Benchmarking real-time HEVC streaming

Abstract

Work towards the standardisation of High Efficiency Video Coding (HEVC), the next generation video coding scheme, is currently gaining pace. HEVC offers the prospect of a 50% improvement in compression over the current H.264 Advanced Video Coding standard (H.264/AVC). Thus far, work on HEVC has concentrated on improvements to the coding efficiency and has not yet addressed transmission in networks other than to mandate byte stream compliance with Annex B of H.264/AVC. For practical networked HEVC applications a number of essential building blocks have yet to be defined. In this work, we design and prototype a real-time HEVC streaming system and empirically evaluate its performance, in particular we consider the robustness of the current Test Model under Consideration (TMuC HM4.0) for HEVC to packet loss caused by a reduction in available bandwidth both in terms of decoder resilience and degradation in perceptual video quality. A NAL unit packetisation and streaming framework for HEVC encoded video streams is designed, implemented and empirically tested in a number of streaming environments including wired, wireless, single path and multiple path network scenarios. As a first step the HEVC decoder’s error resilience is tested under a comprehensive set of packet loss conditions and a simple error concealment method for HEVC is implemented. Similarly to H.264 encoded streams, the size and distribution of NAL units within an HEVC stream and the nature of the NAL unit dependencies influences the packetisation and streaming strategies which may be employed for such streams. The relationships between HEVC encoding mode and the quality of the received video are shown under a wide range of bandwidth constraints. HEVC streaming is evaluated in both single and multipath network configuration scenarios. Through the use of extensive experimentation, we establish a comprehensive set of benchmarks for HEVC streaming in loss prone network environments. We show the visual quality reduction in terms of PSNR which results from a reduction in available bandwidth. To the best of our knowledge, this is the first time that such a fully functional streaming system for HEVC, together with the benchmark evaluation results, has been reported. This study will open up more timely research opportunities in this cutting edge area.