1、 Recommendation ITU-R BT.2100-1 (06/2017) Image parameter values for high dynamic range television for use in production and international programme exchange BT Series Broadcasting service (television) ii Rec. ITU-R BT.2100-1 Foreword The role of the Radiocommunication Sector is to ensure the ration
2、al, equitable, efficient and economical use of the radio-frequency spectrum by all radiocommunication services, including satellite services, and carry out studies without limit of frequency range on the basis of which Recommendations are adopted. The regulatory and policy functions of the Radiocomm
3、unication Sector are performed by World and Regional Radiocommunication Conferences and Radiocommunication Assemblies supported by Study Groups. Policy on Intellectual Property Right (IPR) ITU-R policy on IPR is described in the Common Patent Policy for ITU-T/ITU-R/ISO/IEC referenced in Annex 1 of R
4、esolution ITU-R 1. Forms to be used for the submission of patent statements and licensing declarations by patent holders are available from http:/www.itu.int/ITU-R/go/patents/en where the Guidelines for Implementation of the Common Patent Policy for ITU-T/ITU-R/ISO/IEC and the ITU-R patent informati
5、on database can also be found. Series of ITU-R Recommendations (Also available online at http:/www.itu.int/publ/R-REC/en) Series Title BO Satellite delivery BR Recording for production, archival and play-out; film for television BS Broadcasting service (sound) BT Broadcasting service (television) F
6、Fixed service M Mobile, radiodetermination, amateur and related satellite services P Radiowave propagation RA Radio astronomy RS Remote sensing systems S Fixed-satellite service SA Space applications and meteorology SF Frequency sharing and coordination between fixed-satellite and fixed service syst
7、ems SM Spectrum management SNG Satellite news gathering TF Time signals and frequency standards emissions V Vocabulary and related subjects Note: This ITU-R Recommendation was approved in English under the procedure detailed in Resolution ITU-R 1. Electronic Publication Geneva, 2017 ITU 2017 All rig
8、hts reserved. No part of this publication may be reproduced, by any means whatsoever, without written permission of ITU. Rec. ITU-R BT.2100-1 1 RECOMMENDATION ITU-R BT.2100-11 Image parameter values for high dynamic range television for use in production and international programme exchange (2016-20
9、17) Scope High Dynamic Range Television (HDR-TV) provides viewers with an enhanced visual experience by providing images that have been produced to look correct on brighter displays, that provide much brighter highlights, and that provide improved detail in dark areas. This Recommendation specifies
10、HDR-TV image parameters for use in production and international programme exchange using the Perceptual Quantization (PQ) and Hybrid Log-Gamma (HLG) methods. Keywords High dynamic range, HDR, television, HDR-TV, image system parameters, television production, international programme exchange, wide c
11、olour gamut, perceptual quantization, PQ, hybrid log-gamma, HLG The ITU Radiocommunication Assembly, considering a) that digital television image formats for HDTV and UHDTV have been specified by the ITU-R in Recommendations ITU-R BT.709 and ITU-R BT.2020; b) that these television image formats have
12、 been limited in the image dynamic range they can provide due to their reliance on legacy cathode ray tube (CRT) characteristics that limit image brightness and detail in dark areas; c) that modern displays are capable of reproducing images at a higher luminance, greater contrast ratio and wider col
13、our gamut than is conventionally employed in programme production; d) that viewers expect future television viewing to provide improved characteristics compared with the current HDTV and UHDTV in terms of a more realistic sensation, greater transparency to the real world and more accurate visual inf
14、ormation; e) that high dynamic range television (HDR-TV) has been shown to increase viewer enjoyment of television pictures; f) that HDR-TV provides a “step-change” improvement in viewer experience by means of substantially increased brightness and detail in highlights and diffuse reflecting objects
15、, while providing greater detail in dark areas; g) that the combination of extended dynamic range and extended colour gamut give HDR-TV a substantially larger colour volume; h) that the HDR-TV image formats should have, where appropriate, a degree of compatibility with existing workflows and infrast
16、ructure; 1 Revisions to parameter values within this document should be compared to those in the previously published version of this Recommendation. 2 Rec. ITU-R BT.2100-1 i) that a reference viewing environment including display parameters should be defined for HDR-TV image formats, further consid
17、ering that due to rapid developments in HDR technology the ITU may wish to consider early updates and improvements to this Recommendation, recognizing that Report ITU-R BT.2390 contains much information on two methods to achieve HDR-TV, recommends that for programme production and international exch
18、ange of HDR-TV, the perceptual quantization (PQ) or Hybrid Log-Gamma (HLG) specifications described in this Recommendation should be used. NOTE The PQ specification achieves a very wide range of brightness levels for a given bit depth using a non-linear transfer function that is finely tuned to matc
19、h the human visual system. The HLG specification offers a degree of compatibility with legacy displays by more closely matching the previously established television transfer curves. Report ITU-R BT.2390 provides additional information on PQ and HLG, conversion between them, and compatibility with p
20、revious systems. TABLE 1 Image spatial and temporal characteristics Parameter Values Image Container 1a Shape 16:9 Container Pixel count 1b Horizontal Vertical 7 680 4 320 3 840 2 160 1 920 1 080 Sampling lattice Orthogonal Pixel aspect ratio 1:1 (square pixels) Pixel addressing Pixel ordering in ea
21、ch row is from left to right, and rows are ordered from top to bottom. Frame frequency (Hz) 120, 120/1.001,100, 60, 60/1.001, 50, 30, 30/1.001, 25, 24, 24/1.001 Image Format Progressive NOTE 1a Container is used to define the horizontal and vertical constraints of the image format. NOTE 1b Productio
22、ns should use the highest resolution image format that is practical. It is recognized that in many cases high resolution productions will be down-sampled to lower resolution formats for distribution. It is known that producing in a higher resolution format, and then electronically down-sampling for
23、distribution, yields superior quality than producing at the resolution used for distribution. Rec. ITU-R BT.2100-1 3 TABLE 2 System colorimetry Parameter Values Optical spectrum (informative) Chromaticity coordinates (CIE, 1931) x y Primary colours Red primary (R) monochromatic 630 nm 0.708 0.292 Gr
24、een primary (G) monochromatic 532 nm 0.170 0.797 Blue primary (B) monochromatic 467 nm 0.131 0.046 Reference white D65 per ISO 11664-2:2007 0.3127 0.3290 Colour Matching Functions CIE 1931 Table 3 specifies parameters to establish a reference viewing environment for critical viewing of HDR programme
25、 material or completed programmes that can provide repeatable results from one facility to another when viewing the same material. Viewing facilities can and will continue to be established in many ways by entities involved in editing, colour correction, screening and the like, and the specification
26、s in this Table are not intended to suggest a need for absolute uniformity in such facilities. TABLE 3 Reference viewing environment for critical viewing of HDR programme material Parameter Values Surround and periphery 3a Neutral grey at D65 Luminance of surround 5 cd/m2 Luminance of periphery 5 cd
27、/m2 Ambient lighting Avoid light falling on the screen Viewing distance 3b For 1 920 1 080 format: 3.2 picture heights For 3 840 2 160 format: 1.6 to 3.2 picture heights For 7 680 4 320 format: 0.8 to 3.2 picture heights Peak luminance of display 3c 1 000 cd/m2 Minimum luminance of display (black le
28、vel) 3d 0.005 cd/m2 NOTE 3a “Surround” is the area surrounding a display that can affect the adaptation of the eye, typically the wall or curtain behind the display; “periphery” is the remaining environment outside of the surround. NOTE 3b When picture evaluation involves resolution, the lower value
29、 of viewing distance should be used. When resolution is not being evaluated, any viewing distance in the indicated range may be used. NOTE 3c This is not to imply this level of luminance must be achieved for full screen white, rather for small area highlights. NOTE 3d The actual black level would be
30、 set using a “PLUGE” signal (under development) and may differ from the indicated value. 4 Rec. ITU-R BT.2100-1 Tables 4 and 5 describe transfer functions for the PQ and HLG formats, respectively. High dynamic range television production and display should make consistent use of the transfer functio
31、ns of one system or the other and not intermix them. Informative Annex 1 illustrates the meaning of the various transfer functions and where they are used in the signal chain. Informative Annex 2 provides information on alternate equations that could facilitate implementation of these transfer funct
32、ions. TABLE 4 PQ system reference non-linear transfer functions Parameter Values Input signal to PQ electro-optical transfer function (EOTF) Non-linear PQ encoded value. The EOTF maps the non-linear PQ signal into display light. Reference PQ EOTF 4a 122 113211 0,m a x10000E O T FmmmDEcccEYYEF where:
33、 E denotes a non-linear colour value R, G, B or L, M, S in PQ space 0,1 FD is the luminance of a displayed linear component RD, GD, BD or YD or ID, in cd/m2. 4b So that when R=G=B, the displayed pixel is achromatic. Y denotes the normalized linear colour value, in the range 0:1 m1 = 2610/16384 = 0.1
34、593017578125 m2 = 2523/4096 128 = 78.84375 c1 = 3424/4096 =0.8359375 = c3 c2 + 1 c2 = 2413/4096 32 = 18.8515625 c3 = 2392/4096 32 = 18.6875 Input signal to PQ opto-optical transfer function (OOTF) Scene linear light. The OOTF maps relative scene linear light to display linear light. Reference PQ OOT
35、F FD = OOTFE = G1886 G709E where: E = RS, GS, BS; YS; or IS is the signal determined by scene light and scaled by camera exposure The values E, RS, GS, BS, YS, IS are in the range 0:1 4c E is a non-linear representation of E FD is the luminance of a displayed linear component (RD, GD, BD; YD; or ID)
36、 FD = G1886 G709E = G1886 E E = G709E = 1.099 (59.5208 E)0.45 0.099 for 1 E 0.0003024 = 267.84 E for 0.0003024 E 0 FD = G1886E = 100 E 2.4 Input signal to PQ opto-electronic transfer function (OETF) Scene linear light. The OETF maps relative scene linear light into the non-linear PQ signal value. Re
37、c. ITU-R BT.2100-1 5 TABLE 4 (end) Parameter Values Reference PQ OETF Use of this OETF will yield the reference OOTF when displayed on a reference monitor employing the reference EOTF. DFEEE 11 E O T FO O T FE O T FO E T F where 100001E O T F2113211DmmmDFYYcYccF E is the resulting non-linear signal
38、(R, G, B) in the range 0:1 FD, E, are as specified in the opto-optical transfer function m1, m2, c1, c2, c3 are as specified in the electro-optical transfer functionNOTE 4a This same non-linearity (and its inverse) should be used when it is necessary to convert between the non-linear representation
39、and the linear representations. NOTE 4b In this Recommendation, when referring to the luminance of a single colour component (RD, GD, BD), it means the luminance of an equivalent achromatic signal with all three colour components having that same value. NOTE 4c Depending on the exposure range of the
40、 camera, it may be desirable to output a smaller luminance range than can be represented by PQ. This may be achieved by scaling the raw 0-1 linear exposure range of the camera to a more limited range before applying the OOTF. TABLE 5 Hybrid Log-Gamma (HLG) system reference non-linear transfer functi
41、ons Parameter Values Input signal to HLG OETF Scene linear light. The OETF maps relative scene linear light into the non-linear signal value.HLG Reference OETF 5a 112ln 03O E T F 121 121EcbEa EEEE where: E is the signal for each colour component RS, GS, BS proportional to scene linear light and scal
42、ed by camera exposure, normalized to the range 0:1. E is the resulting non-linear signal R, G, B in the range 0:1. a = 0.17883277, ab 41 , aac 4ln5.0 5b Input signal to HLG EOTF Non-linear HLG encoded value. The EOTF maps the non-linear HLG signal into display light. 6 Rec. ITU-R BT.2100-1 TABLE 5 (
43、continued) Parameter Values HLG Reference EOTF EEF D 1O E T FO O T FO O T F Thus, 111SSDSSDSSDBYBGYGRYR where: RS, GS, BS are the scene linear light signals, E, for each colour component normalized in the range 0:1. BBWSSSSLLLBGRYEbacEEEEE 12/0593.06780.02627.0/e x p04O E T F212121 BBWSSSSLLLBGRYEba
44、cEEEEE 0593.06780.02627.0112/ e x p03/O E T F212121and: FD is the luminance of a displayed linear component RD, GD, or BD, in cd/m2. 5c RD, GD, BD are the displayed light for each colour component, in cd/m2, so that when R=G=B, the displayed pixel is achromatic. = 1.2 at the nominal display peak lum
45、inance of 1 000 cd/m2. 5d, 5e, 5f E is the non-linear signal R, G, B as defined for the OETF. 5g The values of parameters a, b, and c are as defined for the OETF. The OOTF is defined below LW is nominal peak luminance of the display in cd/m2 for achromatic pixels. LB is the display luminance for bla
46、ck in cd/m2. The nominal signal range of E, RS, GS, BS, and YS is 0:1. HLG Input signal to OOTF Scene linear light. The OOTF maps relative scene linear light to display linear light. Rec. ITU-R BT.2100-1 7 TABLE 5 (end) Parameter Values HLG Reference OOTF 5h SSSsSSDSSDSSDSDBGRYBYBGYGRYREYEF0593.0678
47、0.02627.0O O T F1111where: FD is the luminance of a displayed linear component RD, GD, or BD, in cd/m2. RD, GD, or BD are as defined for the HLG Reference EOTF. E is the signal for each colour component Rs, Gs, Bs proportional to scene linear light and scaled by camera exposure, normalized to the ra
48、nge 0:1. YS is the normalized linear scene luminance. , , and are as defined for the EOTF.NOTE 5a The inverse of this non-linearity should be used when it is necessary to convert between the non-linear representation and the linear representation of scene light. NOTE 5b The values of b and c are calculated to b = 0.28466892, c = 0.55991073. NOTE 5c In this Recommendation, when referring to the luminance of a single colour component (RD, GD, BD), it means the luminance of an equivalent achromat
