Optimization of HEVC λ-domain rate control algorithm for HDR video

Rate Control (RC) will play an important role in conceiving high-fidelity HDR video distribution through transmission and broadcast in imminent future. However, as video coding standards, like HEVC, are generally designed and optimized for the LDR content, this can result in an inefficient HDR video compression in the Rate-Distortion (RD) sense. In this paper, the state-of-the-art HEVC λ-domain RC algorithm is optimized for HDR video coding by proposing a new λ-QP relation after investigating the suitable RD model for HDR content. The updated RC algorithm with proposed relation outperforms the default HEVC RC algorithm achieving averaged PU-PSNR improvements of up to 1.36 dB for HDR video test sequences. Further, performance improvement is also evident from the HDR-VDP-2.2 Q and HDR-VQM based RD performance curves.