Rate-distortion and energy performance of HEVC video encoders

A quantitative and systematic analysis of the energy impacts of the tools that comprise the most recent video-coding standard - the High Efficiency Video Coding (HEVC) - is comprehensively presented in this paper. Our comparative study measures the energy consumption effects of several video coding parameters, like Motion Estimation Search Range (SR), Quantization Parameter (QP), and video resolution on a general purpose platform. In order to jointly compare important video-coding results like bitrate and PSNR, three new metrics that combines these values with the energy consumption are proposed, namely: (i) BD-Energy; (ii) ECR (Energy-Compression Rate); and (iii) WNERD (Weighted Normalized Energy Compression Distortion). We conclude in our analysis that increasing the SR causes little to no gains in compression, whereas the energy consumption increases constantly. In the RA prediction structure, the average compression gains achieved were 0.48%, while the energy consumption increased by 13.7% on average. For LB configuration, a similar result was obtained: 0.08% of BD-Rate Savings at the expense of a 19.6% energy increase. The QP investigation demonstrates that compression efficiency and energy consumption are greatly affected as this parameter increases, and there is no QP capable of maximizing the three axes of optimization (rate, distortion, and energy).