The perceptual quantizer (PQ), published by
SMPTE as SMPTE ST 2084,[1] is a
transfer function that allows for
HDR display by replacing the
gamma curve used in
SDR.[2][3][4][5] It is capable of representing luminance level up to 10000
cd/m2 (nits) and down to 0.0001 nits.[2] It has been developed by
Dolby[6] and standardized in 2014 by
SMPTE[1] and also in 2016 by
ITU in
Rec. 2100.[7][8] ITU specifies the use of PQ or
HLG as transfer functions for HDR-TV.[7] PQ is the basis of HDR video formats (such as
Dolby Vision,[2][9]HDR10[10] and
HDR10+[11]) and is also used for HDR still picture formats.[12][13] PQ is not backward compatible with the
BT.1886EOTF (i.e. the
gamma curve of
SDR), while
HLG is compatible.
PQ is a non-linear
transfer function based on the human visual perception of
banding and is able to produce no visible banding in 12 bits.[14] A power function (used as EOTFs in standard dynamic range applications) extended to 10000
cd/m2 would have required 15 bits.[14]