This document relates to high dynamic range (HDR) and wide color gamut (WCG) video distribution, based on HEVC, and when applicable on AVC, using either single-layer or dual-layer coding. This document serves several purposes. It covers some use cases of HDR/WCG video content. It reviews approaches, using SEI messages, to enable backward compatibility with legacy decoding systems that do not have the ability to detect, decode, or properly display HDR/WCG video content. It also describes methods for adapting HDR/WCG video content for use with display technologies in which the dynamic range and colour gamut capability differs from the original content. The document surveys the signalling mechanisms for handling HDR/WCG video with HEVC, and when applicable, with AVC. Indicators are provided for usage of the ICtCp colour representation, the hybrid log-gamma (HLG) and Perceptual Quantizer (PQ) transfer functions, and usage of different specific SEI messages for SDR backward compatibility and display adaptation functionalities. A dual-layer coding approach using the Scalable Main 10 profile of HEVC for backward compatibility with standard dynamic range (SDR) systems is also documented.
This report complements the material provided in another report, "Conversion and Coding Practices for HDR/WCG Y′CbCr 4:2:0 Video with PQ Transfer Characteristics". In brief, it reviews the use of certain SEI messages to achieve the capabilities mentioned above.