1、 International Telecommunication Union ITU-T J.244TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (04/2008) SERIES J: CABLE NETWORKS AND TRANSMISSION OF TELEVISION, SOUND PROGRAMME AND OTHER MULTIMEDIA SIGNALS Measurement of the quality of service Full reference and reduced reference calibration met
2、hods for video transmission systems with constant misalignment of spatial and temporal domains with constant gain and offset Recommendation ITU-T J.244 Rec. ITU-T J.244 (04/2008) i Recommendation ITU-T J.244 Full reference and reduced reference calibration methods for video transmission systems with
3、 constant misalignment of spatial and temporal domains with constant gain and offset Summary Recommendation ITU-T J.244 specifies full reference (FR) and reduced reference (RR) calibration methods which report alignment shifts in both space and time of processed (e.g., compressed, transmitted, and d
4、ecompressed) video sequences with respect to corresponding source video sequences. The methods also compute gain and offset of processed video sequences. The methods require that spatial and temporal shifts must be constant. Furthermore, the gain and offset must be constant. The methods in this Reco
5、mmendation are applicable to: reporting shifts that can be used to register source and processed video sequences in space and time; reporting gains, and offsets of video levels that can be used to calibrate processed video sequences with respect to the source. Intended applications for these methods
6、 include, but are not limited to, assessing the operational readiness of video transmission systems that contain compression/transmission/decompression components, obtaining calibration estimates for correcting processed video sequences before measuring subjective or objective picture quality, and v
7、erifying that video transmission systems meet specified calibration requirements. Source Recommendation ITU-T J.244 was approved on 6 April 2008 by ITU-T Study Group 9 (2005-2008) under Recommendation ITU-T A.8 procedure. ii Rec. ITU-T J.244 (04/2008) FOREWORD The International Telecommunication Uni
8、on (ITU) is the United Nations specialized agency in the field 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 a
9、nd issuing Recommendations on them with a view to standardizing 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 th
10、ese topics. The approval of ITU-T Recommendations is covered 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 exp
11、ression “Administration“ is used for conciseness to indicate 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 applicabi
12、lity) and compliance with the Recommendation is achieved when 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 R
13、ecommendation is required of any party. INTELLECTUAL PROPERTY 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 applicabilit
14、y of claimed Intellectual Property Rights, whether asserted 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 R
15、ecommendation. However, implementers are cautioned that this 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 whatsoe
16、ver, without the prior written permission of ITU. Rec. ITU-T J.244 (04/2008) iii CONTENTS Page 1 Scope 1 1.1 Applications 1 1.2 Limitations 2 2 References. 2 2.1 Normative references 2 2.2 Informative references 2 3 Abbreviations 2 4 Summary of validation results 3 5 Description of the calibration m
17、ethods. 5 Annex A Institute for Telecommunication Sciences, National Telecommunications and Information Administration, U.S. Department of Commerce Reduced Reference Video Calibration Algorithms 6 A.1 Introduction 6 A.2 Temporal registration algorithm. 6 A.3 Spatial registration algorithm . 14 A.4 V
18、alid region algorithm . 26 A.5 Luminance gain and offset algorithm. 30 A.6 Combining algorithms and applying corrections . 33 A.7 References 34 Annex B Yonsei University A calibration method for constant misalignment of spatial and temporal domains with constant gain and offset 35 B.1 Introduction 3
19、5 B.2 Spatial and temporal registration 35 B.3 Gain and offset estimation 36 B.4 Refinement . 38 Appendix I Example Validation Testplan for Calibration Methods. 39 I.1 Introduction 39 I.2 Example Calibration test plan (no variable temporal misalignment) . 39 I.3 Validation process 40 I.4 Generation
20、of Processed Video Sequences (PVSs) 40 I.5 Evaluation metrics 41 I.6 Additional information . 41 I.7 Future test plans (variable temporal misalignment for multimedia applications) 41 Appendix II Test Plan 1 (Rec. 601 only Jun 2, 2007) 42 II.1 Calibration test plan 1 (no variable temporal misalignmen
21、t) . 42 II.2 Validation process 42 II.3 Generation of Processed Video Sequences (PVSs) 42 iv Rec. ITU-T J.244 (04/2008) Page II.4 Evaluation metrics 43 Appendix III Evaluation Metrics 44 III.1 Introduction 44 III.2 Experimental results of 1190 PVSs for each video format. 44 III.3 Experimental result
22、s after removing erroneous video sequences. 47 III.4 Experimental results per HRC after removing erroneous video sequences . 50 Rec. ITU-T J.244 (04/2008) v Introduction Calibration techniques described in this Recommendation may be used for various purposes. Some of these include the verification o
23、f system setup, maintenance of delivery systems, and pre-processing for some objective video quality assessment techniques. There has been a great interest in objective models which automatically measure video quality. For some objective quality assessment methods, the source and processed (e.g., co
24、mpressed, transmitted, and decompressed) video sequences need to be registered. It is noted that some application or service scenarios may introduce spatio-temporal misalignment between processed and source video sequences. In the case where such spatio-temporal alignment problems occur, the predict
25、ion accuracy of some objective quality assessment models can be reduced. Typically, for full reference and some reduced reference objective quality assessment models, it is important that the processed and reference pictures are properly aligned. For some objective methods, alignment can be an integ
26、ral part of the model. In such models there is no need for an external alignment method. For objective models that do not include inherent alignment, there may be the need for a separate picture alignment procedure that can be performed before parameter values are derived. Intended applications for
27、these methods include, but are not limited to, assessing the operational readiness of video transmission systems that contain compression/transmission/decompression components, obtaining calibration estimates for correcting processed video sequences before measuring subjective or objective picture q
28、uality, and verifying that video transmission systems meet specified calibration requirements. Rec. ITU-T J.244 (04/2008) 1 Recommendation ITU-T J.244 Full reference and reduced reference calibration methods for video transmission systems with constant misalignment of spatial and temporal domains wi
29、th constant gain and offset 1 Scope This Recommendation specifies calibration methods which report alignment shifts in both space and time of processed (e.g., compressed, transmitted, and decompressed) video sequences with respect to corresponding source video sequences. The methods also compute gai
30、n and offset of processed video sequences. The methods require that spatial and temporal shifts must be constant. Furthermore, the gain and offset must be constant. The methods in this Recommendation are applicable to: reporting shifts that can be used to register source and processed video sequence
31、s in space and time; reporting gains, and offsets of video levels that can be used to calibrate processed video sequences with respect to the source. These methods can be used to report calibration differences between the source and processed video sequences. These values may be used to repair proce
32、ssed video sequences. Table 1 summarizes the required bandwidth and Table 2 shows the ranges of spatial and temporal shifts for which the methods in this Recommendation were tested. Table 1 Allowed bandwidth Available bandwidth for registration ITU-R 601(interlaced) Unlimited 56 kbit/s 10 kbit/s 5 k
33、bit/s 1 kbit/s 0.5 kbit/s VGA (progressive) Unlimited 56 kbit/s 10 kbit/s 5 kbit/s 1 kbit/s 0.5 kbit/s CIF (progressive) Unlimited 56 kbit/s 10 kbit/s 5 kbit/s 1 kbit/s 0.5 kbit/s QCIF (progressive) Unlimited 56 kbit/s 10 kbit/s 5 kbit/s 1 kbit/s 0.5 kbit/s HD (interlaced) Unlimited 56 kbit/s 10 kbi
34、t/s 5 kbit/s 1 kbit/s 0.5 kbit/s HD (progressive) Unlimited 56 kbit/s 10 kbit/s 5 kbit/s 1 kbit/s 0.5 kbit/s Table 2 Expected conditions Source video length 8 seconds Maximum spatial shift (vertical and horizontal) 20 pixels Maximum temporal shift 1 second Gain (Y-component) 10% Offset (Y-component)
35、 10 grey levels 1.1 Applications Intended applications for these methods include, but are not limited to, assessing the operational readiness of video transmission systems that contain compression/transmission/decompression components, obtaining calibration estimates for correcting processed video s
36、equences before measuring subjective or objective picture quality, and verifying that video transmission systems meet specified calibration requirements. 2 Rec. ITU-T J.244 (04/2008) 1.2 Limitations The methods presented in this Recommendation require access to both source and processed video sequen
37、ces. The spatial and temporal shifts must remain constant for the entire processed video sequences. Furthermore, the gain and offset must be fixed. NOTE The structure and content of this Recommendation have been organized for ease of use by those familiar with the original source material; as such,
38、the usual style of ITU-T recommendations has not been applied. 2 References 2.1 Normative 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 editio
39、ns indicated were valid. All 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
40、ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. ITU-T J.144 Recommendation ITU-T J.144 (2004), Objective perceptual video quality measurement techniques for digital cable
41、 television in the presence of a full reference. ITU-R BT.1683 Recommendation ITU-R BT.1683 (2004), Objective perceptual video quality measurement techniques for standard definition digital broadcast television in the presence of a full reference. 2.2 Informative references None. 3 Abbreviations Thi
42、s Recommendation uses the following abbreviations: CODEC COder-DECoder FR Full Reference GOP Group Of Pictures HRC Hypothetical Reference Circuit IRT Institut Rundfunk Technische (Germany) MOS Mean Opinion Score MPEG Moving Picture Experts Group NR No (or Zero) Reference NTSC National Television Sta
43、ndard Committee (60 Hz TV) PAL Phase Alternating Line standard (50 Hz TV) RR Reduced Reference SMPTE Society of Motion Picture and Television Engineers SRC Source Reference Channel or Circuit Rec. ITU-T J.244 (04/2008) 3 SSCQE Single Stimulus Continuous Quality Evaluation VQEG Video Quality Experts
44、Group 4 Summary of validation results In accordance with the validation testplan for calibration methods in Appendices I and II, a total of 1190 test video sequences (525 video format) are generated from the VQEG Phase I data for various test conditions (different source video sequences and HRCs). T
45、he evaluation metrics of the testplan are provided in Appendix III. However, it was found that some of the original VQEG Phase I data were not correctly calibrated and some video sequences include still scene. Consequently, these incorrectly-calibrated and still-scene video sequences will inevitably
46、 introduce additional errors which have nothing to do with the calibration methods. When these problematic video sequences are removed, there are 973 PVSs for the 525 video format and 812 PVS for the 625 video format. Furthermore, since the test video sequences are stored in the integer format, they
47、 inherently include round-up errors which no model can predict. With those round-up errors, it would be meaningless to present the percentiles of correct results with no error in any aspect. Tables 3-6 show the mean values of the five errors and error statistics for the 525 video format after removi
48、ng the problematic video sequences. Tables 7-8 show the mean values of the five errors and error statistics for the 625 video format after removing the problematic video sequences. Appendix III presents additional error statistics. Table 3 Mean values of the five errors (525 format, 973 PVSs) Mean (
49、Ex) Mean (Ey) Mean (Et) Mean (Eg) Mean (Eo) NTIA 25k 0 0 0.015 0.005 1.111 Yonsei unlimited 0 0.00084 0.006723 0.005649 0.621204 Yonsei 56k 0 0.007563 0 0.005799 0.62936 Yonsei 10k 0.00168 0.00168 0.014286 0.006 0.624177 Yonsei 5k 0.00084 0.007563 0.002521 0.006184 0.590344 Yonsei 1k 0.002521 0.00252 0.021008 0.014237 0.56031 Yonsei 0.5k 0.00924 0.010084 0.058824 0.01666 0.68251 Table 4 Error statistics of mean values (525 format, 973 PVSs) Percentile Ex+Ey0 Ex+Ey1 Ex+Ey+Et=0 Ex+Ey+Et1 Ex+Ey+Et2 NTIA 25k 100 100 98.739 99.748 100 Yonsei
