Module hdr 

HDR sources brought into the SDR working space.

The working space is display-referred linear BT.709 with 1.0 at SDR white. HDR is linearized to nits (PQ by its EOTF; HLG by inverse OETF plus the BT.2100 OOTF at its nominal peak), converted to BT.709, and tone-mapped to SDR white by the BT.2390 EETF applied to the largest component, preserving hue. Out-of-gamut components clip at zero.

The YUV conversion shader implements these; GPU tests compare the two.

Structs

HdrToneMap

How an HDR source is tone-mapped: from source_peak_nits to SDR white.

Constants

DEFAULT_HDR_PEAK_NITS

Assumed HDR source peak when a project does not specify one.

SDR_WHITE_NITS

Luminance of SDR white (working-space 1.0), in nits.

Functions

bt2390_eetf

ITU-R BT.2390 EETF mapping nits from source_peak to target_peak, black at zero.

gamut_matrix

Linear RGB matrix (rows) from from to to primaries, D65 white. BT.601 is treated as BT.709, as the SDR path does.

hdr_to_working

Working-space linear RGB of an HDR pixel’s nonlinear components in its own primaries.

hlg_inverse_oetf

Scene light in 0..=1 of an HLG code value (the inverse OETF).

hlg_ootf

Display light in nits of HLG scene light shown at peak_nits: the BT.2100 OOTF, with the system gamma for that peak.

pq_eotf

Display luminance, in nits, of a PQ code value in 0..=1.

pq_inverse_eotf

The PQ code value of a display luminance in nits.