1、 International Telecommunication Union ITU-T P.1202.1TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (10/2012) SERIES P: TERMINALS AND SUBJECTIVE AND OBJECTIVE ASSESSMENT METHODS Models and tools for quality assessment of streamed media Parametric non-intrusive bitstream assessment of video media st
2、reaming quality Lower resolution application area Recommendation ITU-T P.1202.1 ITU-T P-SERIES RECOMMENDATIONS TERMINALS AND SUBJECTIVE AND OBJECTIVE ASSESSMENT METHODS Vocabulary and effects of transmission parameters on customer opinion of transmission quality Series P.10 Voice terminal characteri
3、stics 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 Methods for objective and subjective assessment of speech quality Series P.80 P.800 Audiovis
4、ual 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 and tools for quality assessment of streamed media Series P.1200Telemeeting assessment Series P.1300 Statistical analysis, ev
5、aluation 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.1202.1 (10/2012) i Recommendation ITU-T P.1202.1 Parametric non-intrusive bitstream assessment of video media streaming quality Lower resolutio
6、n application area Summary Recommendation ITU-T P.1202.1 specifies the algorithmic model for the lower resolution (LR) application area of ITU-T P.1202. The ITU-T P.1202 series of Recommendations specifies models for monitoring the video quality of IP-based video services based on packet-header and
7、bitstream information. The lower resolution application area of the ITU-T P.1202.1 part of ITU-T P.1202 can be applied to the monitoring of the performance and quality of experience (QoE) of video services such as mobile TV. This Recommendation includes an electronic attachment with test vectors for
8、 testing compliance. History Edition Recommendation Approval Study Group 1.0 ITU-T P.1202.1 2012-10-14 12 ii Rec. ITU-T P.1202.1 (10/2012) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communicati
9、on 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 on a worldwide basis. The Worl
10、d 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 down in WTSA Resolution 1. In
11、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 telecommunication administration and a recogn
12、ized 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 mandatory provisions are met. The wo
13、rds “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 attention to the possibility tha
14、t 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 others outside of the Recommendat
15、ion 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 the latest information and are t
16、herefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2013 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.1202.1 (10/2012) iii Table of Contents Page 1 Sc
17、ope 1 2 References. 1 3 Definitions 1 4 Abbreviations and acronyms 2 5 Conventions 2 6 Model description . 2 6.1 Extraction of basic parameters . 5 6.2 Aggregation of basic parameters into internal picture level parameters 11 6.3 Aggregation of parameters into model parameters 35 6.4 Quality estimat
18、ion model . 41 7 Assumptions . 49 8 Model compliance 49 8.1 Test vectors for extraction of basic parameters 50 8.2 Test vectors for aggregation of basic parameters into internal picture level parameters . 50 8.3 Test vectors for aggregation of parameters into model parameters . 50 8.4 Test vectors f
19、or quality estimation model 51 Electronic attachment: Test vectors for testing compliance Rec. ITU-T P.1202.1 (10/2012) 1 Recommendation ITU-T P.1202.1 Parametric non-intrusive bitstream assessment of video media streaming quality Lower resolution application area 1 Scope This Recommendation1describ
20、es an algorithmic model for parametric non-intrusive bitstream assessment of video media streaming quality lower resolution (LR) application area. This algorithmic model can be applied to the monitoring of the video quality of IP-based video services based on information extracted from the video bit
21、stream encoded with the ITU-T H.264/AVC baseline video codec. The model is intended especially for the lower resolution application area, including such services as mobile TV. The ITU-T P.1202.1 model is a no-reference (i.e., non-intrusive) model which operates by analysing information in the video
22、bitstream without fully decoding the bitstream. Further client specific information, such as concealment type and rebuffering duration, is provided to the algorithm out-of-band, for example in the form of stream-specific side information. As output, the model algorithm provides an estimate of the vi
23、deo quality in terms of the five-point absolute category rating (ACR) mean opinion score (MOS) scale defined in ITU-T P.910. This Recommendation describes the algorithm that takes an elementary stream encapsulated in RTP/UDP/IP as input, where information from RTP headers is used to identify lost pi
24、ctures. 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 time of publication, the editions indicated were valid. All Recommendations and other references are subject to
25、 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 ITU-T Recommendations is regularly published. The reference to a document within
26、 this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. ITU-T H.264 Recommendation ITU-T H.264 (2012), Advanced video coding for generic audiovisual services. ITU-T P.910 Recommendation ITU-T P.910 (2008), Subjective video quality assessment methods for mult
27、imedia applications. ITU-T P.1202 Recommendation ITU-T P.1202 (2012), Parametric non-intrusive bitstream assessment of video media streaming quality. IETF RFC 3550 IETF RFC 3550 (2003), RTP: A Transport Protocol for Real-Time Applications. IETF RFC 3984 IETF RFC 3984 (2005), RTP Payload Format for H
28、.264 Video. IETF RFC 4566 IETF RFC 4566 (2006), SDP: Session Description Protocol. 3 Definitions None. _ 1This Recommendation includes an electronic attachment with test vectors for testing compliance. 2 Rec. ITU-T P.1202.1 (10/2012) 4 Abbreviations and acronyms This Recommendation uses the followin
29、g abbreviations and acronyms: ACR Absolute Category Rating AVC Advanced Video Coding DCT Discrete Cosine Transform EC MB Error Concealed Macroblock GOP Group Of Pictures IP Internet Protocol MB Macroblock MOS Mean Opinion Score NAL Network Abstraction Layer PLC Packet Loss Concealment QP Quantizatio
30、n Parameter RTP Real Time Protocol SDP Session Description Protocol SPS Sequence Parameter Set UDP User Datagram Protocol 5 Conventions None. 6 Model description This clause describes the ITU-T P.1202.1 model and how it is implemented. The block diagram for the model is depicted in Figure 6-1. The m
31、odel takes an ITU-T H.264/AVC baseline encoded video bitstream and side information (error concealment type, rebuffering information, etc.) as input, extracts parameters, also referred to as features, and aggregates them into model parameters which are used to calculate an estimated video quality MO
32、S for the sequence. Rec. ITU-T P.1202.1 (10/2012) 3 Side informationBasic parameter extraction from sideinformationITU-T H.264 encoded video bitstreamBasic parameter extraction from SPSBasic parameter extraction atpicture levelAggregation of basic parameters intointernal picture level parametersEnd
33、ofsequence?NoYesAggregation of parameters into model parametersQuality estimation modelEstimated video MOSP.1202.1(12)_F6-1Figure 6-1 Block diagram for ITU-T P.1202.1 The model description is organized according to the flow of parameters in the model and to which degradation module the parameters be
34、long. Clause 6.1 describes the extraction of basic parameters from the video bitstream and side information. In clause 6.2 the algorithms for aggregating the basic parameters into internal parameters at picture level are described. The words picture and frame are used interchangeably throughout this
35、 Recommendation. The aggregation of parameters into model parameters is described in clause 6.3, and finally the quality estimation model is described in clause 6.4. Four different types of degradations are detected by the ITU-T P.1202.1 model; compression artefacts, slicing artefacts, freezing arte
36、facts and rebuffering artefacts. Compression artefacts are introduced due to lossy compression of the encoding process. Slicing artefacts are introduced when packet losses are concealed using a packet loss concealment (PLC) scheme trying to repair erroneous frames. Freezing artefacts are introduced
37、when the PLC scheme of the receiver replaces the erroneous frames (either due to packet loss or error propagation) with the previous error free frame until a decoded picture without errors has been received. Since the erroneous frames are not displayed, this type of artefact is also referred to as f
38、reezing with skipping. Rebuffering artefacts come from rebuffering events at the client side, which could be a result of video data arriving late. Usually, rebuffering events are indicated to the viewer, e.g., in the form of a spinning wheel. This is also referred to as freezing without skipping. Fo
39、r each clause a set of input and output parameters that are used by the algorithms are defined and described. Model coefficients are also given if it is being used by the algorithms. The flow chart in Figure 6-2 describes the flow of parameters in the model and in what clause each part can be found.
40、 4 Rec. ITU-T P.1202.1 (10/2012) P.1202.1(12)_F6-26.1 Extractionof basicparameters6.1.2 Extraction of basicparameters from SPS6.1.3 Extraction of basic parameters frombitstream at picture level6.1.1 Extraction of basicparameters from side info6.2.1 Compressionmodule parameters6.2.2 Slicingmodule par
41、ameters6.2 Aggregation of basicparameters into internalpicture level6.3 Aggregation ofparameters into modelparameter6.4 Qualityestimation model6.3.1 Compressionmodule parameters6.3.2 Slicingmodule parameters6.3.3 Freezingmodule parameters6.3.4 Rebufferingmodule parameters6.4.1 Compressionmodule6.4.2
42、 Slicingmodule6.4.3 Freezingmodule6.4.4 Rebufferingmodule6.4.5 Framework for combining modulesFigure 6-2 Flow of parameters in the model The algorithmic descriptions of the model are described using C-style pseudocode, leaving out variable declarations, row-ending semi-colons, etc., for better reada
43、bility. The variables in the algorithm descriptions are prefixed according to what variable type they pertain to, e.g., i_nbr_mbs. The prefixes have the following meaning: b boolean i integer d double, i.e., floating point value in double precision s string p struct or object holding data The follow
44、ing static code words are used for the macroblock data in the pseudocode of the algorithmic descriptions in this clause: INTER16x16_MB The macroblock is an inter macroblock divided into macroblock partitions of size 16x16. It is the same as P_L0_16x16 in ITU-T H.264. INTER16x8_MB The macroblock is a
45、n inter macroblock divided into macroblock partitions of size 16x8. It is the same as P_L0_L0_16x8 in ITU-T H.264. INTER8x16_MB The macroblock is an inter macroblock divided into macroblock partitions of size 8x16. It is the same as P_L0_L0_8x16 in ITU-T H.264. Rec. ITU-T P.1202.1 (10/2012) 5 INTER8
46、x8_MB The macroblock is an inter macroblock divided into macroblock partitions of size 8x8 with possibly different reference pictures for each macroblock partition. It is the same as P_8x8 in ITU-T H.264. INTER8x8REF0_MB The macroblock is an inter macroblock divided into macroblock partitions of siz
47、e 8x8 where all macroblock partitions uses the first reference picture in the list. It is the same as P_8x8ref0 in ITU-T H.264. SKIPPED_MB The macroblock is of skip type. INTRA_MB The macroblock is an intra-macroblock INTRA16x16_MB The macroblock is an intra-macroblock with 16x16 intra prediction mo
48、de. It is the same as Intra_16x16 in ITU-T H.264 with any setting of Intra16x16PredMode, CodedBlockPatternChroma and CodedBlockPatternLuma. LOST The macroblock has been lost UNKNOWN The type of the macroblock is unknown 6.1 Extraction of basic parameters The extraction of basic parameters is done fr
49、om side information; from sequence parameter set (SPS) network abstraction layer (NAL) units in the video bitstream, or from the picture level in the video bitstream. If an SPS NAL unit does not exist in the video bitstream, the output in clause 6.1.2.2 can be derived from session description protocol (SDP) data or from other side information. 6.1.1 Extraction of basic parameters from side information The basic parameter extraction from side information has the following input and output parameters:
