hdrldr

HDRLDR is a term used to describe the relationship between High Dynamic Range (HDR) content and Low Dynamic Range (LDR) displays, as well as the workflows that convert or adapt between the two. In practice, HDRLDR refers to techniques that enable HDR-created images and video to be presented on standard dynamic range devices while preserving as much perceptual detail as possible. It encompasses processes that bridge scene-referred HDR and display-referred LDR rendering.

HDR content captures a wider luminance range and a broader color gamut than conventional SDR content. LDR displays, with limited peak brightness and dynamic range, cannot reproduce this range directly. Therefore HDRLDR workflows rely on tone mapping and color management to compress or map the HDR signal into the constraints of the target display. Tone mapping aims to preserve important details in highlights and shadows while maintaining natural contrast, though the result can vary by operator choice or viewer preference. Gamut mapping may also be used to fit colors within the display’s capabilities.

Techniques used in HDRLDR include global and local tone mapping operators, exposure fusion, and perceptual mappings that simulate realistic lighting. Common HDR standards such as HDR10, HDR10+, Dolby Vision, and Hybrid Log-Gamma (HLG) influence how metadata guides the down-mapping to SDR. The workflow may be scene-referred (processing the raw scene data) or display-referred (preparing content for a specific device), with metadata aiding consistent results across devices.

Challenges include preserving detail, avoiding artifacts and banding, and aligning perceptual output with viewer expectations. HDRLDR remains central to delivering broad compatibility between HDR production pipelines and SDR viewing environments. Related topics include HDR, SDR, tone mapping, and color management.