1、1TU-T RECflN*T*83 74 4862593 Ob02788 051 INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU TERMINALS FOR TELEMATIC SERVICES T.83 (1 1 /94) INFORMATION TECHNOLOGY - DIGITAL COMPRESSION AND CODING COMPLIANCE TESTING OF- CONTINUOUS-TONE STILL IMAGES: ITU-T Reco
2、mmendation T.83 (Previously “CCIT Recommendation”) Foreword IT (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunications. The IT Telecommunication Standardization Sector (ITU-T) is a permanent organ of the IT. Some 179 member countries, 84 te
3、lecom operating entities, 145 scientific and industrial organizations and 38 international organizations participate in IT-T which is the body which sets world telecommunications standards (Recommendations). The approval of Recommendations by the Members of ITU-T is covered by the procedure laid dow
4、n in WTSC Resolution No. 1 (Helsinki, 1993). In addition, the World Telecommunication Standardization Conference (WTSC), which meets every four years, approves Recommendations submitted to it and establishes the study programme for the following period. In some areas of information technology which
5、fall within IT-Ts purview, the necessary standards are prepared on a collaborative basis with IS0 and IEC. The text of ITU-T Recommendation T.83 was approved on 11th of November 1994. The identical text is also published as ISO/IEC International Standard 10918-2. NOTE In this Recommendation, the exp
6、ression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. O IT 1995 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopyi
7、ng and microfilm, without permission in writing from the IT. ITU-T RECMN*T-B3 94 4862571 CONTENTS Ob02790 70T Summary . Introduction . 1 Scope 2 Normative references . 3 Definitions. abbreviations. symbols, and conventions . 4 General . 5 Compressed data format compliance testing 6 Encoder complianc
8、e tests . 7 Decoder compliance tests . I Annex A - Procedures for determining generic encoder and decoder compliance . Annex B - Quantization tables for generic compliance testing of DCT-based processes . Annex C - Compressed test data stream structure for generic decoder compliance tests . Annex D
9、- Construction of application-specific compliance tests Annex E - Compliance test data for testing of greater computational accuracy . Annex F - Specification of supported parameter ranges . Annex H - Examples and guidelines . Page 11 ii 1 1 1 4 6 19 20 25 28 30 51 53 55 58 ITU-T Rec . T.83 (1994 E)
10、 I ITU-T RECMN*TmB3 74 4862573 0602773 646 Summary This Recommendation I International Standard, Digital Compression und Coding of Continuous-tone Still Images, is published as two parts: IT-T Rec. T.81 i ISO/IEC 10918-1 “Requirements und guidelines” sets out requirements and implementation guidelin
11、es for continuous-tone still image encoding and decoding processes, and for the coded representation of compressed image data. These processes and representations are intended to be generic, that is, to be applicable to a broad range of applications for colour and grayscale still images within commu
12、nications and computer systems. This part, ITU-T Rec. T.83 i ISO/IEC 10918-2 “Compliance tes?ing” sets out tests for determining whether implementations comply with the requirements for the various encoding and decoding processes specified in IT-T Rec. T.81 I ISO/IEC 10918-1. ITU-T Rec. T.83 I ISO/I
13、EC 10918-2 also specifies tests for determining whether any specific instance of compressed data complies with the ITU-T Rec. T.81 I ISO/IEC 10918-1 specification for compressed data format. Introduction This Recommendation i International Standard, Digital Compression und Coding of Continuous-tone
14、Still Images, is published as two parts: - - -T Rec. T.81 I ISO/IEC 10918-1: Requirementsandguidelines. IT-T Rec. T.83 i ISO/IEC 10918-2: Compliance testing. IT-T Rec. T.81 I ISO/IEC 10918-1 sets out requirements and implementation guidelines for continuous-tone still image encoding and decoding pro
15、cesses, and for the coded representation of compressed image data. These processes and representations are intended to be generic, that is, to be applicable to a broad range of applications for colour and grayscale still images within communications and computer systems. This part, ITU-T Rec. T.83 I
16、 ISO/IEC 10918-2, sets out tests for determining whether implementations comply with the requirements for the various encoding and decoding processes specified in -T Rec. T.81 I ISO/IEC 10918-1. -T Rec. T.83 I ISO/IEC 10918-2 also specifies tests for determining whether any specific instance of comp
17、ressed data complies with the ITU-T Rec. T.81 I ISODEC 10918-1 specification for compressed data format. The committee which has prepared this Specification is the ISO/IEC JTCl/SC29/wGl Sub Group on PEG, also known as the Joint Photographic Experts Group (PEG). Both the committee and the two parts o
18、f this Specification continue to be known informally by the name PEG. The ?oint” in JPEG refers to the committees collaboration with the ITU-T SG8 Rapporteurs Group on Recommendation Q. 16. In this collaboration, WG1 has performed the work of selecting, developing, documenting, and testing the gener
19、ic compression processes. IT-T SG8 has provided the requirements which these processes must satisfy to be useful for specific image communications applications such as facsimile, videotex, and audiographic conferencing. This Specification is presented in accordance with the rules of IT-T and ISO/IEC
20、 JTC1 established by “Rules for presentation of ITU-T I ISO/IEC common text”. Annexes A, B, C, and D form an integral part of this Specification. Annexes E, F, G, and H are for information only. 11 IT-T Rec. T.83 (1994 E) ITU-T RECMN*T-83 94 = 4862591 Ob02792 582 ISO/IEC 10918-2 : 1995 (E) INTERNATI
21、ONAL STANDARD ITU-T RECOMMENDATION INFORMATION TECHNOLOGY - DIGITAL COMPRESSION AND CODING OF CONTINUOUS-TONE STILL IMAGES: COMPLIANCE TESTING 1 Scope This Recommendation I Intemational Standard is concerned with compliance tests for the continuous-tone still image encoding processes, decoding proce
22、sses, and compressed data formats specified in ITU-T Rec. T.81 I ISO/IEC 10918-1. This Specification: - - - - - specifies compliance tests for the ITU-T Rec. T.81 I ISO/IEC 10918-1 compressed data formats; specifies compliance tests for the ITU-T Rec. T.81 I ISO/IEC 10918-1 encoding processes; speci
23、fies compliance tests for the ITU-T Rec. T.81 I ISO/IEC 10918-1 decoding processes; specifies a method for constructing application-specific compliance tests; gives guidance and examples on how to implement these tests in practice. This Specification specifies nonnative generic compliance tests for
24、the ITU-T Rec. T.81 I ISO/IEC 10918-1 encoding and decoding processes. These compliance tests are applicable to “stand-alone” generic implementations of one or more of the encoding and decoding processes specified in ITU-T Rec. T.81 I ISO/IEC 10918-1. Among the purposes of these tests is to ensure t
25、hat generic encoder (and decoder) implementations compute the discrete cosine transform (DCT) and quantization functions with sufficient accuracy. 2 Normative references The following ITU-T Recommendations and International Standards contain provisions which, through reference in this text, constitu
26、te provisions of this Recommendation I International Standard. At the time of publication, the editions indicated were valid. All Recommendations and Standards are subject to revision, and parties to agreements based on this Recommendation I International Standard are encouraged to investigate the p
27、ossibility of applying the most recent editions of the Recommendations and Standards indicated below. Members of EC and IS0 maintain registers of currently valid International Standards. The Telecommunication Standardization Bureau of the ITU-T maintains a list of the currently valid IW-T Recommenda
28、tions. 2.1 Additional references - IS0 5807: 1985, Information processing - Documentation symbols and conventions for data, program and system flowcharts, program network charts and system resources charts. 3 Definitions, abbreviations, symbols, and conventions 3.1 Definitions For the purposes of th
29、is Specification, the following definitions apply. 3.1.1 3.1.2 3.1.3 3.1.4 (coding) process 1: Coding process with baseline sequential DCT, 8-bit sample precision. (coding) process 2: Coding process with extended sequential DCT, Huffman coding, 8-bit sample precision. (coding) process 3: Coding proc
30、ess with extended sequential DCT, arithmetic coding, each component is a two dimensional array of 8 x 8 blocks stored left-to-right, top-to-bottom order; each 8 x 8 block has 64 coefficients stored in zigzag order; and each coefficient is represented by two bytes, the most significant byte first. Th
31、is data includes the blocks which are padded to complete an MCU on the right and bottom of the image. (Distributed as part of the compliance test data.) 3.1.35 encoder reference test data: Quantized DCT coefficient data generated by the reference FDCT and reference quantizer from the source image te
32、st data to be used in the DCT-based encoder compliance tests. (Distributed as part of the compliance test data.). 3.1.36 generic: Applicable to a broad range of applications, i.e. application independent. 3.1.37 orthogonal representation: The 2-dimensional row-column format illustrated in Figure AS
33、in IT-T Rec. T.81 I ISO/iEC 10918-1. 3.1.38 quantized coefficient Validation data: Quantized DCT coefficient data generated from the source image validation test data to be used in the DCT-based encoder validation tests. (Distributed as part of the compliance test data.). 3.1.39 decoder reference te
34、st data. It consists of an entropy decoder, a dequantizer, and the reference IDCT. 3.1.40 reference DCT-based encoder: An embodiment of the DCT-based encoding processes which generated the DCT-based compressed image test data streams. It consists of the reference FDCT, the reference quantizer, and a
35、n entropy encoder. 3.1.41 reference forward discrete cosine transform; reference FDCT: A double precision (64-bit) floating point embodiment of the FDCT described in A.3.3 of IT-T Rec. T.81 I ISO/IEC 10918-1. reference DCT-based decoder: An embodiment of the DCT-based decoding processes which genera
36、tes the 3.1.42 embodiment of the IDCT described in A.3.3 of IT-T Rec. T.81 I ISO/iEC 10918-1. reference inverse discrete cosine transform; reference IDCT: A double precision (64-bit) floating point 3.1.43 reference quantizer: An embodiment of the quantization described in A.3.4 in ITU-T Rec. T.81 I
37、ISO/lEC 10918-1. 3.1.44 source image test data: The data sets to be used as input to the encoder compliance tests. This data is a sequence of pseudo-random numbers generated with uniform distribution over the range from O to 255. The algorithm used to generate this data is described in Annex A of CC
38、ITT Recommendation H.261. (This data is distributed as part of the compliance test data.). 3.1.45 abbreviated format compressed data. (Distributed as part of the compliance test data.) table specification test data (stream): Table specification data generated to test decoder compliance with 3.2 Abbr
39、eviations The abbreviations used in this Specification are listed below. 3.2.1 3.2.2 arith.: An abbreviation for arithmetic coding. Huff.: An abbreviation for Huffman coding. 3.3 Symbols The symbols used in this Specification are listed below. 3.3.1 Annex E. Bu: quantization value at the ith row and
40、 jth column in the quantization tables defined in Annex B, appears in 3.3.2 DF: differential frame flag, appears in flow charts in clause 5. ITU-T Rec T.83 (1994 E) 3 ITU-T RECMNaT.83 94 W 48b259L Ob02795 291 ISO/IEC 10918-2 : 1995 (E) 3.3.3 accuracy defined in Annex E. 3.3.4 33.5 3.3.6 3.3.7 3.3.8
41、3.3.9 33.10 3.3.11 3.3.12 appears in Table G. 1. 3.3.13 3.3.14 3.3.15 3.3.16 3.3.17 Eu: quantization value at the ith row and jth column in the quantization tables used in testing for greater F: the scale factor used to generate E, from Bij as defined in E.l. FS: first scan in frame flag, appears in
42、 flow charts in clause 5. G: guaranteed in compressed data, appears in Tables 1 to 5 in clause 5. H-L: hierarchical lossless processes, appears in Table G.l. H-S: hierarchical sequential DCT-based processes without final lossless scans, appears in Table G.l. HP: hierarchical progression flag, appear
43、s in flow charts in clause 5. LL: lossless processes, appears in Table G. 1. o: optional in compressed data, appears in tables in clause 5. P(FWLL): full progressive DCT-based processes with both spectral selection and successive approximation, P(SA): progressive DCT-based successive approximation p
44、rocesses, appears in Table G. 1, P(SS): progressive DCT-based spectral selection processes, appears in Table G.l. RI: restart interval flag, appears in flow charts in clause 5. S(B): baseline sequential DCT-based process, appears in Table G. 1. S(E): extended sequential DCT-based processes, appears
45、in Table G.l. 3.4 Conventions The flowcharts use the conventions given in IS0 5807. One of the conventions is that arrows are not needed when the flow is from left-to-right and from top-to-bottom. Arrows are sometimes used in such cases to increase clarity. 4 General The purpose of this clause is to
46、 give an informative overview of this Specification and the principles underlying it. Another purpose is to introduce some of the terms which are defined in clause 3. (Terms defined in clause 3 of ITU-T Rec. T.81 I ISO/IEC 10918-1 continue to apply in this Specification.) ITU-T Rec. T.83 I ISO/IEC 1
47、0918-2 concerns compliance testing for embodiments of the elements specified in ITU-T Rec. T.81 I ISOIIEC 10918-1. For encoders and decoders - embodiments of the ITU-T Rec. T.81 I ISOIIEC 10918-1 encoding and decoding processes - this document makes a distinction between GENERIC embodiments and APPL
48、ICATION-SPECIFIC embodiments. For the former, compliance tests themselves are specified herein; for the latter, this document specifies a method for defining compliance tests. Compliance tests are also specified for compressed data streams - embodiments of the ITU-T Rec. T.81 I ISO/IEC 10918-1 compr
49、essed data formats. NOTE - Like many compliance tests, those described in this Specification for generic encoders and decoders are not exhaustive tests of their respective functional specifications. Therefore, passing these tests does not guarantee complete functional correctness. This observation has two implications: 1) the tests do not fully guarantee complete interoperability between independently-implemented encoders and decoders; and 2) the tests for embodiments of the DCT-based processes do not guarantee that encoders or d
