Efficient Software H.264/AVC to HEVC Transcoding on Distributed Multicore Processors

The latest High Efficiency Video Coding (HEVC) standard achieves a significant compression efficiency improvement over the H.264/Advanced Video Coding (AVC) standard, but with a much higher computational complexity. In this paper, we propose a novel framework for software-based H.264/AVC to HEVC transcoding, integrated with tools such as wavefront parallel processing that are useful for achieving higher levels of parallelism on multicore processors and distributed systems. By utilizing information extracted from the input H.264/AVC bitstream, the transcoding process can be greatly accelerated with a visual quality loss that is modest for many applications. Based on the HEVC HM 14.0 reference software and using standard HEVC test bitstreams, the proposed transcoder can achieve up to 60× speedup on a Quad Core 8-thread server over decoding-re-encoding based on FFMPEG and the HM software with a BD-rate loss of 15%-20%. By implementing a group of picture-level task distribution on a distributed system with nine processing units, the proposed software transcoder can achieve a speed for transcoding 720 p at 30 Hz in real time.