Assessing objective video quality in systems with multi-generation transcoding

Abstract

In a multi-generation transcoding system, the source may be an encoded mezzanine video whose objective video quality metrics (e.g., PSNR, SSIM) are unknown. Transcoding process yields objective quality metrics that are relative to the encoded source video, which does not indicate the actual quality of the transcoded video relative to the original uncompressed reference video. In this paper, we present an approach for estimating the objective quality metrics of the encoded mezzanine and demonstrate that it has higher accuracy compared to a well-known scheme. Finally, we derive bounds for the end-to-end objective quality metrics of the transcoded video, and use it for controlling the transcoding process to ensure that the final transcoded video satisfies a quality criterion.