HDR Challenges and Solutions

For content producers who need to make drastic choices to allocate limited contrast and colors in standard dynamic range (SDR), high dynamic range (HDR) offers the opportunity to show more. This means greater freedom and flexibility for their storytelling. However, future-proof HDR content presents its own challenges, for example, the wide variation in HDR display capabilities and the desire to have any production, HDR or SDR, play optimally on any display, HDR or SDR. The typical solution to this issue is tone mapping, whether a tone compression to map from HDR to a lower HDR or SDR luminance, or tone expansion to map from SDR or HDR to a higher HDR luminance. Various techniques of tone mapping, including hybrid log-gamma (HLG), static look-up tables (LUTs) and dynamic metadata, are considered, and the relative advantages and performance are analyzed. A proposed solution that has been introduced in practice, “Advanced HDR by Technicolor,” is described.