1、 International Telecommunication Union ITU-T G.1070TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (07/2012) SERIES G: TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS Multimedia Quality of Service and performance Generic and user-related aspects Opinion model for video-telephony applica
2、tions Recommendation ITU-T G.1070 ITU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS INTERNATIONAL TELEPHONE CONNECTIONS AND CIRCUITS G.100G.199 GENERAL CHARACTERISTICS COMMON TO ALL ANALOGUE CARRIER-TRANSMISSION SYSTEMS G.200G.299 INDIVIDUAL CHARACTERISTICS
3、OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON METALLIC LINES G.300G.399 GENERAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON RADIO-RELAY OR SATELLITE LINKS AND INTERCONNECTION WITH METALLIC LINES G.400G.449 COORDINATION OF RADIOTELEPHONY AND LINE TELEPHONY G.450G.499 TRANSMISSION ME
4、DIA AND OPTICAL SYSTEMS CHARACTERISTICS G.600G.699 DIGITAL TERMINAL EQUIPMENTS G.700G.799 DIGITAL NETWORKS G.800G.899 DIGITAL SECTIONS AND DIGITAL LINE SYSTEM G.900G.999 MULTIMEDIA QUALITY OF SERVICE AND PERFORMANCE GENERIC AND USER-RELATED ASPECTS G.1000G.1999TRANSMISSION MEDIA CHARACTERISTICS G.60
5、00G.6999 DATA OVER TRANSPORT GENERIC ASPECTS G.7000G.7999 PACKET OVER TRANSPORT ASPECTS G.8000G.8999 ACCESS NETWORKS G.9000G.9999 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T G.1070 (07/2012) i Recommendation ITU-T G.1070 Opinion model for video-telephony applic
6、ations Summary Recommendation ITU-T G.1070 proposes an algorithm that estimates videophone quality for quality of experience (QoE)/quality of service (QoS) planners. This model can be used by QoE/QoS planners to help ensure that users will be satisfied with end-to-end service quality. The model prov
7、ides estimates of multimedia quality that take interactivity into account and it allows planners to avoid under-engineering. The application of this Recommendation is limited to QoE/QoS planning. Other applications such as quality benchmarking and monitoring are outside the scope of this Recommendat
8、ion. History Edition Recommendation Approval Study Group 1.0 ITU-T G.1070 2007-04-22 12 1.1 ITU-T G.1070 (2007) Amd. 1 2009-11-12 12 2.0 ITU-T G.1070 2012-07-14 12 Keywords MOS, multimedia, opinion model, QoE, QoS, quality planning, subjective quality, video telephony. ii Rec. ITU-T G.1070 (07/2012)
9、 FOREWORD The International Telecommunication Union (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 stu
10、dying technical, operating and tariff questions and 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 gro
11、ups which, in turn, produce Recommendations on these 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
12、ISO and IEC. NOTE In this Recommendation, the expression “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 provisi
13、ons (to ensure, e.g., interoperability or applicability) 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 suc
14、h words does not suggest that compliance with the Recommendation 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 positio
15、n concerning the evidence, validity or applicability 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 not received notice of intellectual property, protecte
16、d by patents, which may be required to implement this Recommendation. 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 2013 All rights reserved. No part of t
17、his publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. Rec. ITU-T G.1070 (07/2012) iii Table of Contents Page 1 Scope 1 2 References. 1 3 Definitions 2 3.1 Terms defined elsewhere 2 3.2 Terms defined in this Recommendation . 3 4 Abbreviations and acr
18、onyms 4 5 Conventions 4 6 Application . 5 7 Framework 5 8 Model assumptions . 7 8.1 Speech-related assumptions 7 8.2 Video-related assumptions . 8 8.3 Task-related assumptions . 8 9 Model inputs . 8 9.1 Speech quality parameters 8 9.2 Video quality parameters 9 10 Model outputs . 10 11 Model descrip
19、tion . 10 11.1 Speech quality estimation function for narrowband speech . 10 11.2 Speech quality estimation function for wideband speech 11 11.3 Video quality estimation function 12 11.4 Multimedia quality integration function . 13 12 Accuracy of model 14 Annex A Methodology for deriving the coeffic
20、ients in the video quality estimation function with respect to coding and packet-loss degradation . 16 A.1 Methodology for deriving coefficients v1, v2, ., and v7 16 A.2 Methodology for deriving coefficients v8, v9, , and v12 . 17 Appendix I Coefficients in the video quality estimation function with
21、 respect to coding and packet-loss degradation 19 Appendix II Coefficients in the multimedia quality integration function . 21 Bibliography. 22 Rec. ITU-T G.1070 (07/2012) 1 Recommendation ITU-T G.1070 Opinion model for video-telephony applications 1 Scope This Recommendation describes a computation
22、al model for point-to-point interactive videophone applications over IP networks that is useful as a QoE/QoS planning tool for assessing the combined effects of variations in several video and speech parameters that affect the quality of experience (QoE). This model can be used by QoE/QoS planners t
23、o help ensure that users will be satisfied with end-to-end service quality. Actually they want to avoid under-engineering. Network, application and terminal quality parameters of high importance to QoE/QoS planners are incorporated into this model. The model provided in this Recommendation needs to
24、be a flexible tool capable of providing feedback on individual qualities as well as overall quality. This Recommendation is very different from ITU-T J.148 in terms of input parameters. In this Recommendation, multimedia quality is calculated by using network, application and terminal equipment para
25、meters, whereas in ITU-T J.148, the calculation is done by using speech and video signals. This Recommendation assumes videophone applications using dedicated videophone terminals, desktop PCs, laptop PCs, PDAs and mobile phones. The speech bandwidth is limited to the telephone band (300-3400 Hz). T
26、he application of this Recommendation is limited to QoE/QoS planning. Other applications such as quality benchmarking and monitoring are outside the scope of this Recommendation. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this
27、 text, constitute provisions of this Recommendation. At the time of publication, the editions 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 editi
28、on of the Recommendations and other references listed below. A list of the currently valid 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 G.107 Recommendation ITU-
29、T G.107 (2005), The E-model: a computational model for use in transmission planning. ITU-T G.107.1 Recommendation ITU-T G.107.1 (2011), Wideband E-model. ITU-T G.113 Recommendation ITU-T G.113 (2001), Transmission impairments due to speech processing. ITU-T G.122 Recommendation ITU-T G.122 (1993), I
30、nfluence of national systems on stability and talker echo in international connections. ITU-T G.711 Recommendation ITU-T G.711 (1988), Pulse code modulation (PCM) of voice frequencies. ITU-T J.144 Recommendation ITU-T J.144 (2004), Objective perceptual video quality measurement techniques for digita
31、l cable television in the presence of a full reference. 2 Rec. ITU-T G.1070 (07/2012) ITU-T J.148 Recommendation ITU-T J.148 (2003), Requirements for an objective perceptual multimedia quality model. ITU-T P.79 Recommendation ITU-T P.79 (1980), Calculation of loudness ratings ITU-T P.561 Recommendat
32、ion ITU-T P.561 (2002), In-service non-intrusive measurement device Voice service measurements. ITU-T P.562 Recommendation ITU-T P.562 (2004), Analysis and interpretation of INMD voice-service measurements. ITU-T P.563 Recommendation ITU-T P.563 (2004), Single-ended method for objective speech quali
33、ty assessment in narrow-band telephony applications. ITU-T P.564 Recommendation ITU-T P.564 (2007), Conformance testing for voice over IP transmission quality assessment models. ITU-T P.800 Recommendation ITU-T P.800 (1996), Methods for subjective determination of transmission quality. ITU-T P.833 R
34、ecommendation ITU-T P.833 (2001), Methodology for derivation of equipment impairment factors from subjective listening-only tests. ITU-T P.834 Recommendation ITU-T P.834 (2002), Methodology for the derivation of equipment impairment factors from instrumental models. ITU-T P.862 Recommendation ITU-T
35、P.862 (2001), Perceptual evaluation of speech quality (PESQ): An objective method for end-to-end speech quality assessment of narrow-band telephone networks and speech codecs. ITU-T P.862.1 Recommendation ITU-T P.862.1 (2003), Mapping function for transforming P.862 raw result scores to MOS-LQO. ITU
36、-T P.862.2 Recommendation ITU-T P.862.2 (2005), Wideband extension to Recommendation P.862 for the assessment of wideband telephone networks and speech codecs. ITU-T P.910 Recommendation ITU-T P.910 (1999), Subjective video quality assessment methods for multimedia applications. ITU-T P.911 Recommen
37、dation ITU-T P.911 (1998), Subjective audiovisual quality assessment methods for multimedia applications. ITU-T P.920 Recommendation ITU-T P.920 (2000), Interactive test methods for audiovisual communications. ITU-R BS.1387-1 Recommendation ITU-R BS.1387-1 (2001), Method for objective measurements o
38、f perceived audio quality. 3 Definitions 3.1 Terms defined elsewhere None. Rec. ITU-T G.1070 (07/2012) 3 3.2 Terms defined in this Recommendation This Recommendation defines the following terms shown in Table 1: Table 1 List of definitions Name Description Unit AD Absolute audio-visual delay bnVideo
39、 bit rate (n = 1, 2, , N) kbit/s BplSSpeech packet-loss robustness BrVVideo bit rate kbit/s DbnfmDegree of video quality robustness against packet loss (n = 1, 2, , N, m = 1, 2, , M) DFrVDegree of video quality robustness due to frame rate reduction DnDegree of video quality robustness due to frame
40、rate reduction (n = 1, 2, , N) DPplVDegree of video quality robustness against packet loss fmFrame rate (m = 1, 2, , M) fps FrVVideo frame rate fps IcodingObjective measurement of basic video quality accounting for coding distortion Idd Degradation caused by pure delay in Recommendation ITU-T G.107
41、Idd,WB Degradation caused by pure delay in Recommendation ITU-T G.107.1 Idte Degradation caused by talker echo in a narrowband context Idte,WB Degradation caused by talker echo in a wideband context Ie-eff Degradation caused by speech coding and packet loss in a narrowband context Ie-eff,WB Degradat
42、ion caused by speech coding and packet loss in a wideband context IeSSpeech coding distortion in a narrowband context IeS,WB Speech coding distortion in a wideband context InObjective measurement of maximum video quality at each bit rate (n = 1, 2, , N) IOfrObjective measurement of maximum video qua
43、lity at each bit rate MMqObjective measurement of multimedia quality accounting for the influence of speech and video quality and speech and video delay MMSVAudio-visual quality MMTAudio-visual delay impairment factor MS Audio-visual media synchronization Ofr Optimal frame rate that maximizes video
44、quality at each bit rate OnOptimal frame rate (n = 1, 2, , N) PplSSpeech packet-loss rate % PplVVideo packet-loss rate % Q Speech quality index R Transmission rating factor SqObjective measurement of speech quality 4 Rec. ITU-T G.1070 (07/2012) Table 1 List of definitions Name Description Unit Sq(Vq
45、) Objective measurement of speech quality accounting for influence of video quality TELR Talker echo loudness rating in a narrowband context dB TELR,WB Talker echo loudness rating in a wideband context dB TSSpeech delay ms TVVideo delay ms VqObjective measurement of video quality Vq(Sq) Objective me
46、asurement of video quality accounting for influence of speech quality VqsSubjective video quality Vqs(bn, fm) Subjective video quality under conditions of bnand fm 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: ACR Absolute Category Rating AEC Acousti
47、c Echo Canceller CIF Common Intermediate Format (352 288 pixels) CT Codec Type ERL Echo Return Loss KFI Key Frame Interval LSA Least Square Approximation MOS Mean Opinion Score QCIF Quarter CIF (176 144 pixels) QQVGA Quarter Quarter VGA (160 120 pixels) QVGA Quarter Video Graphics Array (320 240 pix
48、els) RLR Receiving Loudness Rating SLR Sending Loudness Rating VDS Video Display Size VF Video Format VGA Video Graphics Array (640 480 pixels) 5 Conventions In this Recommendation, “subjective quality“ refers to the mean opinion score (MOS) obtained in absolute category rating (ACR) tests as define
49、d in ITU-T P.800, ITU-T P.910, ITU-T P.911 and ITU-T P.920, depending on the media under evaluation and evaluation context such as one-way listening/viewing and two-way interactive communication. Rec. ITU-T G.1070 (07/2012) 5 6 Application The application of this Recommendation is limited to QoE/QoS planning. Other applications such as quality benchmarking and monitoring are outside the scope of this Recommendati
