1、 International Telecommunication Union ITU-T P.1201.2TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Amendment 2(12/2013) SERIES P: TERMINALS AND SUBJECTIVE AND OBJECTIVE ASSESSMENT METHODS Models and tools for quality assessment of streamed media Parametric non-intrusive assessment of audiovisual m
2、edia streaming quality Higher resolution application area Amendment 2: New Appendix I Use of ITU-T P.1201.2 internal model parameters for diagnostic purposes Recommendation ITU-T P.1201.2 (2012) Amendment 2 ITU-T P-SERIES RECOMMENDATIONS TERMINALS AND SUBJECTIVE AND OBJECTIVE ASSESSMENT METHODS Voca
3、bulary and effects of transmission parameters on customer opinion of transmission quality Series P.10 Voice terminal characteristics Series P.30 P.300 Reference systems Series P.40 Objective measuring apparatus Series P.50 P.500 Objective electro-acoustical measurements Series P.60 Measurements rela
4、ted to speech loudness Series P.70 Methods for objective and subjective assessment of speech quality Series P.80 P.800 Audiovisual quality in multimedia services Series P.900 Transmission performance and QoS aspects of IP end-points Series P.1000 Communications involving vehicles Series P.1100 Model
5、s and tools for quality assessment of streamed media Series P.1200Telemeeting assessment Series P.1300 Statistical analysis, evaluation and reporting guidelines of quality measurements Series P.1400 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T P.1201.2 (2012)/Am
6、d.2 (12/2013) i Recommendation ITU-T P.1201.2 Parametric non-intrusive assessment of audiovisual media streaming quality Higher resolution application area Amendment 2 New Appendix I Use of ITU-T P.1201.2 internal model parameters for diagnostic purposes Summary Amendment 2 to Recommendation ITU-T P
7、.1201.2 (2012) introduces Appendix I. History Edition Recommendation Approval Study Group Unique ID11.0 ITU-T P.1201.2 2012-10-14 12 11.1002/1000/11729-en1.1 ITU-T P.1201.2 (2012) Amd. 1 2013-05-14 12 11.1002/1000/11936-en1.2 ITU-T P.1201.2 (2012) Amd. 2 2013-12-12 12 11.1002/1000/12111-en_ 1To acce
8、ss the Recommendation, type into the address line on the web browser the URL http:/handle.itu.int/ followed by the unique ID, for example http:/handle.itu.int/11.1002/1000/11830-en. ii Rec. ITU-T P.1201.2 (2012)/Amd.2 (12/2013) FOREWORD The International Telecommunication Union (ITU) is the United N
9、ations 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 and issuing Recommendatio
10、ns 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 these topics. The approval
11、 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 expression “Administration“
12、 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 applicability) and compliance w
13、ith 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 Recommendation is requi
14、red 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 applicability of claimed Intellect
15、ual 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 Recommendation. However
16、, 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 2014 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior
17、 written permission of ITU. Rec. ITU-T P.1201.2 (2012)/Amd.2 (12/2013) 1 Recommendation ITU-T P.1201.2 Parametric non-intrusive assessment of audiovisual media streaming quality Higher resolution application area Amendment 2 New Appendix I Use of ITU-T P.1201.2 internal model parameters for diagnost
18、ic purposes 1) Appendix I Introduce Appendix I at the end of the Recommendation as shown below. Appendix I Use of ITU-T P.1201.2 internal model parameters for diagnostic purposes (This appendix does not form an integral part of this Recommendation.) I.1 Introduction The present appendix to ITU-T P.1
19、201.2 presents a short description of which parameters of the model can be used for diagnostic purposes. The appendix is centred on a table that indicates the parameters and the respective clauses in which these can be found. Further, it contains information about the level at which the parameter ca
20、n be retrieved, and the respective model output to which it is related. Note that the highlighted parameters are at the highest level, that is, they should be used as the starting point for identifying why quality may be low. Note also that the relationship between the parameters and quality only de
21、scribe the internal relationship between the model internal parameters and quality when the output MOS of the models is low. They do not reflect the relationship between video encoding parameters in general and quality. For example, the encoding complexity is not a quality problem in itself, but can
22、 explain why the MOS score drops in certain circumstances. I.2 Diagnostic use of model parameters Parameter Provided information Clause in ITU-T P.1201.2 Values that might be cause for problems Module dependent on this parameter GlobalInfo.Video. FrameRate Video frame rate 6.1 Lower means worse qual
23、ity Video GlobalInfo.Video. Resolution Video resolution 6.1 Video GlobalInfo.Video. isInterlaced 0: progressive, 1: interlaced 6.1 Video 2 Rec. ITU-T P.1201.2 (2012)/Amd.2 (12/2013) Parameter Provided information Clause in ITU-T P.1201.2 Values that might be cause for problems Module dependent on th
24、is parameter GlobalInfo.Video. Codec Video codec 6.1 Video GlobalInfo.Video. ConcealmentType Slicing or freezing packet loss concealment type 6.1 Video GlobalInfo.Video. NumSlices Number of slices per frame 6.1 Video VideoSequenceData. BitPerPixel Number of encoded bits per pixel 6.3 Lower means wor
25、se quality Video VideoSequenceData. ContentComplexity Content encoding complexity 6.3 Higher means worse quality Video VideoSequenceData. FreezingRatio Ratio of frozen video frames to total number of video frames 6.3 Higher means worse quality Video VideoSequenceData. LossMagnitude Impact of losses
26、due to slicing packet loss concealment 6.3 Higher means worse quality Video QcodV Estimated video quality due to video compression artefacts 6.4.2 Higher means worse quality. Range: 0 to 100 Audiovisual QtraV Estimated video quality due to video transmission degradations 6.4.2 Higher means worse qua
27、lity. Range: 0 to 100 Audiovisual MOSV Estimated Video MOS score 6.4.2 Lower means worse quality. Range: 1 to 5 Audiovisual GlobalInfo.Audio. Codec Audio codec 6.1 Audio GlobalInfo.Audio. Bitrate Encoded audio bitrate 6.1 Lower means worse quality (see ITU-T P.1201.2 for codec-specific ranges) Audio
28、 GlobalInfo.Audio. SampleRate Audio sample rate 6.1 Lower means worse quality Audio GlobalInfo.Audio. FrameLength Audio frame length in samples 6.1 Audio GlobalInfo.Audio. FrameDuration Audio frame duration (in sec.) 6.1 Audio AudioSequenceData. Frameloss Audio frame loss amount 6.3.2 Higher means w
29、orse quality Audio AudioSequenceData. Burstiness Distribution of lost audio frames 6.3.2 Higher means worse quality Audio Rec. ITU-T P.1201.2 (2012)/Amd.2 (12/2013) 3 Parameter Provided information Clause in ITU-T P.1201.2 Values that might be cause for problems Module dependent on this parameter Qc
30、odA Estimated audio quality for audio compression artefacts 6.4.1 Higher means worse quality Audiovisual QtraA Estimated audio quality due to audio transmission artefacts 6.4.1 Higher means worse quality Audiovisual MOSA Estimated Audio MOS score 6.4.1 Lower means worse quality Audiovisual MOS-AV Es
31、timated Audiovisual MOS score 6.4.3 Lower means worse quality Audiovisual The flowchart below represents the information flow for the parameters used to calculate the audiovisual MOS estimate. This can be used to do fault localization by following the arrows in the opposite direction, for example; t
32、he MOS-AV score is dependent on outputs from the video quality estimation model and from the audio quality estimation model. By going back one step from the audiovisual quality estimation model, the cause for bad audiovisual quality can be understood. In particular, it can be analysed whether the ba
33、d quality is due to bad video compression quality, audio compression quality, video transmission quality or audio transmission quality. If, for example, the video quality MOSV is high but the audio quality MOSA is low, it is sufficient to follow the flow chart down to the parameters that the audio q
34、uality estimation model is using and investigate those separately. On the other hand, if MOSV is low, but MOSA is high, there might be no reason to include the audio parameters in the analysis. 4 Rec. ITU-T P.1201.2 (2012)/Amd.2 (12/2013) AV_MOS Audiovisual quality estimation model Video quality est
35、imation model Audio quality estimation model MOSV QcodV QtraV MOSA QcodA QtraA GlobalInfo.Video .FrameRate .Resolution .isInterlaced .Codec .ConcealmentType .NumSlices GlobalInfo.Audio .Codec .Bitrate .SampleRate .FrameLength .FrameDuration AudioSequenceData .Frameless .Burstiness VideoSequenceData
36、.BitPerPixel .ContentComplexity .FreezingRatio .LossMagnitude Printed in Switzerland Geneva, 2014 SERIES OF ITU-T RECOMMENDATIONS Series A Organization of the work of ITU-T Series D General tariff principles Series E Overall network operation, telephone service, service operation and human factors S
37、eries F Non-telephone telecommunication services Series G Transmission systems and media, digital systems and networks Series H Audiovisual and multimedia systems Series I Integrated services digital network Series J Cable networks and transmission of television, sound programme and other multimedia
38、 signals Series K Protection against interference Series L Construction, installation and protection of cables and other elements of outside plant Series M Telecommunication management, including TMN and network maintenance Series N Maintenance: international sound programme and television transmiss
39、ion circuits Series O Specifications of measuring equipment Series P Terminals and subjective and objective assessment methods Series Q Switching and signalling Series R Telegraph transmission Series S Telegraph services terminal equipment Series T Terminals for telematic services Series U Telegraph
40、 switching Series V Data communication over the telephone network Series X Data networks, open system communications and security Series Y Global information infrastructure, Internet protocol aspects and next-generation networks Series Z Languages and general software aspects for telecommunication systems
