HEVC subjective video quality test results

The primary goal for the development of the new High Efficiency Video Coding (HEVC) standard was to achieve a substantial improvement in compression efficiency relative to its predecessor, H.264/AVC. However, most comparisons to date had used simple objective measurements, rather than a formal subjective evaluation. Though objective tests are relatively easy to perform, their results can only be indicative of the actual quality perceived by viewers. This paper describes the verification tests that were conducted by the Joint Collaborative Team on Video Coding (JCT-VC) of ITU-T SG 16 WP 3 (VCEG) and ISO/IEC JTC 1/SC 29/WG 11 (MPEG). Both objective and subjective evaluations were conducted, comparing the HEVC Main profile to the H.264/AVC High profile. The tests used sequences with resolutions ranging from 480p to Ultra High Definition (UHD), encoded at various quality levels. The results showed that the subjective performance of HEVC is actually better than would be predicted from the objective test results. In 86% of the test cases, the subjective test results showed that HEVC required half or less of the bit-rate of the H.264/AVC reference to achieve comparable quality. The average bit-rate savings for test sequences at UHD, 1080p, 720p and 480p resolutions were found to be approximately 64%, 62%, 56% and 52%, respectively.