1、INTERNATIONAL STANDARD ISO/IEC 14496-2 Second edition 2001-12-01 AMENDMENT 1 2002-02-01 Information technology - Coding of audio-visual objects - Part 2: Visual AMENDMENT 1 : Studio profile Technologies de linformation - Codage des objets audiovisuels - Partie 2: Codage visuel AMENDEMENT 1: Profil d
2、u studio Adopted by INCITS (InterNational Committee for Information Technology Standards) as an American National Standard. Date of ANSI Approval: 1/2/2003 Published by American National Standards Institute, 25 West 43rd Street, New York, New York 10036 Copyright 2002 by Information Technology Indus
3、try Council (ITI). All rights reserved. These materials are subject to copyright claims of International Standardization Organization (ISO), International Electrotechnical Commission (IEC), American National Standards Institute (ANSI), and Information Technology Industry Council (ITI). Not for resal
4、e. No part of this publication may be reproduced in any form, including an electronic retrieval system, without the prior written permission of ITI. All requests pertaining to this standard should be submitted to ITI, 1250 Eye Street NW, Washington, DC 20005. Printed in the United States of America
5、Reference number ISOIIEC 14496-2:2001 /Amd.l:2002(E) 0 ISOIIEC 2002 ISO/IEC 196-2:2001/Amd.l:2002( E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are emb
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10、C 2002 -All rights reserved ISO/I EC 14496-2 :2001 /hd. 1 : 2002( E) Foreword IS0 (the International Organization for Standardization) and IEC (the International Electrotechnical Commission) form the specialized system for worldwide standardization. National bodies that are members of IS0 or IEC par
11、ticipate in the development of International Standards through technical committees established by the respective organization to deal with particular fields of technical activity. IS0 and IEC technical committees collaborate in fields of mutual interest. Other international organizations, governmen
12、tal and non-governmental, in liaison with IS0 and IEC, also take part in the work. In the field of information technology, IS0 and IEC have established a joint technical committee, ISO/IEC JTC 1. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3
13、. The main task of the joint technical committee is to prepare International Standards. Draft International Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as an International Standard requires approval by at least 75 % of the national bod
14、ies casting a vote. Attention is drawn to the possibility that some of the elements of this Amendment may be the subject of patent rights. IS0 and IEC shall not be held responsible for identifying any or all such patent rights. Amendment 1 to International Standard ISO/IEC 14496-2:2001 was prepared
15、by Joint Technical Committee ISO/IEC JTC 1, Information technology, Subcommittee SC 29, Coding of audio, picture, multimedia and hypermedia informa tion. O ISOIIEC 2002 -All rights reserved iii ISO/I EC 14496-2 :2001 /hd. 1 : 2002( E) Information technology - Coding of audio-visual objects - Part 2:
16、 Visual AMENDMENT I : Studio profile 1) Add the following text at the end of Overview of the object based non scalable syntax of Introduction: II In order to preserve the lossless quality, or to restrict the maximum bit count of block data, the block based DPCM coding can be used for ISO/IEC 14496-2
17、:2001 Amendment 1 (Studio Profile Amendment). 2) Replace text in Coding of Shapes of Introduction, II In natural video scenes, VOPs are generated by segmentation of the scene according to some semantic meaning. For such scenes, the shape information is thus binary (binary shape). Shape information i
18、s also referred to as alpha plane. The binary alpha plane is coded on a macroblock basis by a coder which uses the context information, II with II motion compensation andarithmetic coding. es, VOPs are generated by segmentation of the SCE In natural video SCE e according to some semantic meaning. Fo
19、r such scenes, the shape information is thuk binary (binary shape). Shape information is also referred to as alpha plane. The binary alpha plane is coded on a macroblock basis by a coder which uses the context information, motion compensation and arithmetic coding. For high quality applications, the
20、 uncompressed binary alpha block coding is used. 3) Add the following text in Introduction following Coding of Shapes: II Coding interlaced video Each frame of interlaced video consists of two fields which are separated by one field-period. This part of ISO/IEC 14496 allows either the frame to be en
21、coded as a VOP or the two fields to be encoded as two VOPs. Frame encoding or field encoding can be adaptively selected on a frame-by-frame basis. Frame encoding is typically preferred when the video scene contains significant detail with limited motion. Field encoding, in which the second field can
22、 be predicted from the first, works better when there is fast movement. O ISOIIEC 2002 -All rights reserved 1 ISO/IEC 196-2:2001/Amd.l:2002( E) 4) Replace text in Motion representation - macroblocks of Introduction, The choice of 16x16 blocks (referred to as macroblocks) for the motion-compensation
23、unit is a result of the trade- off between the coding gain provided by using motion information and the overhead needed to represent it. Each macroblock can further be subdivided to 8x8 blocks for motion estimation and compensation depending on the overhead that can be afforded. In order to encode t
24、he highly active scene with higher vop rate, a Reduced Resolution VOP tool is provided. When this tool is used , the size of the macroblock used for motion compensation decoding is 32 x 32 pixels and the size of block is 16 x 16 pixels. with II The choice of 16x16 blocks (referred to as macroblocks)
25、 for the motion-compensation unit is a result of the trade- off between the coding gain provided by using motion information and the overhead needed to represent it. Each macroblock can further be subdivided to 8x8 blocks for motion estimation and compensation depending on the overhead that can be a
26、fforded. In order to encode the highly active scene with higher vop rate, a Reduced Resolution VOP tool is provided. When this tool is used , the size of the macroblock used for motion compensation decoding is 32 x 32 pixels and the size of block is 16 x 16 pixels. In frame encoding, the prediction
27、from the previous reference frame can itself be either frame-based or field-based. 5) Replace text in Chrominance formats of Introduction, II This part of ISO/IEC 14496 currently supports the 4:2:0 chrominance format. with II This part of ISO/IEC 14496 currently supports the 4:2:0 chrominance format
28、. ISO/IEC 14496-2:2001 Amendment 1 also supports the 4:2:2 and 4:4:4 chorominance formats in addition. 6) Add the following text in Introduction following Chrominance formats: II RGB color components ISO/IEC 14496-2:2001 Amendment 1 supports coding of RGB color components. The resolution of each com
29、ponent shall be identical when input data is treated as RGB color components. 2 O ISO/IEC 2002 -All rights reserved ISO/I EC 14496-2 :2001 /hd. 1 : 2002( E) 7) Add the following text at the end of Pixel depth of Introduction: II ISO/IEC 14496-2:2001 Amendment 1 supports 8, 10 and 12 bits in luminanc
30、e and chrominance or RGB planes. II 8) Replace subclauses 3.38, 3.82, 3.107, and 3.131 with the following: II 3.38 3.82 3.107 3.131 II component: A matrix, block or single sample from one of the three matrices (luminance and two chrominance or green, blue and red color primaries) that make up a pict
31、ure. frame: A frame contains lines of spatial information of a video signal. For progressive video, these lines contain samples starting from one time instant and continuing through successive lines to the bottom of the frame. For interlaced video a frame consists of two fields, a top field and a bo
32、ttom field. One of these fields will commence one field period later than the other. macroblock: The four 8x8 blocks of luminance data and the two (for 4:2:0 chrominance format), four (for 4:2:2 chrominance format) or eight (for 4:4:4 chrominance format) corresponding 8x8 blocks of chrominance data
33、coming from a 16x16 section of the luminance component of the picture. Macroblock is sometimes used to refer to the sample data and sometimes to the coded representation of the sample values and other data elements defined in the macroblock header of the syntax defined in this part of ISO/IEC 14496.
34、 The usage is clear from the context. picture: Source, coded or reconstructed image data. A source or reconstructed picture consists of three rectangular matrices of N-bit numbers representing the luminance and two chrominance signals or rgb colour signals. A “coded VOP was defined earlier. For prog
35、ressive video, a picture is identical to a frame, while for interlaced video, a picture can refer to a frame, or the top field or the bottom field of the frame depending on the context. 9) Add the following subclauses in clause 3 and renumber the subsequent items. II 3.6 B-field VOP: A field structu
36、re B-VOP. 3.7 B-frame VOP: A frame structure B-VOP. 3.20 bottom field: One of two fields that comprise a frame. Each line of a bottom field is spatially located immediately below the corresponding line of the top field. 3.33 coded B-frame: A B-frame VOP or a pair of B-field VOPs that is coded. 3.34
37、coded frame: A coded frame is a coded I-frame, a coded P-frame or a coded B-frame. 3.35 coded I-frame: An I-frame VOP or a pair of field VOPs that is coded where the first field VOP is an I- VOP and the second field VOP is an I-VOP or a P-VOP 3.36 coded P-frame: A P-frame VOP or a pair of field VOPs
38、 that is coded. O ISOIIEC 2002 -All rights reserved 3 ISO/IEC 196-2:2001/Amd.l:2002( E) 3.42 coded order: The order in which the VOPs are transmitted and decoded. This order is not necessarily the same as the display order. 3.64 3.66 3.85 3.86 3.88 3.89 3.90 3.91 3.99 3.102 3.103 display aspect rati
39、o: The ratio heightwidth (in spatial measurement units such as centimeters) of the intended display. display process: The (non-normative) process by which reconstructed frames are displayed. fast forward playback: The process of displaying a sequence, or parts of a sequence, of VOPs in display-order
40、, faster than real-time. fast reverse playback: The process of displaying a sequence, or parts of a sequence, of VOPs in the reverse of display order, faster than real-time. field: For an interlaced video signal, a “field” is the assembly of alternate lines of a frame. Therefore an interlaced frame
41、is composed of two fields, a top field and a bottom field. field-based prediction: A prediction mode using only one field of the reference frame. The predicted block size is 16x16 luminance samples. Field-based prediction is not used in progressive frames. field period: The reciprocal of twice the f
42、rame rate. field VOP; field structure VOP: A field structure VOP is a coded VOP with vop-structure is equal to “Top field” or “Bottom field”. frame-based prediction: A prediction mode using both fields of the reference frame. frame VOP; frame structure VOP: A frame structure VOP is a coded VOP with
43、vop-structure is equal to “Frame”. future reference frame (field): A future reference frame (field) is a reference frame (field) that occurs at a later time than the current VOP in display order. 3.113 3.114 I-field VOP: A field structure I-VOP. I-frame VOP: A frame structure I-VOP. 3.147 RGB compon
44、ent: A matrix, block or single sample representing one of the three primary colours. The symbols used for the rgb signals are Green, Blue and Red. 3.148 3.149 P-field VOP: A field structure P-VOP. P-frame VOP: A frame structure P-VOP. 4 O ISO/IEC 2002 -All rights reserved ISO/I EC 14496-2 :2001 /hd.
45、 1 : 2002( E) while ( !bytealignedo ) zero-bit 3.171 sample aspect ratio: (abbreviated to SAR). This specifies the relative distance between samples. It is defined (for the purposes of this specification) as the vertical displacement of the lines of luminance samples in a frame divided by the horizo
46、ntal displacement of the luminance samples. Thus its units are (metres per line) + (metres per sample) 1 O 3.182 skipped macroblock: A macroblock for which no data is encoded. zero-byte 1 3.192 top field: One of two fields that comprise a frame. Each line of a top field is spatially located immediat
47、ely above the corresponding line of the bottom field. II 8 0000 0000 IO) Add the following subclause 5.2.9 after subclause 5.2.8: II 5.2.9 Definition of next-start-code-studio() function The next-start-code-studio() function removes any zero bit and zero byte stuffing and locates the next start code
48、. I next-start-code-studio() I No. of bits I Mnemonic I I while nextbits0 != O000 O000 O000 O000 O000 0001 1 I I I This function checks whether the current position is byte aligned. If it is not, zero stuffing bits are present. After that any number of zero stuffing bytes may be present before the s
49、tart code. Therefore start codes are always byte aligned and may be preceded by any number of zero stuffing bits. 1 1) Replace subclause 6.1.1 with the following: II 6.1.1 Visual object sequence Visual object sequence is the highest syntactic structure of the coded visual bitstream. A visual object sequence commences with a vicualobject-sequence-start-code which is followed by profile-and-level-indication, and one or more visual objects coded concurrently. The visual object sequence is term inated by a visualobject-sequence-end-code. At various poin
