Perceptual quantizer

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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 was 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.1886 EOTF (i.e. the gamma curve of SDR), while HLG is compatible.

Contents

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]

Technical details

The PQ EOTF (electro-optical transfer function) is as follows: [7] [15]

The PQ inverse EOTF is as follows:

where

See also

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References

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