (PES: Packet).
A PES header adding unit 104 for adding sized elementary stream information and outputting it as a first packet C, and a system time clock (STC: System) of a clock for generating a time reference for the encoder
A first STC generation unit 102 that generates and outputs a first STC signal D of “TimeClock”, and a first packet C
In the PES header information of the time stamp information (TSI: Tim) that determines the decoding time according to the first STC signal D.
e Stamp Information) is inserted and P
The ES data is transferred to the transport stream (T
S: Transport Stream) cut out in packet units, add TS header information (4 bytes), and
And a program clock reference (PCR: Program Cloth) which is time reference information for reproducing a reference time in which a reception time on the decoding side is defined by the first STC signal D and a TS conversion section 105 which outputs the packet as a packet E.
A first PCR generation unit 106 that outputs first PCR information F of ck Reference (ck Reference), and program specification information (PSI: Program Specific In).
first PSI generating section 103 for outputting a first PSI packet G of the first PSI
When multiplexing the packet G and the TS-converted packet E including the PES header information, the first PCR information F is added to an adaptation field prepared in advance and output as the first TS packet H And the MUX unit 107.

Next, in the rate converter, the first MU
The first TS packet H from the X unit 107 is input, and program specification information (PSI: Pro) for converting the transmission rate is input.
Gram Specific Information
n) a DEMUX unit 108 for separating and outputting a second PSI packet I and a second TS packet J for video;
Interpreting the contents of the input second PSI packet I,
A second PSI generator 110 that outputs a newly regenerated third PSI packet L, a second STC generator 111 that generates and outputs a second STC signal K of a system time clock, and A packet including PES header information is detected from the second TS packet J of the video, and the time stamp regenerated based on the PCR information, the time stamp (TimeStamp) information, and the second STC signal K included in the packet. PES time stamp reordering unit 1 that reorders information and outputs it as second packet M
09, a PCR replacement unit 113 that generates and outputs second PCR information P for replacement based on the second STC signal K,
An adaptation field (adaptat) prepared in advance when multiplexing an input second PSI packet L and a second TS packet M including PES header information.
second MUX unit 1 which replaces first PCR information P with the first PCR information P and outputs it as a second TS packet N
12.

FIG. 2 is a configuration diagram of a transport stream (TS) according to the present embodiment. A TS packet is a sync byte (47h), TS header information: 3 bytes, adaptation field information: 8 bytes, PES header information:
6 or 11 bytes, PES information: remaining (170 or
165 bytes).

Next, the operation of this embodiment will be described with reference to FIG. In the first stage encoding unit, the video signal of the input video A is encoded by the video data encoding unit 101.
The encoded data B is encoded by the PES header adding unit 10.
4 are grouped in frame units, and PE
The S header information is added and output as the first packet C. In the TS converter 105, the first STC generator 102
, The time stamp information that determines the decoding time is inserted according to the first STC signal D, and the PES-converted data is cut out in units of transport stream packets (TS packets), and TS header information (4 bytes) is added.
It is output as an encrypted packet E.

The first MUX unit 107 adds the adaptation field data carrying the first PCR information F from the first PCR generation unit 106 to the TS packet E including the PES header, and generates the first PSI generation data. First PSI packet G and TS of program specification information from unit 103
The multiplexing unit 105 appropriately selects the video TS conversion packet E from the multiplexing unit 105 and performs multiplexing. Here, when multiplexing the TS conversion packet E including the PES header, the first PCR generation unit 106
From the first PCR information F, and puts the PCR information F into an adaptation field prepared in advance. In the above process, the encoded data B is output as a TS packet H.

Next, in the data rate converter, the first
The first TS packet H from the MUX unit 107 of DE
The MUX unit 108 separates the second PSI packet I and the video second TS packet J. The content of the separated second PSI packet I is interpreted by the second PSI generating unit 110, and the second PSI packet I is newly regenerated and output as the third PSI packet L. PES time stamp replacement unit 10
9, the second TS packet J of the input video to PE
The packet including the S header is detected, and the PCR information and the time stamp information included in the packet are detected.
STC information K generated by the STC generator 111 of FIG.
, And regenerates the time stamp information, and outputs a second packet M including the replaced time stamp information. Second
Of the input third PSI packet L
And the second packet M from the PES time stamp reordering unit 109 are appropriately multiplexed. During this multiplexing, the first M
Similarly to the UX unit 107, the second PCR information P from the second PCR change unit 113 is inserted into an adaptation field area prepared in advance.

FIG. 3 is a block diagram of a second embodiment of the present invention. In the rate conversion unit, the first MUX unit 107
From the first TS packet H, and converts the transmission rate into program specification information (PSI: ProgramS
specificInformation) second PS
A DEMUX unit 108 for separating and outputting the I packet I and the video second TS packet J, and interpreting the contents of the input second PSI packet I, newly regenerating the third PSI packet A second PSI generator 110 that outputs as L, a second STC generator 111 that generates and outputs a second STC signal K of a system time clock,
A packet including PES header information is detected from the second TS packet J of the input video, and PCR information and a time stamp (Time St) included in the packet are detected.
amp) information and the second STC signal K, the PES time stamp replacing unit 109 that replaces the regenerated time stamp information and outputs the same as the second packet M, and the third STC signal K for replacement. When multiplexing a second PCR generation unit 114 that generates and outputs PCR information Q and a second packet M including PES header information and an input third PSI packet L, an adaptation field prepared in advance Second MUX that replaces the third PCR information Q with the second and outputs the second TS packet N
A part 112.

As described above, in the second embodiment, the PC shown in FIG.
Second PCR generation unit 1 in FIG. 3 instead of R replacement unit 113
14 has been replaced. In this case, the second MUX unit 11
In 2, the stuff byte is embedded in the adaptation field area of the TS packet including the PCR information. Second
In the PCR generation unit 114 of this example, packet identification information (PID: Packet) for identifying a packet different from video
The second TS with the t Identification
The third PCR information Q is put on the packet and output. This makes it possible to remultiplex a plurality of video and audio packets.

In the process of the first stage encoding unit, the PES header information adding unit 104 and the TS converting unit 105 convert the TS packet including the time stamp information (TSI) into a TS packet and a sync byte as shown in FIG. (47h), TS
Header information: 3 bytes, adaptation field information: 8 bytes, PES header information: 6 or 11 Byte
e, PES information: Remaining (170 or 165 bytes). Further, the first MUX unit 107 detects that a TS packet E including a PES header has entered, and
The first PCR information F is received from the PCR generation unit 106 of the above, and the first PCR information F is inserted into the adaptation field area of the TS packet E.

In the process of the rate conversion unit, the PES time stamp changing unit 109 and the second MUX unit 112 convert the video TS packet including the PES header into the PC
R information, time stamp information (TSI), and second STC
The second STC information K is received from the generation unit 111, and new time stamp information is generated by Expression (1). Time stamp information = (DTS-PCR) + STC -------
(1) In equation (1), DTS: decoding time stamp (DecodingTimeStamp) gives a decoding start time, and PCR: program clock reference (Program Clock Reference).
ce) is time management information indicating a reference time at which the reception time on the decoding side is defined, and is STC: System Time Clock, and the time stamp information generated by these is added to the PES header of the TS packet. The output is replaced with the included time stamp information.

In this way, the PCR information is reproduced from the PCR converter in the rate conversion unit which converts the encoded data of video and audio in the MPEG-2 transport stream to a data rate different from the transmission data rate at the time of encoding. When time stamp information is generated and replaced based on the relationship between the system clock (STC1) at the time of encoding, the time stamp information giving information on the decoding time included in the encoded data, and the system clock (STC2), the STC When multiplexing a plurality of coded transport streams together, an STC reproducing circuit is not necessary for the input transport stream, so that even if the number of streams to be multiplexed increases, the STC reproducing circuit does not need to be. It can be configured with less.

[0022]

As described above, according to the present invention, M
In the case where video data is transferred to a different transmission data rate from the transmission data rate at the time of encoding the video and audio encoded data in the PEG2 standard transport stream (TS), the time management information (PCR) is used. System time clock (S
TC), and retrieves time stamp information that gives decoding time information included in the encoded data, and generates time stamp information from the relationship between the reproduced STC, the time stamp information, and the system time clock of the rate conversion system. By replacing the encoded data, the number of STC reproducing circuits can be reduced when re-multiplexing a plurality of encoded data.

The reason is that there is no need to reproduce the STC at the time of encoding in the rate converter.

[Brief description of the drawings]

FIG. 1 is a block diagram of one embodiment of the present invention.

FIG. 2 is a configuration diagram of a transport stream including a PCR and a PER.

FIG. 3 is a block diagram of another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 101 Video data encoding unit 102 First STC generation unit 103 First PSI generation unit 104 PES header addition unit 105 TS conversion unit 106 First PCR generation unit 107 First MUX unit 108 DEMUX unit 109 With PES time stamp Replacement unit 110 second PSI generation unit 111 second STC generation unit 112 second MUX unit 113 PCR replacement unit 114 second PCR generation unit

Continued on front page F-term (reference) 5C059 KK31 MA00 PP04 RB02 RB09 RC04 RC32 SS06 SS30 UA01 UA04 5C063 AA01 AB07 AC01 BA01 CA23 CA29 CA36 CA40 DA07 DA13 DA20 5K028 AA07 EE03 MM16 5K034 AA11 CC02 CC05 KK28 MM

Claims (7)

[Claims] 1. An MPEG (Moving Picture)
e ExpertsGroup) 2 standard transport stream (TS: TransportStream)
m), when the video encoded data of the video (VIDEO) and the audio (AUDIO) is changed to the transmission data rate different from the transmission data rate at the time of encoding the encoded data of the video, the program time reference Reference value (PCR: ProgramClockRe
time stamp (TimeStamp) information that gives the time information of encoding from the F. information.
The reproduced system time clock (STC: System)
emTimeClock), PCR information for reproducing the STC at the time of encoding, and time stamp information indicating the decoding time in the rate conversion unit that generates time stamp information to be replaced based on the relationship between the time stamp information and the system time stamp of the rate conversion system. The MPEG-2 transport stream transmission rate conversion method characterized in that the rate conversion of the input coded data is performed using only the rate conversion STC without reproducing the STC at the time of encoding, by including the same in the same TS packet. 2. When multiplexing a plurality of TSs together,
Packetises Elementary Stream (PES: P
acknowledgmented ElementaryStream
m) adding the PCR to the TS packet including header information;
2. The MPEG2 transport stream transmission rate conversion method according to claim 1, wherein adaptation field data carrying information is added. 3. An encoding unit, which encodes a video signal of an input video and outputs the encoded data as encoded data, and collects the encoded data in units of frames. PTS: Prese
decoding time stamp (DTS: D) which gives a decoding start time and a decoding time stamp.
Packetized Elementary Stream (PES) consisting of encodingTimeStamp information and a video stream.
a PES header adding unit for adding a target stream and outputting the first packet, and a system time clock (STC: System) for generating a time reference.
A first STC signal generating unit for generating and outputting a first STC signal of the "Time Clock"; and time stamp information (TSI) for determining a decoding time according to the first STC signal in the PES header information of the first packet. : Time
(Stamp Information) is inserted and PES is inserted.
TS that cuts out the converted data into TS packets, adds TS header information, and outputs as TS converted packets
And a program clock reference (PCR: Pro :) which is time reference information for reproducing a reference time in which the reception time on the decoding side is defined by the first STC signal.
a first PCR generator for outputting first PCR information of a program clock reference (PGC), and program specification information (PSI: ProgramSpecific)
(Information) first PSI generating unit for outputting a first PSI packet, and an input first PSI packet.
When multiplexing a packet and the TS-converted packet, an adaptation field (adapt) prepared in advance is used.
and a first MUX unit for adding the first PCR information to a first field and outputting the first TS packet as a first TS packet. 4. The rate conversion section, wherein the first TS
A DEMUX unit that separates and outputs a second PSI packet of program specification information and a second TS packet of video for inputting a packet and converting a transmission rate, and interprets the content of the input second PSI packet. A second PSI generating unit for newly regenerating and outputting as a third PSI packet, a second STC generating unit for generating and outputting a second STC signal of a system time clock, 2), a packet containing PES header information is detected from the TS packets of the second STC signal, and the PCR information, the time stamp information included in the packet and the time stamp information regenerated by the second STC signal are replaced, and the packet is replaced as a second packet. A PES time stamp changing unit for outputting, and a P for generating and outputting second PCR information for replacement based on the second STC signal. And R Distribution unit, the third PS input
A second MUX unit that replaces the second PCR information in an adaptation field prepared in advance when multiplexing the I packet and the second packet and outputs the information as a second TS packet. Claim 3
The method for converting an MPEG2 transport stream transmission rate according to any one of the preceding claims. 5. The rate conversion section, wherein the first TS
A DEMUX unit that separates and outputs a second PSI packet of program specification information and a second TS packet of video for inputting a packet and converting a transmission rate, and interprets the content of the input second PSI packet. A second PSI generating unit for newly regenerating and outputting as a third PSI packet, a second STC generating unit for generating and outputting a second STC signal of a system time clock, 2), a packet including PES header information is detected from the TS packet of the second STC, and the time stamp information regenerated by the PCR information, the time stamp information, and the second STC signal included in the packet is replaced as a second packet. A PES time stamp changing unit for outputting, and a third PCR information for generating and outputting third PCR information for changing based on the second STC signal. A PCR generation unit of the third input
And a second MUX unit that replaces the third PCR information in an adaptation field prepared in advance when multiplexing the PSI packet and the second packet and outputs the second PCR packet as a second TS packet. 4. The method of converting an MPEG2 transport stream transmission rate according to claim 3, wherein: 6. A packet identification information (PID: Packet Iden) for embedding a stuff byte in an adaptation field area of the first TS packet including PCR information to identify a program different from a video.
5. The MPEG2 transport stream transmission rate conversion method according to claim 4, wherein the second PCR information is loaded on the second TS packet having the information, and is output. 7. A packet identification information (PID: Packet Identifier) for embedding a stuff byte in an adaptation field area of the first TS packet including PCR information to identify a packet different from a video.
6. The MPEG2 transport stream transmission rate conversion method according to claim 5, wherein the third PCR information is placed on the second TS packet having the information and the third PCR information is output.