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 J.343.4 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (11/2014) SERIES J: CABLE NETWORKS AND TRANSMISSION OF TELEVISION, SOUND PROGRAMME AND OTHER MULTIMEDIA SIGNALS Measurement of the quality of service - Part 3 Hybrid-R
2、R objective perceptual video quality measurement for HDTV and multimedia IP-based video services in the presence of a reduced reference signal and non-encrypted bitstream data Recommendation ITU-T J.343.4 Rec. ITU-T J.343.4 (11/2014) i Recommendation ITU-T J.343.4 Hybrid-RR objective perceptual vide
3、o quality measurement for HDTV and multimedia IP-based video services in the presence of a reduced reference signal and non-encrypted bitstream data Summary Recommendation ITU-T J.343.4 provides Hybrid-reduced reference (Hybrid-RR) objective perceptual video quality measurement methods for HDTV and
4、multimedia when a reduced reference signal and non-encrypted bitstream data are available. The following list shows example applications that can use this Recommendation: potentially real-time, in-service quality monitoring at the head-end; video television streams over cable/IPTV networks including
5、 those transmitted over the Internet using Internet protocol; video quality monitoring at the receiver when a reduced reference signal and non-encrypted bitstream data are available; video quality monitoring at measurement nodes located between point of transmission and point of reception when a red
6、uced reference signal and non-encrypted bitstream data are available; quality measurement for monitoring of a transmission system that utilizes video compression and decompression techniques, either a single pass or a concatenation of such techniques; lab testing of video transmission systems. This
7、Recommendation includes an electronic attachment containing test vectors, including video sequences, bitstream files and predicted objective model scores. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T J.343.4 2014-11-29 9 11.1002/1000/12319 _ * To access the Recommendation
8、, 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. ii Rec. ITU-T J.343.4 (11/2014) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialize
9、d 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 Recommendations on them with a
10、 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 of ITU-T Recomme
11、ndations 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“ is used for conc
12、iseness 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 with the Recommend
13、ation 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 required of any party.
14、 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 applicability of claimed Intellectual Property Right
15、s, 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, implementers are
16、 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 2015 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permissio
17、n of ITU. Rec. ITU-T J.343.4 (11/2014) iii Table of Contents Page 1 Scope . 1 1.1 Applications 2 1.2 Limitations 2 2 References . 3 3 Definitions 3 4 Abbreviations and acronyms 3 5 Conventions 4 6 Performance metrics . 4 7 Description of the hybrid reduced-reference methodology 4 8 Models 5 Annex A
18、The YHyRR model 6 A.1 Introduction 6 A.2 Hybrid-RR video quality metric computation 6 Bibliography. 12 Electronic attachment: Test vectors, including video sequences, bitstream files and predicted objective model scores. Rec. ITU-T J.343.4 (11/2014) 1 Recommendation ITU-T J.343.4 Hybrid-RR objective
19、 perceptual video quality measurement for HDTV and multimedia IP-based video services in the presence of a reduced reference signal and non-encrypted bitstream data 1 Scope This Recommendation1 describes algorithmic models for measuring the visual quality of IP-based video services. The models are h
20、ybrid-reduced reference (Hybrid-RR) models, which use features extracted from the unimpaired reference video signal, the non-encrypted bitstream data and the video image data captured at the video player. As output, the models provide an estimate of visual quality on the 1,5 difference mean opinion
21、score (DMOS) scale, derived from five-point absolute category rating (ACR) as in ITU-T P.910. The models address low resolution (VGA/WVGA) application areas, including services such as mobile TV, as well as high resolution (HD) application areas, including services such as IPTV. This Recommendation
22、is to be used with video encoded using ITU-T H.264 and media payload encapsulated in RTP/UDP/IP packets for low resolution video and encapsulated in MPEG-TS/RTP/UDP/IP for high resolution video. The models in this Recommendation measure the visual effect of spatial and temporal degradations as a res
23、ult of video coding, erroneous transmission, or video rescaling. The models may be used for applications such as to monitor the quality of deployed networks to ensure their operational readiness or to benchmark service quality. The models in this Recommendation can also be used for lab testing of vi
24、deo transmission systems. The models identified in this Recommendation have limited precision. Therefore, directly comparing model results can be misleading. The accuracy of models has to be understood and taken into account (e.g., using ITU-T J.149). The validation test material consisted of video
25、encoded using different implementations of ITU-T H.264. It included media transmitted over wired and wireless networks, such as WIFI and 3G mobile networks. The transmission impairments included error conditions, such as dropped packets and packet delay, from simulations and from transmission over c
26、ommercially operated networks. The following source reference channel (SRC) conditions were included in the validation test: 1080i 60 Hz (29.97 fps); 1080p (25 fps); 1080i 50 Hz (25 fps); 1080p (29.97 fps); SRC duration: HD: 10 s, VGA/WVGA: 10 s or 15 s (rebuffering); VGA at 25 and 30 frames-per-sec
27、ond; WVGA at 25 and 30 frames-per-second. _ 1 This Recommendation includes an electronic attachment containing test vectors, including video sequences, bitstream files and predicted objective model scores. 2 Rec. ITU-T J.343.4 (11/2014) The following hypothetical reference circuit (HRC) conditions w
28、ere included in the validation test for each resolution: Test factors Video resolution: 1920 1080 interlaced and progressive Video frame rates 29.97 and 25 frames per second Video bitrates: 1 to 30 Mbit/s (HD), 100 kbit/s to 3 Mbit/s (VGA/WVGA) Temporal frame freezing (pausing with skipping) of up t
29、o 50% of video duration Transmission errors with packet loss Rebuffering (VGQ/WVGA only): up to 50% of SRC Coding technologies ITU-T H.264/AVC (MPEG-4 Part 10) Tandem coding 1.1 Applications The applications for the estimation model described in this Recommendation include, but are not limited to: P
30、otentially real-time, in-service quality monitoring at the headend. Video television streams over cable/IPTV networks including those transmitted over the Internet using Internet Protocol. Video quality monitoring at the receiver when side-channels and non-encrypted bitstream data are available. Vid
31、eo quality monitoring at measurement nodes located between the point of transmission and the point of reception when side-channels and non-encrypted bitstream data are available. Quality measurement for monitoring of a transmission system that utilizes video compression and decompression techniques,
32、 either as a single pass or as a concatenation of such techniques. Lab testing of video transmission systems. 1.2 Limitations The video quality estimation model described in this Recommendation cannot be used to fully replace subjective testing. When frame freezing was present, the test conditions h
33、ad frame freezing durations up to 50% of SRC duration. The models in this Recommendation were validated for measuring video quality in a re-buffering condition (i.e., video that has a steadily increasing delay or freezing without skipping) only for VGA/WVGA. The models were not tested on frame rates
34、 other than those used in TV systems (i.e., 29.97 frames per second and 25 frames per second, in interlaced or progressive mode). The models in this Recommendation may not be used if forward error correction techniques are employed. It is important that no additional transmission errors occur betwee
35、n the collection point of the bitstream data and the capture point of the processed video sequence (PVS). It should be noted that the objective model may produce erroneous results if new coding and transmission technologies produce artifacts that were not included in the validation tests. Here, a su
36、bjective evaluation is required. Rec. ITU-T J.343.4 (11/2014) 3 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.
37、 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 list of the currently valid ITU-T Recommendations is
38、 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 H.264 Recommendation ITU-T H.264 (2014), Advanced video coding for generic audiovisual services. ITU-T J.149 Recommendation ITU-T J.149 (200
39、4), Method for specifying accuracy and cross-calibration of Video Quality Metrics (VQM). ITU-T J.342 Recommendation ITU-T J.342 (2011), Objective multimedia video quality measurement of HDTV for digital cable television in the presence of a reduced reference signal. ITU-T J.343 Recommendation ITU-T
40、J.343 (2014), Hybrid perceptual/bitstream models for objective video quality measurements. ITU-T P.910 Recommendation ITU-T P.910 (2008), Subjective video quality assessment methods for multimedia applications. 3 Definitions This Recommendation uses the following term defined elsewhere: 3.1 hybrid r
41、educed reference model ITU-T J.343: An objective video quality model that predicts subjective quality using the decoded video frames, packet headers, video payload and features extracted from the reference video. Such models can be deployed in-service but cannot analyse encrypted video. 4 Abbreviati
42、ons and acronyms This Recommendation uses the following abbreviations and acronyms: CODEC Coder-Decoder DMOS Difference Mean Opinion Score EPSNR Edge Peak Signal-to-Noise Ratio ES Elementary bitStream HRC Hypothetical Reference Circuit Hybrid-RR Hybrid Reduced Reference model LUT Look-Up Table MPEG
43、Moving Picture Experts Group PES Packetized Elementary bitStream PVS Processed Video Sequence QP Quantization Parameter RR Reduced Reference STB Set-Top Box SRC Source Reference Channel or Circuit 4 Rec. ITU-T J.343.4 (11/2014) VQEG Video Quality Experts Group VQM Video Quality Metric VGA Video Grap
44、hics Array WVGA Wide Video Graphics Array 5 Conventions None. 6 Performance metrics A summary of this and other Hybrid models may be found in ITU-T J.343. See b-VQEG Hybrid for the complete analysis of the models included in this Recommendation. 7 Description of the hybrid reduced-reference methodol
45、ogy This Recommendation specifies objective video quality measurement methods which use both processed video sequences and bitstream data. The bitstream data may be provided in the forms of elementary bitstream (ES), packetized elementary bitstream (PES) or packet video (Figure 1). In addition, Hybr
46、id-RR models also use features extracted from source video sequences. Figure 2 shows a Hybrid-RR model. In addition to the non-encrypted bitstream data, the Hybrid-RR model uses the features extracted from the SRC. Figure 1 Block-diagram depicting the core concept of hybrid perceptual/bitstream mode
47、ls Rec. ITU-T J.343.4 (11/2014) 5 DMOSp: predicted DMOS by the model STB: Set-Top Box Figure 2 Block-diagram depicting the Hybrid-RR model 8 Models Annex A contains a full disclosure of all models included in this Recommendation. That model is referred to as YHyRR. 6 Rec. ITU-T J.343.4 (11/2014) Ann
48、ex A The YHyRR model (Hybrid-RR Model) (This annex forms an integral part of this Recommendation.) A.1 Introduction The YHyRR model first computes a video quality metric (VQM) value using the quantization parameter (QP) and the error area (log) using a pre-defined look-up-table. Then, the EPSNR valu
49、e is computed using ITU-T J.342. Finally, post-processing is applied to reflect various impairments due to transmission errors. A.2 Hybrid-RR video quality metric computation A.2.1 Feature computation A.2.1.1 Quantization parameter (QP) and error area In ITU-T H.264 advanced video coding (AVC) the QP is an important factor for video quality. The averaged QP and I frame QP are computed as follows: where NumFrame is the total number of frames and NumFrame is the number
