Comparative Study of 8 and 10-bit HEVC Encoders

Abstract

This paper compares the rate-distortion-complexity (RDC) characteristics of the HEVC Main 10 Profile (M10P) and Main Profile (MP) encoders. The evaluations are performed with HEVC reference encoder (HM) whose M10P and MP are benchmarked with different resolutions, frame rates, and bit depths. The reported RD results are based on bit rate differences for equal PSNR whereas complexities have been profiled with Intel VTune on Intel Core 2 processor. With our 10-bit 4K 120 fps test set, the average bit rate decrements of M10P over MP are 5.8%, 11.6%, and 12.3% in the all-intra (AI), random access (RA), and low-delay B (LB) configurations, respectively. Decreasing the bit depth of this test set to 8 lowers the RD gain of M10P only slightly to 5.4% (AI), 11.4% (RA), and 12.1% (LB). The similar trend continues in all our tests even though the RD gain of M10P is decreased over MP with lower resolutions and frame rates. M10P introduces no computational overhead in HM, but it is anticipated to increase complexity and double the memory usage in practical encoders. Hence, the 10-bit HEVC encoding with 8-bit input video is the most recommended option if computation and memory resources are adequate for it.