Energy Reduction Opportunities in HDR Video Encoding

TL;DR

This study examines energy consumption in HDR video encoding, revealing that lower bit-depth encoding can save energy and sometimes outperform 10-bit encoding at low bitrates, despite potential quality degradation.

Contribution

The paper provides a comparative analysis of energy efficiency in HDR video encoding across different bit depths and demonstrates conditions where 8-bit encoding is more efficient than 10-bit.

Findings

8-bit encoding can save significant energy compared to 10-bit.

At low bitrates, 8-bit encoding can outperform 10-bit in compression efficiency.

Linear luminance scaling causes visual quality degradation.

Abstract

This paper investigates the energy consumption of video encoding for high dynamic range videos. Specifically, we compare the energy consumption of the compression process using 10-bit input sequences, a tone-mapped 8-bit input sequence at 10-bit internal bit depth, and encoding an 8-bit input sequence using an encoder with an internal bit depth of 8 bit. We find that linear scaling of the luminance and chrominance values leads to degradations of the visual quality, but that significant encoding complexity and thus encoding energy can be saved. An important reason for this is the availability of vector instructions, which are not available for the 10-bit encoder. Furthermore, we find that at sufficiently low target bitrates, the compression efficiency at an internal bit depth of 8 bit exceeds the compression efficiency of regular 10-bit encoding.