1、 International Telecommunication Union ITU-T T.832TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (01/2012) SERIES T: TERMINALS FOR TELEMATIC SERVICES Still-image compression JPEG XR Information technology JPEG XR image coding system Image coding specification Recommendation ITU-T T.832 ITU-T T-SERI
2、ES RECOMMENDATIONS TERMINALS FOR TELEMATIC SERVICES Facsimile Framework T.0T.19 Still-image compression Test charts T.20T.29 Facsimile Group 3 protocols T.30T.39 Colour representation T.40T.49 Character coding T.50T.59 Facsimile Group 4 protocols T.60T.69 Telematic services Framework T.70T.79 Still-
3、image compression JPEG-1, Bi-level and JBIG T.80T.89 Telematic services ISDN Terminals and protocols T.90T.99 Videotext Framework T.100T.109 Data protocols for multimedia conferencing T.120T.149 Telewriting T.150T.159 Multimedia and hypermedia framework T.170T.189 Cooperative document handling T.190
4、T.199 Telematic services Interworking T.300T.399 Open document architecture T.400T.429 Document transfer and manipulation T.430T.449 Document application profile T.500T.509 Communication application profile T.510T.559 Telematic services Equipment characteristics T.560T.649 Still-image compression JP
5、EG 2000 T.800T.829 Still-image compression JPEG XR T.830T.849Still-image compression JPEG-1 extensions T.850T.899 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T T.832 (01/2012) i Recommendation ITU-T T.832 Information technology JPEG XR image coding system Image c
6、oding specification Summary Recommendation ITU-T T.832 specifies a coded image format, referred to as JPEG XR, which is designed primarily for the storage and interchange of continuous-tone photographic content. The main body of the text specifies the syntax and semantics of JPEG XR coded images and
7、 the associated decoding process. Annex A specifies a tag-based file storage format for the storage and interchange of such coded images. Annex B specifies profiles and levels, which determine conformance requirements for classes of encoders and decoders. Aspects of color imagery representations and
8、 color management are discussed in Annex C. The typical expected encoding process is described in Annex D. The first edition of Recommendation ITU-T T.832 was approved in 03/2009. Corrigendum 1 (approved 12/2009) contained a set of various minor corrections. Corrigendum 2 (approved 05/2011) containe
9、d additional minor corrections. This revised edition (approved 01/2012) includes additional minor corrections. This text was developed as a twin text Recommendation corresponding to ISO/IEC 29199-2 in collaboration with ISO/IEC JTC 1/SC 29/WG 1 (JPEG). History Edition Recommendation Approval Study G
10、roup 1.0 ITU-T T.832 2009-03-16 16 1.1 ITU-T T.832 (2009) Cor.1 2009-12-14 16 1.2 ITU-T T.832 (2009) Cor. 2 2011-05-14 16 2.0 ITU-T T.832 2012-01-13 16 ii Rec. ITU-T T.832 (01/2012) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of tele
11、communications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing teleco
12、mmunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered by the pr
13、ocedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a te
14、lecommunication administration and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicability) and compliance with the Recommendation is achieved when all of
15、 these mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTS
16、 ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU m
17、embers or others outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not
18、 represent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2012 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T T.832 (
19、01/2012) iii CONTENTS Page Introduction . xvii 1 Scope 1 2 Normative references . 1 3 Definitions 1 4 Abbreviations . 4 5 Conventions 5 5.1 Conformance language 5 5.2 Operators . 5 5.2.1 Arithmetic operators 5 5.2.2 Logical operators . 6 5.2.3 Relational operators 6 5.2.4 Bit-wise operators . 6 5.2.
20、5 Assignment operators 7 5.2.6 Precedence order of operators . 7 5.2.7 Pseudocode operations 7 5.2.8 Mathematical functions . 9 5.3 Syntax and semantics notation 11 5.3.1 Method of specifying syntax in tabular form 11 5.3.2 SYNTAX_ELEMENT_EXAMPLE semantics . 12 5.3.3 Syntax functions 12 5.4 Formatti
21、ng conventions . 12 5.4.1 Variable and array naming conventions 12 5.4.2 Data structure naming conventions . 13 5.4.3 Syntax element naming conventions . 13 5.4.4 Syntax structure naming conventions 13 5.4.5 Naming conventions for mnemonic constants 13 5.4.6 Naming conventions for numerical values 1
22、3 5.4.7 Array dimensions convention 13 5.5 Global variables 14 5.5.1 Image variables . 14 5.5.2 Image plane variables 14 5.5.3 Tile variables . 15 5.5.4 Macroblock variables 15 5.5.5 Data structures for adaptive VLC table selection 16 5.5.6 Adaptive coefficient normalization data structure instances
23、 . 18 5.5.7 Adaptive CBPHP prediction data structure instance . 18 5.5.8 Adaptive count CBPLP variables 19 5.6 Adaptive VLC deltaDisc tables . 19 5.7 Adaptive inverse scanning tables 19 6 Image and codestream structures 20 6.1 General 20 6.2 Image planes and component arrays . 20 6.3 Image windowing
24、 20 6.4 Image partitioning . 21 6.5 Transform coefficients and frequency bands 21 6.6 Codestream structure . 22 6.7 Precision and word length . 23 iv Rec. ITU-T T.832 (01/2012) 7 Overview of decoder 23 7.1 General 23 7.2 Overview of parsing process . 24 7.2.1 Overview of image layer codestream parsi
25、ng . 24 7.2.2 Overview of tile layer codestream parsing 24 7.2.3 Overview of macroblock layer codestream parsing 24 7.3 Overview of the decoding process 24 7.3.1 Overview of coefficient mapping 24 7.3.2 Overview of coefficient prediction 25 7.3.3 Overview of dequantization 25 7.3.4 Overview of sampl
26、e reconstruction . 25 7.3.5 Overview of output formatting 26 8 Syntax, semantics, and parsing process 26 8.1 General 26 8.2 CODED_IMAGE( ) 27 8.2.1 Syntax structure . 27 8.2.2 SubsequentBytes . 27 8.2.3 RESERVED_A_BYTE . 27 8.2.4 VLW_ESC( ) . 28 8.3 IMAGE_HEADER( ) 29 8.3.1 Syntax structure . 29 8.3
27、.2 GDI_SIGNATURE . 29 8.3.3 RESERVED_B . 30 8.3.4 HARD_TILING_FLAG 30 8.3.5 RESERVED_C . 30 8.3.6 TILING_FLAG . 30 8.3.7 FREQUENCY_MODE_CODESTREAM_FLAG 30 8.3.8 SPATIAL_XFRM_SUBORDINATE . 30 8.3.9 INDEX_TABLE_PRESENT_FLAG 31 8.3.10 OVERLAP_MODE . 31 8.3.11 SHORT_HEADER_FLAG . 31 8.3.12 LONG_WORD_FLA
28、G . 31 8.3.13 WINDOWING_FLAG 32 8.3.14 TRIM_FLEXBITS_FLAG 32 8.3.15 RESERVED_D . 32 8.3.16 RED_BLUE_NOT_SWAPPED_FLAG . 32 8.3.17 PREMULTIPLIED_ALPHA_FLAG 33 8.3.18 ALPHA_IMAGE_PLANE_FLAG . 33 8.3.19 OUTPUT_CLR_FMT . 34 8.3.20 OUTPUT_BITDEPTH 34 8.3.21 WIDTH_MINUS1 . 35 8.3.22 HEIGHT_MINUS1 . 35 8.3.
29、23 NUM_VER_TILES_MINUS1 35 8.3.24 NUM_HOR_TILES_MINUS1 . 35 8.3.25 TILE_WIDTH_IN_MBn 35 8.3.26 TILE_HEIGHT_IN_MBn 36 8.3.27 TOP_MARGIN . 36 8.3.28 LEFT_MARGIN . 36 8.3.29 BOTTOM_MARGIN 36 8.3.30 RIGHT_MARGIN 37 8.4 IMAGE_PLANE_HEADER( ) . 37 8.4.1 Syntax structure . 37 8.4.2 INTERNAL_CLR_FMT . 38 8.
30、4.3 SCALED_FLAG . 38 8.4.4 BANDS_PRESENT 38 8.4.5 RESERVED_E_BIT . 39 8.4.6 CHROMA_CENTERING_X 39 8.4.7 RESERVED_F 39 Rec. ITU-T T.832 (01/2012) v 8.4.8 RESERVED_G_BIT . 39 8.4.9 CHROMA_CENTERING_Y 40 8.4.10 RESERVED_H . 40 8.4.11 NUM_COMPONENTS_MINUS1 40 8.4.12 NUM_COMPONENTS_EXTENDED_MINUS16 40 8.
31、4.13 SHIFT_BITS . 41 8.4.14 LEN_MANTISSA . 41 8.4.15 EXP_BIAS 41 8.4.16 DC_IMAGE_PLANE_UNIFORM_FLAG . 41 8.4.17 RESERVED_I_BIT 41 8.4.18 LP_IMAGE_PLANE_UNIFORM_FLAG . 41 8.4.19 RESERVED_J_BIT 41 8.4.20 HP_IMAGE_PLANE_UNIFORM_FLAG . 41 8.4.21 BYTE_ALIGNMENT_BIT 41 8.4.22 DC_QP( ) 42 8.4.23 LP_QP( ) .
32、 43 8.4.24 HP_QP( ) . 43 8.5 INDEX_TABLE_TILES( ) . 44 8.5.1 Syntax structure . 44 8.5.2 INDEX_TABLE_STARTCODE 44 8.5.3 IndexOffsetTilen . 44 8.6 PROFILE_LEVEL_INFO( ) . 45 8.6.1 Syntax structure . 45 8.6.2 PROFILE_IDC 45 8.6.3 LEVEL_IDC . 45 8.6.4 RESERVED_L 45 8.6.5 LAST_FLAG 45 8.7 CODED_TILES( )
33、 46 8.7.1 Syntax structure . 46 8.7.2 TILE_SPATIAL( ) 47 8.7.3 TILE_DC( ) . 48 8.7.4 TILE_HEADER_DC( ) . 48 8.7.5 TILE_LOWPASS( ) 49 8.7.6 TILE_HEADER_LOWPASS( ) 49 8.7.7 TILE_HIGHPASS( ) . 50 8.7.8 TILE_HEADER_HIGHPASS( ) . 51 8.7.9 TILE_FLEXBITS( ) 51 8.7.10 Tile-level semantics 51 8.7.11 MB_DC( )
34、 . 54 8.7.12 DECODE_DC( ) . 55 8.7.13 DECODE_ABS_LEVEL( ) . 55 8.7.14 Macroblock DC( ) semantics . 56 8.7.15 Macroblock low-pass 57 8.7.16 General 57 8.7.17 Coded block pattern high-pass (CBPHP) 61 8.7.18 Macroblock high-pass . 67 8.7.19 Macroblock FLEXBITS 75 8.8 Adaptive VLC code table selection .
35、 76 8.8.1 General 76 8.8.2 Adaptive VLC deltaDisc tables . 77 8.8.3 Initialization 79 8.8.4 Update of adaptive VLC code table selection . 81 8.9 Adaptation of CBPLP state variables 83 8.9.1 General 83 8.9.2 InitializeCountCBPLP( ) . 83 8.9.3 UpdateCountCBPLP( ) 84 8.10 Adaptive CBPHP prediction . 84
36、 8.10.1 InitializeCBPHPModel( ) 84 8.10.2 UpdateCBPHPModel( ) 84 vi Rec. ITU-T T.832 (01/2012) 8.11 Adaptive inverse scanning 85 8.11.1 Adaptive inverse scanning tables 85 8.11.2 InitializeAdaptiveScanLP( ) 85 8.11.3 InitializeAdaptiveScanHP( ) . 86 8.11.4 ResetTotalsAdaptiveScanLP( ) . 86 8.11.5 Re
37、setTotalsAdaptiveScanHP( ) . 86 8.11.6 AdaptiveLPScan( ) 87 8.11.7 AdaptiveHPScan( ) 87 8.12 Adaptive coefficient normalization . 88 8.12.1 InitializeModelMB( ) 88 8.12.2 UpdateModelMB( ) . 88 9 Decoding process . 89 9.1 General 89 9.2 Image decoding . 89 9.3 Image plane decoding . 90 9.4 Tile trans
38、form coefficient processing 90 9.4.1 Overview . 90 9.4.2 DC transform coefficient decoding . 91 9.4.3 Low-pass transform coefficient decoding . 91 9.4.4 High-pass transform coefficient decoding. 91 9.5 Coefficient remapping . 92 9.5.1 DC coefficient remapping . 92 9.5.2 Low-pass coefficient remappin
39、g . 92 9.5.3 High-pass macroblock coefficient remapping . 93 9.5.4 High-pass block coefficient remapping . 93 9.6 Transform coefficient prediction . 94 9.6.1 DC coefficient prediction 94 9.6.2 Low-pass prediction 96 9.6.3 High-pass prediction . 98 9.7 Derivation of quantization parameters 102 9.7.1
40、Derivation of DC quantization parameters 102 9.7.2 Derivation of low-pass quantization parameters . 103 9.7.3 Derivation of high-pass quantization parameters 104 9.8 Dequantization 105 9.8.1 Dequantization of DC coefficients 105 9.8.2 Dequantization of low-pass coefficients . 106 9.8.3 Dequantizatio
41、n of high-pass coefficients 106 9.8.4 QuantMap( ) 107 9.9 Sample reconstruction . 108 9.9.1 Overview . 108 9.9.2 First level inverse transform 108 9.9.3 First level overlap filtering 109 9.9.4 Second level coefficient combination . 121 9.9.5 Second level inverse transform . 122 9.9.6 Second level ov
42、erlap filtering . 123 9.9.7 Inverse transform basic operations 129 9.9.8 Overlap filtering functions 132 9.10 Output formatting 136 9.10.1 Overview . 136 9.10.2 Output formatting stage . 136 9.10.3 Sampling conversion . 137 9.10.4 Conversion from INTERNAL_CLR_FMT to OUTPUT_CLR_FMT 139 9.10.5 AddBias
43、( ) . 142 9.10.6 ComputeScaling( ) 143 9.10.7 Postscaling process 144 9.10.8 Clipping and packing stage . 146 Rec. ITU-T T.832 (01/2012) vii Annex A Tag-based file format . 150 A.1 General 150 A.2 Normative references 150 A.2.1 Identical Recommendations | International Standards 150 A.2.2 Paired Rec
44、ommendations | International Standards equivalent in technical content . 150 A.2.3 Additional references 150 A.3 Definitions . 150 A.4 Abbreviations 151 A.5 FILE_HEADER( ) 151 A.5.1 Syntax structure . 151 A.5.2 FIXED_FILE_HEADER_II_2BYTES . 151 A.5.3 FIXED_FILE_HEADER_0XBC_BYTE 151 A.5.4 FILE_VERSIO
45、N_ID . 151 A.5.5 FIRST_IFD_OFFSET . 151 A.6 IMAGE_FILE_DIRECTORY( ) . 152 A.6.1 Syntax structure . 152 A.6.2 NUM_ENTRIES . 152 A.6.3 ZERO_OR_NEXT_IFD_OFFSET . 152 A.7 IFD_ENTRY( ) . 152 A.7.1 Syntax structure . 152 A.7.2 FIELD_TAG . 154 A.7.3 ELEMENT_TYPE 154 A.7.4 NUM_ELEMENTS . 155 A.7.5 VALUES_OR
46、_OFFSET . 155 A.7.6 DOCUMENT_NAME 155 A.7.7 IMAGE_DESCRIPTION 155 A.7.8 EQUIPMENT_MAKE 155 A.7.9 EQUIPMENT_MODEL . 155 A.7.10 PAGE_NAME 156 A.7.11 PAGE_NUMBER . 156 A.7.12 SOFTWARE_NAME_VERSION 156 A.7.13 DATE_TIME 156 A.7.14 ARTIST_NAME . 157 A.7.15 HOST_COMPUTER . 157 A.7.16 COPYRIGHT_NOTICE . 157
47、 A.7.17 COLOR_SPACE . 158 A.7.18 PIXEL_FORMAT . 158 A.7.19 SPATIAL_XFRM_PRIMARY . 166 A.7.20 IMAGE_TYPE 166 A.7.21 PTM_COLOR_INFO( ) 167 A.7.22 PROFILE_LEVEL_CONTAINER( ) . 172 A.7.23 IMAGE_WIDTH 172 A.7.24 IMAGE_HEIGHT . 172 A.7.25 WIDTH_RESOLUTION 172 A.7.26 HEIGHT_RESOLUTION . 172 A.7.27 IMAGE_OF
48、FSET . 172 A.7.28 IMAGE_BYTE_COUNT 172 A.7.29 ALPHA_OFFSET . 173 A.7.30 ALPHA_BYTE_COUNT . 173 A.7.31 IMAGE_BAND_PRESENCE 173 A.7.32 ALPHA_BAND_PRESENCE 173 A.7.33 PADDING_DATA 173 Annex B Profiles and Levels . 175 B.1 General 175 B.2 Profiles 175 B.2.1 Sub-Baseline profile 175 B.2.2 Baseline profil
49、e . 175 viii Rec. ITU-T T.832 (01/2012) B.2.3 Main profile . 175 B.2.4 Advanced profile . 176 B.2.5 Reserved values of PROFILE_IDC 176 B.3 Levels 176 Annex C Color imagery representation and color management 178 C.1 Background information . 178 C.2 Color interpretation in the JPEG XR context 178 Annex D Encoder processing 181 D.1 Overview . 181 D.2 Pre-scaling . 181 D.3 Color conversion . 183 D.3.1 General 183 D.3.2 FwdColorFmtConvert1( ) 183 D.3.3 FwdColorFmtConvert2( ) 183 D.3.4 FwdColorFmtConvert3( ) 184 D.3.5 Macroblock a
