A 120 fps High Frame Rate Real-time HEVC Video Encoder with Parallel Configuration Scalable to 4K

Abstract

This paper describes a new 120 fps (frames per second) real-time HEVC (High Efficiency Video Coding) encoder for HFR (high frame rate) video encoding and transmission. HFR provides more immersive viewing experience features by solving the problems created by fast moving scenes. Temporally scalable encoding with backward compatibility for legacy non-HFR systems is suitable for the rapid spread of HFR content delivery, avoiding the need to distribute multiple bitstreams of the same video with different frame rates. Such temporal scalability requires flexible encoder control functionalities to support newly-customized reference picture structures and dual-stream bitrate control. In this paper, modification in the customizable software architecture of encoder LSIs makes it possible to achieve 120 fps temporally scalable HEVC encoding for existing 60 fps-based systems. The encoder also achieves ${4\mathrm{K}/ 120\;\mathrm{fps}}$ video encoding in real time through the synchronized operation of multiple ${2\mathrm{K}/ 120\;\mathrm{fps}}$ encoders working in parallel. Our evaluations show that the bitrate increase rate from 60 fps to 120 fps under the same objective image quality condition are within the range of less than 57.2 percent in all video sequences and its average value is 53.8 percent. Both values are lower than that of the HM (HEVC reference software). The proposed encoder systems will open the door to the next generation high frame rate UHDTV (ultra high definition television) services.