Rate-distortion and energy performance of HEVC and H.264/AVC encoders: A comparative analysis

A quantitative, systematic, and detailed analysis of the energy impacts of the tools that comprise two of the most recent video coding standards: the High Efficiency Video Coding (HEVC) and the H.264/AVC is presented. Our comparative study measures the energy consumption effects of important video-coding parameters, like Search Range (SR), Quantization Parameter (QP), and video resolution on both encoders. The obtained results for HEVC showed, for the Random Access (RA) prediction structure, gains of 25% in BD-Rate over H.264/AVC at the expense of 17% higher energy consumption. A new metric we defined herein, called BD-Energy, was used in the SR analysis, and the results from this investigation showed HEVC achieved an energy consumption up to 37.6% higher for a BD-Rate gain of 32.2%. The QP analysis demonstrated that the energy consumption gap between both encoders varies greatly as QP increases, resulting in a 15.08% difference from QP 22 to QP 37, on average. The major finding from our work is that the HEVC encoder presents better results in the energy/compression trade-off, but this efficiency is reduced as encoding becomes more complex, as our results discovered that the HEVC energy consumption scales faster.