Comparative assessment of H.265/MPEG-HEVC, VP9, and H.264/MPEG-AVC encoders for low-delay video applications

Abstract

The popularity of low-delay video applications dramatically increased over the last years due to a rising demand for realtime video content (such as video conferencing or video surveillance), and also due to the increasing availability of relatively inexpensive heterogeneous devices (such as smartphones and tablets). To this end, this work presents a comparative assessment of the two latest video coding standards: H.265/MPEG-HEVC (High-Efficiency Video Coding), H.264/MPEG-AVC (Advanced Video Coding), and also of the VP9 proprietary video coding scheme. For evaluating H.264/MPEG-AVC, an open-source x264 encoder was selected, which has a multi-pass encoding mode, similarly to VP9. According to experimental results, which were obtained by using similar low-delay configurations for all three examined representative encoders, it was observed that H.265/MPEG-HEVC provides significant average bit-rate savings of <i>32.5%</i>, and <i>40.8%</i>, relative to VP9 and x264 for the <i>1-pass</i> encoding, and average bit-rate savings of <i>32.6%</i>, and <i>42.2%</i> for the <i>2-pass</i> encoding, respectively. On the other hand, compared to the x264 encoder, typical low-delay encoding times of the VP9 encoder, are about <i>2,000</i> times higher for the <i>1-pass</i> encoding, and are about <i>400</i> times higher for the <i>2-pass</i> encoding.