Stephen D. Voran and Stephen Wolf

Abstract: Working Group T1A1.5 is supporting ITU-T Study Group 12 in developing subjective audiovisual testing methods under Question 22/12 which addresses audiovisual quality in multimedia services. A previous contribution from Bellcore, T1A1.5/93-104, describes three basic tests that can be used to examine how perceived audio quality and perceived video quality combine to create a perceived level of composite audiovisual quality. These tests provide a logical and important first step toward understanding the components of subjective audiovisual quality. The present contribution identifies two additional tests that could supplement the three basic tests by providing information about the interactions between perceived audio and video quality. The five resulting tests are summarized in tabular form. Key ideas from this contribution could be integrated with those presented in T1A1.5/93-104 to create a proposed U.S. Contribution to ITU-T Study Group 12. When the authors presented this document at the meeting, they suggested that the McGurk Effect might be exploited to provide quality information and diagnostic information for audio-visual systems. ITS staff created a videotape to demonstrate the McGurk Effect, and that tape was shown at the meeting. A .mov file (8 MB) and a .avi file (27 MB) of that demonstration are available. The McGurk Effect is most pronounced in the .avi file, since the video in that file has been compressed less.

Keywords: performance; video; quality; subjective; Testing; audio; audiovisual; interactions; framework

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