High dynamic range (HDR) is an important emerging technology that touches acquisition, post production/DI (especially colour grading), studio display, mastering, distribution, and display in both the cinema and consumers’ premises. In this seminar, we’ll begin by outlining the theory of HDR - in particular, psychophysics and visual appearance aspects. The central topic, though, is the implementation and deployment of HDR in cinema and video. In particular, we’ll discuss metadata and its interpretation, and adaptation of the HDR system to varying display and viewing characteristics.
A few standards for HDR video are already in place, such as SMPTE ST 2084 (perceptual quantizer, PQ). However, current standards do not quite suffice for HDR distribution to consumers. At least three companies have announced HDR efforts that are (for the moment, at least) proprietary. Either proprietary solutions will take hold, or additional standards are needed - for example, standards for HDR metadata. Several organizations have made statements that suggest that SMPTE ST 2084 will suffice in distribution - but, the backwards compatibility story is far from clear. Some solutions are single-layer, some are two-layer; some solutions require 12‑bit video, others operate with 10‑bit video. Some solutions to production propose a final “trim pass” for introducing HDR; other solutions accommodate HDR in the whole post/DI pipeline. We will explore the approval process for post-production and live production. We will discuss metadata, both insertion (at the front-end of distribution) and interpretation (at the cinema and at consumers’ premises). We will outline the dangers of “creative” signal processing at consumers’ premises, and suggest some solutions. Emergent high dynamic range systems typically offer wide colour gamut; in theatre projection, laser illumination is now in use, and in consumer encoding may use BT.2020 primaries and native display primaries akin to DCI P3. We’ll explore the colour transform implications.
The field of HDR is rapidly evolving, in its technology, business, and standards arenas. Expect discussion of last-minute developments.