Quality assessment of an HDR dual-layer backward-compatible codec compared to uncompromised SDR and HDR solutions

Broadcasting high dynamic range (HDR) video has been demonstrated as largely preferred when compared to standard dynamic range (SDR), mainly due to its capability of representing more details in dark and bright regions. Additionally, progress over the last decades on creation, compression, transmission and rendering of HDR content signals a forthcoming deployment of HDR broadcasting services. Lack of a widely supported recommendation regarding bandwidth allocation for HDR compressed streams or a unique compression approach, prevent faster deployment of such services. This paper investigates the performance of a dual-layer backward-compatible compression codec, when compared to state-of-the-art HDR compression strategies, in terms of perceived quality. The evaluated system is a dual-layer compression scheme enabling the transmission of a backward-compatible SDR stream along with an HDR stream, reconstructed from the residual-based enhancement layer and SDR mapping (i.e. prediction). Comparison is made to two compression strategies realizing uncompromised SDR or HDR through the use of single layer systems multiplexed with metadata. Metadata contains information necessary to map HDR into SDR or SDR into HDR streams. Our conclusion provides guidance regarding the compression strategy to use as well as bandwidth allocation for HDR delivery, ensuring both SDR and HDR contents with perceptually acceptable quality.