1、 IEC 62503 Edition 1.0 2008-09 INTERNATIONAL STANDARD NORME INTERNATIONALE Multimedia quality Method of assessment of synchronization of audio and video Qualit pour les systmes multimdia Mthode dvaluation de la synchronisation de laudio et de la vido IEC 62503:2008-09(en-fr) colour inside THIS PUBLI
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19、rez nous donner des commentaires sur cette publication ou si vous avez des questions contactez-nous: csciec.ch. IEC 62503 Edition 1.0 2008-09 INTERNATIONAL STANDARD NORME INTERNATIONALE Multimedia quality Method of assessment of synchronization of audio and video Qualit pour les systmes multimdia Mt
20、hode dvaluation de la synchronisation de laudio et de la vido INTERNATIONAL ELECTROTECHNICAL COMMISSION COMMISSION ELECTROTECHNIQUE INTERNATIONALE M ICS 33.160.01 PRICE CODE CODE PRIX ISBN 978-2-8322-1359-9 Registered trademark of the International Electrotechnical Commission Marque dpose de la Comm
21、ission Electrotechnique Internationale Warning! Make sure that you obtained this publication from an authorized distributor. Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agr. colour inside 2 IEC 62503:2008 IEC 2008 CONTENTS FOREWORD . 3 INTRODUCTION . 5
22、 1 Scope . 6 2 Normative reference . 6 3 Terms and definitions . 6 4 Overview of methods of assessment . 7 5 Subjective assessment of lip sync 7 5.1 Items to be assessed 7 5.2 Preparation of test video clips and test video sequence . 8 5.2.1 Selection of content of a test video clip 8 5.2.2 Creation
23、 of a test video sequence 8 5.3 Procedures and condition for assessment of lip sync at the section 3-3 9 5.4 Reporting of the result of assessment 9 6 Data processing . 10 6.1 Items to be assessed 10 6.2 Method of assessment. 10 6.3 Reporting of the result of estimation 11 Bibliography 12 Figure 1 O
24、verview 7 Figure 2 Preparation of test video clips with time shifted audio 8 Figure 3 An example of subjective assessment of lip sync . 10 Figure 4 Normalized response for grading impairment caused by lip sync mismatch . 11 Table 1 Five-grade impairment scale and explanation of subjective opinion sc
25、ore. 9 IEC 62503:2008 IEC 2008 3 INTERNATIONAL ELECTROTECHNICAL COMMISSION _ MULTIMEDIA QUALITY METHOD OF ASSESSMENT OF SYNCHRONIZATION OF AUDIO AND VIDEO FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrote
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36、for audio, video and multimedia systems, of IEC technical committee 100: Audio, video and multimedia systems and equipment. This bilingual version (2014-04) corresponds to the monolingual English version, published in 2008-09. The text of this standard is based on the following documents: CDV Report
37、 on voting 100/1277/CDV 100/1358/RVC Full information on the voting for the approval of this standard can be found in the report on voting indicated in the above table. The French version of this standard has not been voted upon. 4 IEC 62503:2008 IEC 2008 This publication has been drafted in accorda
38、nce with the ISO/IEC Directives, Part 2. The committee has decided that the contents of this publication will remain unchanged until the maintenance result date indicated on the IEC web site under “http:/webstore.iec.ch“ in the data related to the specific publication. At this date, the publication
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40、ment using a colour printer. IEC 62503:2008 IEC 2008 5 INTRODUCTION Contemporary multimedia systems are realized by digital technology. Depending on what digital processing is being applied, time delays differ among medium channels for reproduction as perceptible stimulus for a human audience. An ex
41、ample is video delay against audio, which is identified by such terms as lip sync or AV-sync. Video delay against audio will be inevitable for large sized displays, because necessary time for rendering and visualization will be proportional to the number of picture elements. There should also be add
42、itional factors to be considered. They include synchronization problem during medium gathering, production, post-production, processing in various aspects to combine these multiple media and to be sent out or recorded as “multimedia”. There is a need for international standards to provide the follow
43、ing three related methodologies: a) an objective method of measurement for difference of delays between reproduced audio and video (lip sync) by multimedia systems and equipment, b) a subjective (or perceptible) and statistical method of assessment of overall difference of delays between a real worl
44、d and a reproduced scene and sound, c) a method of estimation of implied difference of delays inherent in multimedia received, recorded or under reproduction. This International Standard addresses the item b) using typical multimedia content such as bust shots of news casters because of easiness in
45、defining synchronization of audio and video. Since a range of perceptibly allowable miss-synchronization and sensitivity of human audience for lead and delayed audio against accompanied video depends on human sensation and the conditions for assessment, a clearly defined method of assessment of such
46、 characteristics should be standardised. This International Standard is intended to supplement Recommendation ITU-R BT.1359-1, 1 1 , as well as partly answer the request of ITU-R to IEC that has been stated in Recommendation ITU-R BT.1377 2. Technical contents are based on a study in Faculty of Engi
47、neering, Chiba University in Japan, conducted in April 2006. _ 1Numbers in square brackets refer to the Bibliography. 6 IEC 62503:2008 IEC 2008 MULTIMEDIA QUALITY METHOD OF ASSESSMENT OF SYNCHRONIZATION OF AUDIO AND VIDEO 1 Scope This International Standard provides a subjective (or perceptible) and
48、 statistical method of assessment of overall, or end-to-end, difference of delays between real world and reproduced scenes in terms of video and accompanying audio recoded in a medium. This International Standard does not specify limiting values for those results obtained by the application of the p
49、rovisions in this standard. It excludes applications to professional broadcast systems. 2 Normative reference The following referenced document is indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ITU-R BT.500-11:2002, Methodology for the su