Rec. 2100
![](../I/m/CIExy1931_Rec_2020.svg.png)
ITU-R Recommendation BT.2100, more commonly known by the abbreviations Rec. 2100 or BT.2100, defines various aspects of high dynamic range (HDR) video such as display resolution (HDTV and UHDTV), frame rate, chroma subsampling, bit depth, color space, and optical transfer function.[1][2] It was posted on the International Telecommunication Union (ITU) website on July 4, 2016.[1][2] Rec. 2100 expands on several aspects of Rec. 2020.[2]
Resolution
Rec. 2100 defines three resolutions of 1080p, 3840 × 2160 ("4K"), and 7680 × 4320 ("8K").[1] These resolutions have an aspect ratio of 16:9 and use square pixels.[1]
Frame rate
Rec. 2100 specifies the following frame rates: 120p, 119.88p, 100p, 60p, 59.94p, 50p, 30p, 29.97p, 25p, 24p, 23.976p.[1] Only progressive scan frame rates are allowed.[1]
Digital representation
Rec. 2100 defines a bit depth of either 10-bits per sample or 12-bits per sample.[1] Rec. 2100 allows for either narrow range or full range video signals.[1]
System colorimetry
Color space | White point | Primary colors | ||||||
---|---|---|---|---|---|---|---|---|
xW | yW | xR | yR | xG | yG | xB | yB | |
ITU-R BT.2100 | 0.3127 | 0.3290 | 0.708 | 0.292 | 0.170 | 0.797 | 0.131 | 0.046 |
The Rec. 2100 has the same color space as Rec. 2020.[1][2]
Luma coefficients
Rec. 2100 allows for RGB and YCbCr signal formats with 4:4:4, 4:2:2, and 4:2:0 chroma subsampling.[1] Rec. 2100 specifies that if a luma (Y') signal is made that it uses the R’G’B’ coefficients 0.2627 for red, 0.6780 for green, and 0.0593 for blue.[1]
Signal formats
Rec. 2100 defines the use of RGB and YCbCr.[1] Rec. 2100 also defines ICtCp which provides an improved color representation that is designed for high dynamic range (HDR) and wide color gamut (WCG).[1][3]
Optical Transfer functions
Rec. 2100 defines two sets of HDR optical transfer functions which are perceptual quantization (PQ) and Hybrid Log-Gamma (HLG).[1] HLG is supported in Rec. 2100 with a nominal peak luminance of 1,000 cd/m2 and a system gamma value that can be adjusted depending on background luminance.[1] For a reference viewing environment the peak luminance should be 1,000 cd/m2 or more and the black level should be 0.005 cd/m2 or less.[1] The surround light should be 5 cd/m2 and be neutral grey at standard illuminant D65.[1]
Within each set, the documented transfer functions include an:
- electro-optical transfer function (EOTF) which maps the non-linear signal value into display light
- opto-optical transfer function (OOTF) which maps relative scene linear light to display linear light
- opto-electronic transfer function (OETF) which maps relative scene linear light into the non-linear signal value
See also
- Rec. 2020 - ITU-R Recommendation for UHDTV
References
- 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 "BT.2100-0 : Image parameter values for high dynamic range television for use in production and international programme exchange". International Telecommunication Union. 2016-07-04. Retrieved 2016-07-04.
- 1 2 3 4 "ITU announces BT.2100 HDR TV standard". Rasmus Larsen. 2016-07-05. Retrieved 2016-07-26.
- ↑ "ICtCp Dolby White Paper" (PDF). Dolby. Retrieved 2016-04-20.