1、 I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n ITU-T P.1203 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (10/2017) SERIES P: TELEPHONE TRANSMISSION QUALITY, TELEPHONE INSTALLATIONS, LOCAL LINE NETWORKS Models and tools for quality assessment of streamed media Parametric bi
2、tstream-based quality assessment of progressive download and adaptive audiovisual streaming services over reliable transport Recommendation ITU-T P.1203 ITU-T P-SERIES RECOMMENDATIONS TELEPHONE TRANSMISSION QUALITY, TELEPHONE INSTALLATIONS, LOCAL LINE NETWORKS Vocabulary and effects of transmission
3、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 related to speech loudness Series P.70
4、Methods for objective and subjective assessment of speech quality Series P.80 Methods for objective and subjective assessment of speech and video quality Series P.800 Audiovisual quality in multimedia services Series P.900 Transmission performance and QoS aspects of IP end-points Series P.1000 Commu
5、nications involving vehicles Series P.1100 Models and tools for quality assessment of streamed media Series P.1200 Telemeeting assessment Series P.1300 Statistical analysis, evaluation and reporting guidelines of quality measurements Series P.1400 Methods for objective and subjective assessment of q
6、uality of services other than speech and video Series P.1500 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T P.1203 (10/2017) i Recommendation ITU-T P.1203 Parametric bitstream-based quality assessment of progressive download and adaptive audiovisual streaming serv
7、ices over reliable transport Summary Recommendation ITU-T P.1203 provides the introductory document for a set of documents that describe model algorithms for monitoring the integral media session quality for TCP-type video streaming. The models comprise modules for short-term audio- and video-qualit
8、y estimation. The per-one-second outputs of these short-term modules are integrated into estimates of audiovisual quality and, together with information about initial loading delay and media playout stalling events, further integrated into the final model output, the estimate of integral quality. Th
9、e respective ITU-T work item has formerly been referred to as P.NATS (Parametric non-intrusive assessment of TCP-based multimedia streaming quality). The structure of the set of recommendations reflects the different functionality of modules described in each document: ITU-T P.1203: Introductory doc
10、ument (this Recommendation) ITU-T P.1203.1: Video quality estimation module (short-term, providing per-one-second output information) ITU-T P.1203.2: Audio quality estimation module (short-term, providing per-one-second output information) ITU-T P.1203.3: Audiovisual integration and integration of f
11、inal score, reflecting remembered quality for viewing sessions between 30 s and 5 min duration The input used by the models consists of information obtained by prior stream inspection. Four different levels of inspection are included, resulting in models of different complexity both of the input inf
12、ormation and the model algorithms, which are called “modes of operation“ in the following: Mode 0: Information obtained from meta-information available during progressive download or adaptive streaming, for example from manifest files used in DASH, about codec and bitrate, and initial loading delay
13、and stalling. Mode 1: All information from Mode 0, with additional video and audio frame information based on packet header inspection Mode 2: All information from Mode 1, and up to 2% (in Bytes) of the overall media stream information based on deep packet inspection and partial bitstream parsing Mo
14、de 3: All information from Mode 1, and complete media stream information based on bitstream parsing The ITU-T P.1203-series of Recommendations addresses two application areas, which are respectively indicated in the module-related Recommendations ITU-T P.1203.1, ITU-T P.1203.2, ITU-T P.1203.3: Large
15、-screen presentation as with fixed-network video streaming Mobile streaming on handheld devices such as smartphones The ITU-T P.1203 module algorithms are no-reference, bitstream-based models. ii Rec. ITU-T P.1203 (10/2017) History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T P.1
16、203 2016-11-29 5 11.1002/1000/13158 1.1 ITU-T P.1203 (2016) Amd. 1 2017-01-19 12 11.1002/1000/13166 2.0 ITU-T P.1203 2017-10-29 12 11.1002/1000/13399 Keywords Adaptive streaming, audio, audiovisual, IPTV, mean opinion score (MOS), mobile video, mobile TV, monitoring, multimedia, progressive download
17、, QoE, TV, video. _ * To access the Recommendation, type the URL http:/handle.itu.int/ in the address field of your web browser, followed by the Recommendations unique ID. For example, http:/handle.itu.int/11.1002/1000/ 11830-en. Rec. ITU-T P.1203 (10/2017) iii FOREWORD The International Telecommuni
18、cation 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 studying technical, operating and tariff q
19、uestions 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 groups which, in turn, produce Recommendat
20、ions 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 ISO and IEC. NOTE In this Recommendatio
21、n, 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 provisions (to ensure, e.g., interoperability
22、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 such words does not suggest that complianc
23、e with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTSITU 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 a
24、pplicability 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 imple
25、ment 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 2017 All rights reserved. No part of this publication may be reproduced, by any me
26、ans whatsoever, without the prior written permission of ITU. iv Rec. ITU-T P.1203 (10/2017) Table of Contents Page 1 Scope . 1 2 References . 2 3 Definitions 2 3.1 Terms defined elsewhere 2 3.2 Terms defined in this Recommendation . 3 4 Abbreviations and acronyms 3 5 Conventions 4 6 Areas of applica
27、tion 4 6.1 Application range for the models . 5 6.2 Modes of operation . 6 7 Building blocks . 6 7.1 Model input interfaces 7 7.2 Specification of Inputs I.11, I.13 and I.14 7 7.3 Stalling 9 7.4 Measurement window specification . 9 7.5 Model output information . 12 8 Overview of databases used for m
28、odel development . 12 9 Description of the ITU-T P.1203 model algorithms . 13 Appendix I Performance figures . 14 Rec. ITU-T P.1203 (10/2017) 1 Recommendation ITU-T P.1203 Parametric bitstream-based quality assessment of progressive download and adaptive audiovisual streaming services over reliable
29、transport 1 Scope This Recommendation describes a set of objective parametric quality assessment modules that together can be used to form a complete model to predict the impact of audio and video media encodings and observed IP network impairments on quality experienced by the end-user in multimedi
30、a streaming applications. The addressed streaming techniques comprise progressive download as well as adaptive streaming, for both mobile and fixed network streaming applications. Four modes are defined to cover a range of use-cases, from monitoring streams where the video payload is fully encrypted
31、 through to unencrypted streams, and where there are no limitations on processing power so that deep packet inspection is possible. The model described is restricted to information provided to it by an appropriate bit stream analysis module or set of modules. The model described here is applicable t
32、o progressive download and adaptive streaming, where the quality experienced by the end user is affected by audio-coding and/or video degradations due to coding, spatial re-scaling or variations in video frame rates, as well as delivery degradations due to initial loading delay, stalling (which are
33、both caused by rebuffering at the client), and media adaptations. Here, a “media adaptation“ refers to events where the player switches video playback between a known set of media quality levels while adapting to network conditions. Each of the quality levels typically differs in a significant video
34、 and/or audio (and thus audiovisual) quality change. These quality changes are most readily observed by changes in bitrate, resolution, frame rate, and similar attributes. The model predicts a mean opinion score (MOS) on a 5-point absolute category rating (ACR) scale (see ITU-T P.910) as a global mu
35、lti-media MOS score (as defined in ITU-T P.911, for instance). In addition, the well-defined modules provide several diagnostic outputs. The primary applications for this model are monitoring of transmission quality for operations and maintenance purposes. The ITU-T P.1203 model for adaptive- and pr
36、ogressive-download-type media streaming may be deployed both in end-point locations and at mid-network monitoring points. Note, however, that the present Recommendation only describes the model that maps input parameters obtained from a probe located at a specific point in the network or in the clie
37、nt to the global multimedia MOS-scores and related quality diagnostic indicators, as described above. The model associated with this Recommendation cannot provide a comprehensive evaluation of transmission quality as perceived by an individual end-user because its scores reflect the perceived impair
38、ments due to coded audiovisual media data being transmitted over an IP connection with certain performance, and does not include specific terminal devices or user-specific. The scores predicted by a general quality model necessarily reflect average perceptual impairments. Effects such as those due t
39、o audio levels, signal noise and effects due to source generation such as video shake or certain colour properties (and other similar video or audio factors) and other impairments related to the payload are not reflected in the scores computed by this model. Therefore, it is possible to have high sc
40、ores with this model, yet have a poor overall stream quality. As a consequence, this Recommendation can be used for applications such as: In-service quality monitoring for specific IP-based audiovisual services, as specified in more detail below. Benchmarking of different service implementations. Ho
41、wever, it cannot be used for direct benchmarking of different encoder implementations. 2 Rec. ITU-T P.1203 (10/2017) 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 ti
42、me 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 edition of the Recommendations and other references listed below. A
43、 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.1022 Recommendation ITU-T G.1022 (2016), Buffer models for media streams on TCP trans
44、port. ITU-T H.264 Recommendation ITU-T H.264 (2012), Advanced video coding for generic audiovisual services. ITU-T P.800.1 Recommendation ITU-T P.800.1 (2006), Mean Opinion Score (MOS) terminology. ITU-T P.910 Recommendation ITU-T P.910 (2008), Subjective video quality assessment methods for multime
45、dia applications. ITU-T P.911 Recommendation ITU-T P.911 (1998), Subjective audiovisual quality assessment methods for multimedia applications. ITU-T P.1201.1 Recommendation ITU-T P.1201.1 (2012), Parametric non-intrusive assessment of audiovisual media streaming quality Lower resolution application
46、 area. ITU-T P.1201.2 Recommendation ITU-T P.1201.2 (2012), Parametric non-intrusive assessment of audiovisual media streaming quality Higher resolution application area. ITU-T P.1202 Recommendation ITU-T P.1202 (2012), Parametric non-intrusive bitstream assessment of video media streaming quality.
47、ITU-T P.1202.1 Recommendation ITU-T P.1202.1 (2012), Parametric non-intrusive bitstream assessment of video media streaming quality Lower resolution application area. ITU-T P.1203.1 Recommendation ITU-T P.1203.1 (2016), Parametric bitstream-based quality assessment of progressive download and adapti
48、ve audiovisual streaming services over reliable transport Video quality estimation module. ITU-T P.1203.2 Recommendation ITU-T P.1203.2 (2016), Parametric bitstream-based quality assessment of progressive download and adaptive audiovisual streaming services over reliable transport Audio quality esti
49、mation module. ITU-T P.1203.3 Recommendation ITU-T P.1203.3 (2016), Parametric bitstream-based quality assessment of progressive download and adaptive audiovisual streaming services over reliable transport Quality integration module. ITU-T P.1401 Recommendation ITU-T P.1401 (2012), Methods, metrics and procedures for statistical evaluation, qualification and comparison of objective quality prediction models. 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following term
