The complexity of modern codecs along with the increased need of delivering high-quality videos at low bitrates has reinforced the idea of a per-clip tailoring of parameters for optimised rate-distortion performance. While the objective quality metrics used for Standard Dynamic Range (SDR) videos have been well studied, the transitioning of consumer displays to support High Dynamic Range (HDR) videos, poses a new challenge to rate-distortion optimisation. In this paper, we review the popular HDR metrics DeltaE100 (DE100), PSNRL100, wPSNR, and HDR-VQM. We measure the impact of employing these metrics in per-clip direct search optimisation of the rate-distortion Lagrange multiplier in AV1. We report, on 35 HDR videos, average Bjontegaard Delta Rate (BD-Rate) gains of 4.675%, 2.226%, and 7.253% in terms of DE100, PSNRL100, and HDR-VQM. We also show that the inclusion of chroma in the quality metrics has a significant impact on optimisation, which can only be partially addressed by the use of chroma offsets.

翻译：现代编解码器的复杂性以及以低比特率传输高质量视频需求的增加，强化了针对逐片段参数定制以优化率失真性能的观点。虽然标准动态范围（SDR）视频的客观质量度量已得到充分研究，但消费级显示器向支持高动态范围（HDR）视频的过渡，给率失真优化带来了新挑战。本文回顾了主流的HDR度量指标：DeltaE100（DE100）、PSNRL100、wPSNR和HDR-VQM。我们评估了在AV1中对率失真拉格朗日乘子进行逐片段直接搜索优化时，采用这些度量指标的影响。针对35个HDR视频，我们报告了以DE100、PSNRL100和HDR-VQM为标准的平均Bjontegaard Delta率（BD-Rate）增益分别为4.675%、2.226%和7.253%。此外，研究表明，在质量度量中纳入色度分量对优化结果有显著影响，而这种影响仅能通过使用色度偏移部分缓解。