1、 International Telecommunication Union ITU-T P.1201.1TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Amendment 1(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 Lower resolution application area Amendment 1: New Appendix I Use of ITU-T P.1201.1 internal model parameters for diagnostic purposes Recommendation ITU-T P.1201.1 (2012) Amendment 1 ITU-T P-SERIES RECOMMENDATIONS TERMINALS AND SUBJECTIVE AND OBJECTIVE ASSESSMENT METHODS Vocab
3、ulary 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 relat
4、ed 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 Models
5、 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.1201.1 (2012)/Amd
6、.1 (12/2013) i Recommendation ITU-T P.1201.1 Parametric non-intrusive assessment of audiovisual media streaming quality Lower resolution application area Amendment 1 New Appendix I Use of ITU-T P.1201.1 internal model parameters for diagnostic purposes Summary Amendment 1 to Recommendation ITU-T P.1
7、201.1 (2012) introduces Appendix I. History Edition Recommendation Approval Study Group Unique ID*1.0 ITU-T P.1201.1 2012-10-14 12 11.1002/1000/117281.1 ITU-T P.1201.1 (2012) Amd. 1 2013-12-12 12 11.1002/1000/12110_ *To access the Recommendation, type the URL http:/handle.itu.int/ in the address fie
8、ld of your web browser, followed by the Recommendations unique ID. For example, http:/handle.itu.int/11.1002/1000/11830-en. ii Rec. ITU-T P.1201.1 (2012)/Amd.1 (12/2013) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunicatio
9、ns, 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 telecommunications
10、 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 procedure laid
11、 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 telecommunicat
12、ion 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 these manda
13、tory 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 ITU draws a
14、ttention 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 members or ot
15、hers 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 represent t
16、he 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 written permission of ITU. Rec. ITU-T P.1201.1 (2012)/Amd
17、.1 (12/2013) 1 Recommendation ITU-T P.1201.1 Parametric non-intrusive assessment of audiovisual media streaming quality Lower resolution application area Amendment 1 New Appendix I Use of ITU-T P.1201.1 internal model parameters for diagnostic purposes 1) Appendix I Introduce Appendix I at the end o
18、f the Recommendation as shown below. Appendix I Use of ITU-T P.1201.1 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.1201.1 presents a short description of which parameters of t
19、he model can be used for diagnostic purposes. The document 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 can be retrieved, and the respective model output to which it
20、 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 are only describing the internal relationship between the model in
21、ternal parameters and quality, when the output MOS of the models is low. They do not reflect relationship between video encoding parameters in general and quality. For example, the encoding complexity is not a quality problem in itself, but can explain why the MOS score drops in certain circumstance
22、s. I.2 Diagnostic use of model parameters Parameter Provided information Clause in ITU-T P.1201.1 Relationship of parameter values to quality Module dependent on this parameter videoFrameRate Video frame rate 6.1.2 Lower means worse quality Video videoCodec Video codec type 6.1.2 Video 2 Rec. ITU-T
23、P.1201.1 (2012)/Amd.1 (12/2013) Parameter Provided information Clause in ITU-T P.1201.1 Relationship of parameter values to quality Module dependent on this parameter videoResolution Video frame size 6.1.2 Lower means worse quality Video videoPLC Type of packet loss concealment used 6.1.2 Video NRE
24、Number of rebuffering events 6.1.3 Higher means worse quality Video + audiovisual ARL Average rebuffering length 6.1.3, Eq. 6-9 Higher means worse quality Video + audiovisual MREEF Multiple rebuffering events effect factor 6.1.3, Eq. 6-10 Video + audiovisual V_AIRF Average impairment rate of video f
25、rames 6.3.2, Eq. 6-33 Higher means worse quality Video V_PLEF Video packet loss event frequency 6.3.2 Higher means worse quality Video V_BR Video bit rate 6.3.2, Eq. 6-30 Lower means worse quality Video V_CCF Video content complexity factor 6.3.2, Eq. 6-32 Higher means worse quality Video V_MOSC Vid
26、eo quality due to compression 6.4.2, Eqs. 6-38, 39, 40 Lower means worse quality Range: 1 to 5 Audiovisual V_MOSP Video quality due to packet loss 6.4.2, Eqs. 6-41, 42, 43 Lower means worse quality Range: 1 to 5 Audiovisual V_MOSR Video quality due to rebuffering 6.4.2, Eqs. 6-44, 45 Lower means wor
27、se quality Range: 1 to 5 Audiovisual V_IR Impairment rate of video stream (slicing) 6.3.2, Eq. 6-34 Higher means worse quality Video audioCodec Audio codec type 6.1.1 Audio A_CR Audio bandwidth / sampling frequency 6.1.1, Eq. 6-1 Lower means worse quality Audio A_BR Audio bit rate 6.3.1 Lower means
28、worse quality Audio A_MOS Total audio quality score 6.4.1, Eqs. 6-35, 36, 37 Lower means worse quality Range: 1 to 5 Audiovisual A_MOSC Audio quality due to compression 6.4.1, Eqs. 6-36, 37 Lower means worse quality Range: 1 to 5 Audiovisual A_LFL Audio packet loss degradation parameter 6.3.1, Eq. 6
29、-27 Higher means worse quality Audio Rec. ITU-T P.1201.1 (2012)/Amd.1 (12/2013) 3 Parameter Provided information Clause in ITU-T P.1201.1 Relationship of parameter values to quality Module dependent on this parameter AV_MOSR Audio visual quality due to rebuffering 6.4.3, Eqs. 6-52, 53 Lower means wo
30、rse quality Range: 1 to 5 Audiovisual AV_MOSC Audio visual quality due to compression 6.4.3, Eq. 6-46 Lower means worse quality Range: 1 to 5 Audiovisual AV_MOSP Audio visual quality due to packet loss 6.4.3, Eqs. 6-47, 48, 49, 50, 51 Lower means worse quality Range: 1 to 5 Audiovisual AV_MOS Audio
31、visual MOS 6.4.3 Lower means worse quality Range: 1 to 5 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; the AV
32、_MOS score is dependent on outputs from the video quality estimation model, the audio quality estimation model and a number of rebuffering related parameters. By going back one step from the audiovisual quality estimation model these three areas can be investigated individually. If, for example, the
33、 video related parameters are good but the A_MOS is low, it is sufficient to follow the flow chart down to the parameters that the audio quality estimation model is using and investigate those separately. On the other hand, if the V_MOS is low, but A_MOS is high, there might be no reason to include
34、the audio parameters in the analysis. 4 Rec. ITU-T P.1201.1 (2012)/Amd.1 (12/2013) P.1201.1(12)-Amd.1(13)_FI.1videoCodecvideoFrameRatevideoPLCV_BRV_CCFV_AIRFV_IRV_PLEFV_MOSV_MOSCV_MOSPV_DPAV_ MO SAudiovisual quality estimation modelVideo quality estimation modelA_MOSA_MOSCAudio quality estimation mo
35、delNREARLMREEFaudioCodecA_BRA_LFLPrinted 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 Series F Non-telephone telecom
36、munication 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 signals Series K Protection
37、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 transmission circuits Series O Specifi
38、cations 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 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
