IEC TR 62251:2003

Multimedia systems and equipment - Quality assessment - Audio-video communication systems

specifies items to be measured by objective methods, methods of measurement together with measuring conditions, processing of the measured data and presentation of acquired information for objective assessment of end-to-end quality of audio-video communication systems over digital networks. The measurements are supposed to be conducted in a double-ended and a full reference. The systems are assumed to have electrical interface channels at the input and at the output of audio-video signals for objective assessment.

General Information

• Status: Published
• Publication Date: 15-May-2003
• ICS: 01 - GENERALITIES. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION
• ICS: 33.160.60 - Multimedia systems and teleconferencing equipment
• Technical Committee: TA 20 - Analogue and digital audio
• Current Stage: PPUB - Publication issued
• Start Date: 15-Jul-2003
• Completion Date: 16-May-2003

Standards Content (Sample)

TECHNICAL IEC
REPORT
TR 62251
First edition
2003-05
Multimedia systems and equipment –
Quality assessment –
Audio-video communication systems
Reference number
IEC/TR 62251:2003(E)
Publication numbering
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TECHNICAL IEC
REPORT
TR 62251
First edition
2003-05
Multimedia systems and equipment –
Quality assessment –
Audio-video communication systems
 IEC 2003  Copyright - all rights reserved
No part of this publication may be reproduced or utilized in any form or by any means, electronic or
mechanical, including photocopying and microfilm, without permission in writing from the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
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International Electrotechnical Commission
Международная Электротехническая Комиссия
For price, see current catalogue

– 2 – TR 62251  IEC:2003(E)
CONTENTS
FOREWORD . 4
1 Scope . 5
2 References . 5
3 Terms and definitions . 6
4 Configuration for quality assessment . 6
4.1 Input and output channels. 6
4.2 Points of input and output terminals. 7
5 Video quality. 8
5.1 Introduction . 8
5.2 End-to-end tone reproduction . 9
5.3 End-to-end colour reproduction.11
5.4 End-to-end colour differences .12
5.5 End-to-end peak-signal to noise ratio (PSNR).16
5.6 End-to-end objective assessment of video quality.20
6 Audio quality.21
6.1 Perceived audio quality with full-reference signals .21
6.2 Sampling rate and quantization resolution .23
6.3 Delay.24
7 Total quality.24
7.1 Synchronization of audio and video (lip sync) .24
7.2 Scalability.25
7.3 Overall quality .26
Annex A (informative) PSNR’s defined in three-dimensional spaces applied to
hypothetical deterioration over the reference video sources .27
Annex B (informative) End-to-end objective assessment of video quality in spatial
frequency domain.31
Annex C (informative) PEAQ objective measurement method outline .36
Bibliography.40
Figure 1 – Model of audio-video communication systems . 7
Figure 2 – Schematic diagram for quality assessment . 7
Figure 3 – The image of the grey steps defined in IEC 61146-1. 9
Figure 4 – An example plot of tone reproduction .10
Figure 5 – The image of the colour reproduction chart defined in IEC 61146-1 .11
Figure 6 – Colour differences between reference and streamed video frames at 250 kbps
and 30 fps .15
Figure 7 – Examples of PSNR assessment.19
Figure 8 – Basic concept for making objective measurements .22
Figure 9 – Representation of PEAQ model .22
Figure B.1 – Assignment of the block numbers.31
Figure B.2 – Example of wavelet decomposition visualised .31

TR 62251  IEC:2003(E) – 3 –
Figure B.3 – Trends of difference of coefficients of wavelet transform between
reference and streamed video frames at 250 kbps and 30 fps .34
Figure C.1 – Basic concept for making objective measurements .36
Figure C.2 – Representation of PEAQ model.37
Figure C.3 – FFT based ear model, PEAQ basic version .37
Figure C.4 – Filter bank based ear model, PEAQ advanced version .38
Table 1 – An example of tone reproduction .10
Table 2 – An example of colour reproduction.12
Table 3 – Grand averages of colour differences .16
Table 4 – Overall PNSR’s averaged over the frames .20
Table 5 – Test items and resulting DI and ODG values for the basic version .23
Table 6 – Test items and resulting DI and ODG values for the advanced version .23
Table A.1 – Reference video sources available for objective assessment.27
Table A.2 – PSNR’s in various colour spaces and the colour difference for SRC13
and SRC14 .28
Table A.3 – PSNR’s in various colour spaces and the colour difference for SRC15
and SRC16 .28
Table A.4 – PSNR’s in various colour spaces and the colour difference for SRC17
and SRC18 .29
Table A.5 – PSNR’s in various colour spaces and the colour difference for SRC19
and SRC20 .29
Table A.6 – PSNR’s in various colour spaces and the colour difference for SRC21
and SRC22 .30
Table B.1 – Summary of difference of coefficients of wavelet coefficients.35
Table C.1 – Model output variables, PEAQ basic version .38
Table C.2 – Model output variables, PEAQ advanced version .39

– 4 – TR 62251  IEC:2003(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
MULTIMEDIA SYSTEMS AND EQUIPMENT –
QUALITY ASSESSMENT –
AUDIO-VIDEO COMMUNICATION SYSTEMS
FOREWORD
1) The IEC (International Electrotechnical Commission) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of the IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, the IEC publishes International Standards. Their preparation is
entrusted to technical committees; any IEC National Committee interested in the subject dealt with may
participate in this preparatory work. International, governmental and non-governmental organizations liaising
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Organization for Standardization (ISO) in accordance with conditions determined by agreement between the
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international consensus of opinion on the relevant subjects since each technical committee has representation
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of standards, technical specifications, technical reports or guides and they are accepted by the National
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Standards transparently to the maximum extent possible in their national and regional standards. Any
divergence between the IEC Standard and the corresponding national or regional standard shall be clearly
indicated in the latter.
5) The IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with one of its standards.
6) Attention is drawn to the possibility that some of the elements of this technical report may be the subject of
patent rights. The IEC shall not be held responsible for identifying any or all such patent rights.
The main task of IEC technical committees is to prepare International Standards. However, a
technical committee may propose the publication of a technical report when it has collected
data of a different kind from that which is normally published as an International Standard, for
example "state of the art".
Technical reports do not necessarily have to be reviewed until the data they provide are
considered to be no longer valid or useful by the maintenance team.
IEC 62251, which is a Technical Report, has been prepared by IEC technical committee 100:
Audio, Video and Multimedia Systems and Equipment.
The text of this technical report is based on the following documents:
Enquiry draft Report on voting
100/561/DTR 100/662/RVC
Full information on the voting for the approval of this technical report can be found in the
report on voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

TR 62251  IEC:2003(E) – 5 –
MULTIMEDIA SYSTEMS AND EQUIPMENT –
QUALITY ASSESSMENT –
AUDIO-VIDEO COMMUNICATION SYSTEMS
1 Scope
This Technical Report specifies items to be measured by objective methods, methods of
measurement together with measuring conditions, processing of the measured data and
presentation of acquired information for objective assessment of end-to-end quality of audio-
video communication systems over digital networks. The measurements are supposed to be
conducted in a double-ended and a full reference. The systems are assumed to have
electrical interface channels at the input and at the output of audio-video signals for objective
assessment.
The extension for systems that do not have such channels is left for further study.
2 Normative references
The following referenced documents are indispensable for the application of this document.
For dated references, only the edition cited applies. For undated references, the latest edition
of the referenced do
...