1、STD-SMPTE 327tl-ENGL 2000 8357903 0004037 OTb W SMPTE STANDARD SMPTE 327M-2000 for Television - MPEG-2 Video Recoding Data Set Table of contents Scope Normative references General Definitions Picture rate information Macroblock rate information Transport of the MPEG-2 recoding data set Compressed st
2、ream format for bandwidth reduced systems Annex A Transport mechanisms Annex B Bibliography 1 Scope This standard specifies the content of the picture related recoding data set for the representation of ISO/IEC 13818-2 MPEG coding information for the purpose of optimally cascading decoders and recod
3、ers at any bit rate or GOP structure. The coding information is as derived from an ISOAEC 13818 compliant MPEG bit stream during the picture decod- ing process, as described in ISO/IEC 13818-2. The scope and operation of this standard are the definition of the content of a sufficient recoding data s
4、et which may be derived in decoders that comply with ISO/IEC 13818-2, including all nonscalable profiles defined in ISOAEC 13818-2. To allow the resynchronization of the video and its associated audio or data after processing, a mecha- nism using some additional information derived from ISO/IEC 1381
5、 8-1 is also included in this standard. This sufficient data set may be transported by various means defined in other SMPTE standards. Pagel ot9pageJs 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this standard. At t
6、he time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent edition of the standards indicated below. ITU-T H.222.0 with amend 1-2, ISOilEC
7、 13818- 1 :1996, Information Technology - Generic Coding of Moving Pictures and Associated Audio Information - Part 1 : Systems TU-T H.262 with amend l/corr 1 and amend 2lcorr 2, ISOAEC 1381 8-2:1996, Information Technology - Generic Coding of Moving Pictures and Associated Audio Information - Part
8、2: Video 3 General The principal application of this standard is to pre- serve the quality of the video signal when cascading MPEG-2 decoders and coders (including transding) by feeding forward previous coding decisions. The MPEG-2 recoding data set is described as suffi- cient when it contains the
9、data required that, in com- bination with an MPEG-2 decoded or partially decoded picture, allows bit accurate recreation of the previously picture coded bit stream. The various methods whereby the data set is trans- ported alongside the MPEG-2 decoded or partially decoded picture information are the
10、 subject of other standards. Copyright Q 2OM) by THE SOClEFy OF MOTION PICTURE AND TELEVISION ENGINEERS 595 W. HaMale Ave white Plains NY 10607 (914) 761-llW COPYRIGHT Society of Motion Picture otherwise it is set to O. 14-bit ui Set to the number of bits used by all codes in the syntax elements cod
11、ed-blockpattern() and block(), within the syntax element macroblock(), defined in clause 6.2.5 of Set to the number of bits used by all codes in the syntax elements motion-vectors(0) and motion-vectors(1) within ISOAEC 1381 8-2. 6-bit Ui Set to the number of bits used in the syntax element 7-bit Ui
12、Of ISOAEC 1381 8-2. 2-bit Ui the syntax element macroblock(), defined in clause 6.2.5 macroblock(), defined in clause 6.2.5 of ISOAEC 1381 8-2, excluding those codes accounted for by num-mv-bits and num-coef-bits. 7 Transport of the MPEG-2 recoding data set The previous clauses describe the necessar
13、y infor- mation for the sufficient MPEG-2 recoding data set. However, additional information and suitable trans- port mechanisms are required in order to be able to fully exploit this information in practical systems. The following additional information shall be available in all transport mechanism
14、s: - User data: This is unbounded by ISO/IEC 1381 8- 2. Adefined capacity shall be made available by the transport system employed, so that essential elements can be passed with the MPEG-2 recoding data set. - Copyright: The copyright extension defined in ISOAEC 1381 8-2 is not necessary for cascadi
15、ng operations. However, it is necessary that this infor- mation should be propagated through the system and it, therefore, forms an integral part of the standard. 7.1 Additional information derived from a packetized elementary stream Where the original source was derived from a packet- zed elementar
16、y stream, the following additional infor- mation must be included: - PTS/DTS as defined in ISO/IEC 1381 8-1. As audio, video, and other services are frequently split apart and pass through independent signal proc- essing paths, it is necessary to add this information to enable the reconstruction of
17、the complete stream after such processing. 7.2 Additional information derived from an elementary stream Where this information is derived from an elementary stream, the appropriate mechanism is described in SMPTE 328M. 8 Compressed stream format for band- width reduced systems There are, however, ci
18、rcumstances in which the trans- mission of the sufficient data set described in this Page 6 of 9 pages COPYRIGHT Society of Motion Picture - Temporal alignment of the decoded video and the MPEG-2 recodng data set on a macroblock and picture basis; - A system to accompany or embed this information in
19、to the ITU-R BT.601 stream without adversely affecting the picture quality for standard definition systems and a similar system for high-definition systems; - This system must also allow the MPEGP recoding data set to be destroyed m the areas of the picture where two or more video signals overlap. F
20、or this type of transport mechanism, all macroblock rate information must be available on a macroblock basis. If in the MPEG-2 decoding process, there is a need to derive or infer certain elements for use in the decoding of the current macroblock (e.g., skipped macroblock), then all the elements des
21、cribed in clause 6 must be set to those used by the decoding process, as defined in ISOllEC 1381 8-2. A full description of the standard defined version of this transport mechanism is given in SMPTE 319M. A2 History information There are instances where a video signal is first coded by a long GOP, l
22、ow bit rate coder to get the cost benefit of the source media. This may then be converted to a short GOP, high bit rate stream to get functional benefits, such as split- ing and VTR stunt play modes. The short GOP signal may then be converted back to a long GOP low bit rate stream at the output. In
23、such cases, conversion may be done in the compressed domain and it is useful to keep the first set of long GOP coding data present in the short GOP compressed bit stream and pass this to the next compression recoder to achieve the best picture quality at each generation. The carriage of this recodin
24、g data from the last but one encoder is called history recoding data. For the reasons outlined in clause 8, a bandwidth limited recoding data set may also be required for this history. It is also clear that the history recoding data may be carried either in the baseband (ITU-R BT.601 for standard de
25、finition signals) domain or the compressed bit stream domain de- pending on the application. Methods for the carriage of history recoding data will be required for both the baseband and bit stream domains. The system required to reduce the bandwidth is described in SMPTE 329M. The method of transpor
26、ting this signal in the baseband domain is defined in SMPTE 319M. Page 8 ot 9 pages COPYRIGHT Society of Motion Picture & Television EngineersLicensed by Information Handling ServicesSTD-SMPTE 327“ENGL 2000 8357403 0004047 172 SMPTE 327M-2OOO MPEG-2 Recoding Data Set Logical Level Recoding Data Set
27、L Transporting MPEGP Recoding Information through 4:2:2 Component Digital Interfaces Elementary Stream Editing Information Tnport Of MPEGP Recoding Information through AES Audio Channel Figure A.l- Relationships among SMPTE standards Annex B (informative) Bibliography SMPTE 319M-2000, Television - T
28、ransporting MPEG-2 Re- SMPTE 329M-2000, Television - MPEG-2 Video Recoding coding Information through 4:2:2 Component Digital Inter- Data Set - Compressed Stream Format faces ITU-R BT.601-5 (1994), Studio Encoding Parameters of SMPTE 328M-2000, Television - MPEG-2 Video Elemen- Digital Television for Standard 4:3 and Wide-Screen 16:9 tary Stream Editing Information Aspect Ratios Page 9 of 9 pages COPYRIGHT Society of Motion Picture & Television EngineersLicensed by Information Handling Services
