Objective measurement of transcoded video quality in mobile applications

Abstract

This paper evaluates the performance of a zero reference metric used in objective measurement of the quality of video which has been transcoded at various bit rates to suit the needs of the 3G mobile environment. This Zero reference metric (AVQ) has been shown to exhibit a high correlation with Mean Time Between Failures (MTBF) which is a functional measure of video quality representing how often a typical viewer observes a noticeable visual error. This paper reports on the performance of transcoders with MPEG2 video at 512 kbps as input and 192, 256 and 384 kbps versions of MPEG-4 Part 2 Visual and MPEG-4 Part 10 (H.264 ) as outputs. We use AVQ-estimated MTBF and PSNR as quality metrics. Our results show that MTBF better reflects subtleties such as lowered visual quality during significant motion. It also provides a more descriptive spread of quality in the 192-384 kbps range of transcoder outputs.