Comparison of Compression Efficiency between HEVC/H.265, VP9 and AV1 based on Subjective Quality Assessments

The growing requirements for broadcasting and streaming of high quality video continue to trigger demands for codecs with higher compression efficiency. AV1 is the most recent open and royalty free video coding specification developed by Alliance for Open Media (AOMedia) with a declared ambition of becoming the most popular next generation video coding standard. Primary alternatives to AV1 are the VP9 and the HEVC/H.265 which are currently among the most popular and widespread video codecs used in applications. VP9 is also a royalty free and open specification similar to AV1, while HEVC/H.265 requires specific licensing terms for its use in commercial products and services. In this paper, we compare AV1 to VP9 and HEVC/H.265 from rate distortion point of view in a broadcasting use case scenario. Mutual comparison is performed by means of subjective evaluations carried out in a controlled environment using HD video content with typical bitrates ranging from low to high, corresponding to very low up to completely transparent quality. We then proceed with an in-depth analysis of advantages and drawbacks of each codec for specific types of content and compare the subjective comparisons and conclusions to those obtained by others in the state of the art as well to those measured by means of objective metrics such as PSNR.