1、 International Telecommunication Union ITU-T J.144TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (03/2004) SERIES J: CABLE NETWORKS AND TRANSMISSION OF TELEVISION, SOUND PROGRAMME AND OTHER MULTIMEDIA SIGNALS Measurement of the quality of service Objective perceptual video quality measurement techn
2、iques for digital cable television in the presence of a full reference Recommendation ITU-T J.144 Rec. ITU-T J.144 (03/2004) i Recommendation ITU-T J.144 Objective perceptual video quality measurement techniques for digital cable television in the presence of a full reference Summary Recommendation
3、ITU-T J.144 provides guidelines on the selection of appropriate objective perceptual video quality measurement equipment designed for use in digital cable television applications when the full reference video signal is available. The validation test material did not contain channel errors. This Reco
4、mmendation defines objective computational models that have been shown to be superior to peak signal to noise ratio (PSNR) as automatic measurement tools for assessing the quality of video. This revised Recommendation includes four objective methods for the assessment of perceptual video quality in
5、the normative section. Source Recommendation ITU-T J.144 was approved on 15 March 2004 by ITU-T Study Group 9 (2001-2004) under Recommendation ITU-T A.8 procedure. ii Rec. ITU-T J.144 (03/2004) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the f
6、ield of telecommunications, 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 standard
7、izing telecommunications 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 cover
8、ed by the procedure 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 indica
9、te both a telecommunication 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 w
10、hen all of 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 PROPE
11、RTY RIGHTS 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 asserte
12、d by ITU members 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 th
13、is may not represent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2009 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU
14、-T J.144 (03/2004) iii CONTENTS Page 1 Scope 1 1.1 Application . 1 1.2 Limitations 1 2 References. 2 2.1 Normative references 2 2.2 Informative references 2 3 Terms, definitions and acronyms 2 4 User requirements. 3 5 Description of the full reference measurement method 3 6 Findings of the Video Qua
15、lity Experts Group (VQEG) . 4 7 Conclusions 5 7.1 Recommendation general advice 5 7.2 Objective video quality models Pathway to future revisions 6 Annex A British Telecommunications plc Full reference video quality model functional description . 7 A.1 Introduction 7 A.2 BT full-reference model . 7 A
16、.3 Detectors. 7 A.4 Integration. 15 A.5 Registration. 16 A.6 References 16 A.7 Subjective and objective data . 17 Annex B Yonsei University/SK Telecom/Radio Research Laboratory Full reference video quality model functional description 21 B.1 Introduction 21 B.2 Objective measurement of video quality
17、 based on edge degradation 21 B.3 Registration. 32 B.4 Conclusion 35 B.5 References 35 Annex C Telecommunications Research and Development Center (CPqD) Image Evaluation based on Segmentation (IES) technical description. 40 C.1 Introduction 40 C.2 General description of the CPqD-IES algorithm 40 C.3
18、 Correction of offset and gain 42 C.4 Image segmentation 43 C.5 Objective measurement 45 C.6 Database of impairment models . 46 C.7 Estimation of impairment models 48 iv Rec. ITU-T J.144 (03/2004) Page C.8 References 50 C.9 Objective results in VQEG-phase II tests. 51 Annex D National Telecommunicat
19、ions and Information Administration (NTIA) Video Quality Metric (VQM) technical description . 52 D.1 Introduction 52 D.2 References 52 D.3 Definitions 52 D.4 Overview of the Video Quality Metric (VQM) computation. 56 D.5 Sampling. 57 D.6 Calibration 59 D.8 Quality parameters 87 D.9 General model 94
20、D.10 Informative references 95 D.11 Video Quality Metric (VQM) raw objective data 96 Appendix I KDDI Objective video quality assessment scheme and performance evaluation 100 I.1 Scope 100 I.2 Objective video quality assessment scheme. 100 I.3 Implementation. 103 I.4 Verification results . 105 Append
21、ix II Tektronix Inc. and Sarnoff Corporation Objective perceptual video quality measurement using a JND-based full reference technique. 108 II.1 Scope, purpose, and application . 108 II.2 References 113 II.3 Introduction 113 II.4 Algorithm overview 115 II.5 Algorithm details 119 Appendix II Attachme
22、nt 1 Bibliography . 139 Appendix II Attachment 2 Test factors, coding technologies and applications. 140 Appendix II Attachment 3 Classification of errors 142 Rec. ITU-T J.144 (03/2004) v Introduction Digital television produces new quality of service considerations, with complex relationships betwe
23、en objective parameter measurements and subjective picture quality. While objective measurements with good correlation to subjective quality assessment are desirable in order to attain optimal quality of service in the operation of cable television systems, it must be realized that objective measure
24、ments are not a direct replacement for subjective quality assessment. Subjective quality assessments are carefully designed procedures intended to determine the average opinion of human viewers to a specific set of video sequences for a given application. Results of such tests are valuable in basic
25、system design and benchmark evaluations. Subjective quality assessments for a different application with different test conditions will still provide meaningful results; however, opinion scores for the same set of video sequences are likely to have different values. Objective measurements are intend
26、ed for use in a broad set of applications producing the same results with a given set of video sequences. The choice of video sequences to use and the interpretation of the resulting objective measurements are some of the factors which vary for a specific application. Therefore, objective measuremen
27、ts and subjective quality assessment are complementary rather than interchangeable. Where subjective assessment is appropriate for research related purposes, objective measurements are required for equipment specifications and day-to-day system performance measurement and monitoring. The following t
28、erminology convention is adopted for the purpose of this Recommendation: The term “subjective assessment“ refers to the determination of the quality or impairment of programme-like pictures presented to a panel of human assessors in viewing sessions. The term “objective perceptual measurement“ refer
29、s to the measurement of the performance of a programme chain by the use of programme-like pictures and objective (instrumental) measurement methods to obtain an indication that approximates the rating that would be obtained from a subjective assessment test. The term “signal measurement“ refers to t
30、he measurement of the performance of a programme chain by the use of test signals and objective (instrumental) measurement methods. In this Recommendation, the terms “objective measurement“ and “perceptual measurement“ may be used interchangeably to mean objective perceptual measurement. There are t
31、hree basic methods to perform objective measurements: FR A method applicable when the full reference video signal is available. This is a double-ended method and is the subject of this Recommendation. RR A method applicable when only reduced video reference information is available. This is also a d
32、ouble-ended method and is the subject of a separate Recommendation (under study). NR A method applicable when no reference video signal or information is available. This is a single-ended method and the subject of a separate Recommendation (under study). The three methods have different applications
33、, and they provide different degrees of measurement accuracy, expressed in terms of correlation with subjective assessment results. Rec. ITU-T J.144 (03/2004) 1 Recommendation ITU-T J.144 Objective perceptual video quality measurement techniques for digital cable television in the presence of a full
34、 reference 1 Scope This Recommendation provides guidelines on the selection of appropriate perceptual video quality measurement equipment for use in digital cable television applications when the full reference measurement method can be used. The full reference measurement method can be used when th
35、e unimpaired reference video signal is readily available at the measurement point, as may be the case of measurements on individual equipment, or a chain in the laboratory, or in a closed environment such as a cable television head-end. The estimation methods are based on processing 8-bit digital co
36、mponent video as defined by ITU-R Rec. BT.601-51. The encoder can utilize various compression methods (e.g., MPEG, H.263, etc.). The models proposed in this Recommendation may be used to evaluate a codec (encoder/decoder combination) or a concatenation of various compression methods and memory stora
37、ge devices. While the derivation of the objective quality estimators described in this Recommendation might have considered error impairments (e.g., bit errors, dropped packets), independent testing results are not currently available to validate the use of the estimators for systems with error impa
38、irments. The validation test material did not contain channel errors. It contained coding degradations and the compression rates were 768 kbit/s-5 Mbit/s. NOTE The structure and content of this Recommendation have been organized for case of use by those familiar with the original source material; as
39、 such, the usual style of ITU-T Recommendation has not been applied. 1.1 Application This Recommendation provides video quality estimations for television video classes (TV0-TV3), and multimedia video class (MM4) as defined in Annex B/P.911. The applications for the estimation models described in th
40、is Recommendation include, but are not limited to: 1) codec evaluation, specification, and acceptance testing, consistent with the limited accuracy as described below; 2) potentially real-time, in-service quality monitoring at the source; 3) remote destination quality monitoring when a copy of the s
41、ource is available; 4) quality measurement of a storage or transmission system that utilizes video compression and decompression techniques, either a single pass or a concatenation of such techniques. 1.2 Limitations The estimation models described in this Recommendation cannot be used to replace su
42、bjective testing. Correlation values between two carefully designed and executed subjective tests (i.e., in two different laboratories) normally fall within the range 0.92 to 0.97. This Recommendation does not supply a means for quantifying potential estimation errors. Users of this Recommendation s
43、hould review the comparison of available subjective and objective results to gain an understanding of the range of video quality rating estimation errors. _ 1This does not preclude implementation of the measurement method for one-way video systems that utilize composite video input and outputs. Spec
44、ification of the conversion between composite and component domains is not part of this Recommendation. For example, SMPTE 170M specifies one method for performing this conversion for NTSC. 2 Rec. ITU-T J.144 (03/2004) The predicted performance of the estimation models is not currently validated for
45、 video systems with transmission channel error impairments. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All
46、 Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is reg
47、ularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. 2.1 Normative references ITU-R Recommendation BT.601-5 (1995), Studio encoding parameters of digital television for standard 4:3 and wide-screen 16:9
48、aspect ratios. 2.2 Informative references ITU-T Recommendation J.140 (1998), Subjective picture quality assessment for digital cable television systems. ITU-T Recommendation J.143 (2000), User requirements for objective perceptual video quality measurements in digital cable television. ITU-T Recomme
49、ndation P.910 (1996), Subjective video quality assessment methods for multimedia applications. ITU-T Tutorial (2004), Objective perceptual assessment of video quality: Full reference television. ITU-T Recommendation P.911 (1998), Subjective audiovisual quality assessment methods for multimedia applications. U. S. Standards Committee T1*Technical Report T1.TR.73-2001, Video normalization methods applicable to objective video quality metrics utilizing a full reference technique. ITU-R Recommendation BT.500-11 (2
