1、BRITISH STANDARDBS EN 61966-2-4:2006Multimedia systems and equipment Colour measurement and management Part 24: Colour management Extended-gamut YCC colour space for video applications xvYCCThe European Standard EN 61966-2-4:2006 has the status of a British StandardICS 33.160.40 g49g50g3g38g50g51g60
2、g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58Licensed Copy: Wang Bin, na, Wed Feb 07 01:43:25 GMT+00:00 2007, Uncontrolled Copy, (c) BSIBS EN 61966-2-4:2006This Brit
3、ish Standard was published under the authority of the Standards Policy and Strategy Committee on 31 October 2006 BSI 2006ISBN 0 580 49415 2National forewordThis British Standard was published by BSI. It is the UK implementation of EN 61966-2-4:2006. It is identical with IEC 61966-2-4:2006.The UK par
4、ticipation in its preparation was entrusted to Technical Committee EPL/100, Audio, video and multimedia systems and equipment.A list of organizations represented on EPL/100 can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a cont
5、ract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.Amendments issued since publicationAmd. No. Date CommentsLicensed Copy: Wang Bin, na, Wed Feb 07 01:43:25 GMT+00:00 2007, Uncontrolled Copy, (c) BSIEUROPEAN STANDA
6、RD EN 61966-2-4 NORME EUROPENNE EUROPISCHE NORM September 2006 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B - 1050 Brussels 2006 CENELEC - Al
7、l rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 61966-2-4:2006 E ICS 33.160.40 English version Multimedia systems and equipment - Colour measurement and management Part 2-4: Colour management - Extended-gamut YCC colour space for video applic
8、ations - xvYCC (IEC 61966-2-4:2006) Mesure et gestion de la couleur dans les systmes et appareils multimediaPartie 2-4 : Gestion de la couleur - Extension de gamme de lespace chromatique YCC pour applications vido - xvYCC (CEI 61966-2-4:2006) Multimediasysteme und -gerte - Farbmessung und Farbmanage
9、ment Teil 2-4: Farbmanagement - Erweiterter YCC-Farbraum fr Videoanwendungen - xvYCC (IEC 61966-2-4:2006) This European Standard was approved by CENELEC on 2006-09-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this Europea
10、n Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CENELEC member. This European Standard exists in two official versions (English
11、and German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions. CENELEC members are the national electrotechnical committees of Austria, Belgium,
12、Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Licensed Copy: Wang Bin,
13、na, Wed Feb 07 01:43:25 GMT+00:00 2007, Uncontrolled Copy, (c) BSIForeword The text of the International Standard IEC 61966-2-4:2006, prepared by IEC TC 100, Audio, video and multimedia systems and equipment, was submitted to the formal vote and was approved by CENELEC as EN 61966-2-4 on 2006-09-01
14、without any modification. The following dates were fixed: latest date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2007-06-01 latest date by which the national standards conflicting with the EN have to be withdrawn (
15、dow) 2009-09-01 _ Endorsement notice The text of the International Standard IEC 61966-2-4:2006 was approved by CENELEC as a European Standard without any modification. In the official version, for Bibliography, the following notes have to be added for the standards indicated: IEC 61966-2-1 + A1 NOTE
16、 Harmonized as EN 61966-2-1:2000 + A1:2003 (not modified). IEC 61966-2-2 NOTE Harmonized as EN 61966-2-2:2003 (not modified). _ EN 61966-2-4:2006 2 Licensed Copy: Wang Bin, na, Wed Feb 07 01:43:25 GMT+00:00 2007, Uncontrolled Copy, (c) BSIINTERNATIONAL STANDARD IEC61966-2-4First edition2006-01Multim
17、edia systems and equipment Colour measurement and management Part 2-4: Colour management Extended-gamut YCC colour space for video applications xvYCC Reference number IEC 61966-2-4:2006(E) Licensed Copy: Wang Bin, na, Wed Feb 07 01:43:25 GMT+00:00 2007, Uncontrolled Copy, (c) BSICONTENTS INTRODUCTIO
18、N.5 1 Scope.6 2 Normative references .6 3 Terms and definitions.6 4 Colorimetric parameters and related characteristics .7 4.1 Primary colours and reference white7 4.2 Opto-electronic transfer characteristics .7 4.3 YCC (luma-chroma-chroma) encoding methods.8 4.4 Digital quantization methods .8 5 En
19、coding transformations .9 5.1 Introduction .9 5.2 Transformation from xvYCC values to CIE 1931 XYZ values .9 5.3 Transformation from CIE 1931 XYZ values to xvYCC values .11 Annex A (informative) Compression of specular components of Y signals .13 Annex B (informative) Default transformation from 16-
20、bit scRGB values to xvYCC values14 Annex C (informative) xvYCC/ITU-R BT.709 and sYCC/sRGB compatibility .16 Bibliography18 Figure A.1 Example of the specular compression method 13 Figure C.1 Relationship between ITU-R BT.709 and sRGB 16 Figure C.2 Relationship between xvYCC and sYCC .17 Table 1 CIE
21、chromaticities for reference primary colours and reference white7 . EN 61966-2-4:2006 4 Annex ZA (normative) Normative references to international publications with their corresponding European publications.19 Licensed Copy: Wang Bin, na, Wed Feb 07 01:43:25 GMT+00:00 2007, Uncontrolled Copy, (c) BS
22、IINTRODUCTION After the publication of IEC 61966-2-1, Amendment 1, the sYCC colour encoding was used to capture, store and print extended colour gamut for still image applications. Users received pleasant benefit by exchanging and reproducing wide-gamut colour images. Recently, various kinds of disp
23、lays that are capable of producing a wider gamut of colour than the conventional CRT-based displays are emerging. However, most of the current video contents that are displayed on conventional displays, are rendered for the sRGB-gamut. Users of wide-gamut displays could benefit from wide-gamut colou
24、r images by video colour encoding that supports a larger colour gamut. This standard defines the “extended-gamut YCC colour space for video applications”. It is based on the current implementation of YCC colour encoding that is used in the video industry (namely ITU-R BT.709-5) and extends its defin
25、ition to the wider gamut of colour range. EN 61966-2-4:2006 5 Licensed Copy: Wang Bin, na, Wed Feb 07 01:43:25 GMT+00:00 2007, Uncontrolled Copy, (c) BSIMULTIMEDIA SYSTEMS AND EQUIPMENT COLOUR MEASUREMENT AND MANAGEMENT Part 2-4: Colour management Extended-gamut YCC colour space for video applicatio
26、ns xvYCC 1 Scope This part of IEC 61966 is applicable to the encoding and communication of YCC colours used in video systems and similar applications by defining encoding transformations for use in defined reference capturing conditions. If actual conditions differ from the reference conditions, add
27、itional rendering transformations may be required. Such additional rendering trans-formations are beyond the scope of this standard. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies.
28、 For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60050-845:1987, International Electrotechnical Vocabulary (IEV) Part 845: Lighting ITU-R Recommendation BT.601-5:1995, Studio encoding parameters of digital television for standard 4:3 and
29、wide-screen 16:9 aspect ratios ITU-R Recommendation BT.709-5:2002, Parameter values for the HDTV standards for production and international programme exchange 3 Terms and definitions For the purposes of this document, the following terms and definitions, as well as those concerning illuminance, lumi
30、nance, tristimulus, and other related lighting terms given in IEC 60050-845, apply. 3.1 scene-referred colour encoding representation of estimated colour-space coordinates of the elements of an original scene, where a scene is defined to be the relative spectral radiance 3.2 output-referred colour e
31、ncoding representation of estimated colour-space coordinates of image data that are appropriate for specified output device and viewing conditions 3.3 extended gamut colour gamut extending outside that of the standard sRGB CRT display defined in IEC 61966-2-1 EN 61966-2-4:2006 6 Licensed Copy: Wang
32、Bin, na, Wed Feb 07 01:43:25 GMT+00:00 2007, Uncontrolled Copy, (c) BSI3.4 luma luminance signal as defined by SMPTE/EG28:1993 NOTE 1 To avoid interdisciplinary confusion resulting from the two distinct definitions of luminance, it has been proposed that the video documents use “luma” for “luminance
33、, television” (i.e., the luminance signal). NOTE 2 Video systems approximate the lightness response of vision by computing a luma component Y as a weighted sum of non-linear (or gamma-corrected) RGB primary components. Luma is often carelessly referred to as luminance. 4 Colorimetric parameters and
34、related characteristics This clause defines colorimetric parameters and the related characteristics of reference capturing devices. 4.1 Primary colours and reference white The CIE chromaticities for the reference red, green, and blue primary colours, and for reference white CIE standard illuminant D
35、65, are given in Table 1. These primaries and white point values are identical to those of ITU-R BT.709-5. Table 1 CIE chromaticities for reference primary colours and reference white Red Green Blue White/D65 x 0,640 0 0,300 0 0,150 0 0,312 7 y 0,330 0 0,600 0 0,060 0 0,329 0 z 0,030 0 0,100 0 0,790
36、 0 0,358 3 4.2 Opto-electronic transfer characteristics Opto-electronic transfer characteristics are defined as follows. If 0180, ,BGR , ()()() 099,0099,1099,0099,1099,0099,145,045,045,0+=+=+=BBGGRR(1) If 0180,0180 ,BGR, 8) representation: () ()8)(xvYCC8)(xvYCC8)(xvYCC2128224round2128224round216219r
37、ound+=+=+=nNnNnNrCCrbCCbYY(7) NOTE Bit levels “from 0 to 2N-8 -1” and “from 254 x 2N-8 + 1 to 2N -1” (0 and 255, in the case of 8-bit encoding) are used exclusively for synchronization and are not allowed for storing colour values. Levels from “2N-8” to “254 x 2N-8” (from 1 to 254, in the case of 8-
38、bit encoding) are available. EN 61966-2-4:2006 8 Licensed Copy: Wang Bin, na, Wed Feb 07 01:43:25 GMT+00:00 2007, Uncontrolled Copy, (c) BSI5 Encoding transformations 5.1 Introduction The encoding transformations between xvYCC values and CIE 1931 XYZ values provide unambiguous methods to represent o
39、ptimum image colorimetry of the captured scene. Scene colorimetry is defined as relative to the white objects, assuming that the exposure is properly controlled. It should be noted that dynamic range compression is needed when storing the wide dynamic range images (see Annex A for descriptions). Add
40、itionally, if the condition of the capturing device deviates from the ideal condition defined in Clause 4, operations such as colour compensation, colour correction and a certain degree of colour rendering can be performed. However, the methods for these operations are beyond the scope of this stand
41、ard. 5.2 Transformation from xvYCC values to CIE 1931 XYZ values For 24-bit encoding (8-bit/channel), the relationship between 8-bit values and rCbCY , is defined as: ( )()22412822412821916)8(xvYCC)8(xvYCC)8(xvYCC=CrrCCbbCYY(8) For N-bit/channel ( 8N ) encoding, the relationship between N-bit values
42、 and rCbCY , is defined as: 224128222412822191628)(xvYCC8)(xvYCC8)(xvYCC=NNNNNNCrrCCbbCYY(9) For xvYCC601encoding, the non-linear rCbCY , values are transformed to the non-linear BGR , values as follows: =601601601000000772100001171401344000001040210000000001rCbCY, , , , , , ,BGR(10) NOTE The possib
43、le range for non-linear RGB(601)calculated from, for example, equation (10) will be between -1,0732 and 2,0835. For xvYCC709encoding, the non-linear rCbCY , values are transformed to the non-linear BGR , values as follows: =709709709000006855100001146803187000001857410000000001rCbCY, , , , , , ,BGR(
44、11) NOTE The possible range for non-linear RGB(709)calculated from, for example, equation (11) will be between -1,1206 and 2,1305. EN 61966-2-4:2006 9 Licensed Copy: Wang Bin, na, Wed Feb 07 01:43:25 GMT+00:00 2007, Uncontrolled Copy, (c) BSIThe non-linear BGR , values are then transformed to linear
45、 BGR , values as follows. If ,BGR 0810, , 45,0145,0145,01099,1099,0099,1099,0099,1099,0 += += +=BBGGRR(14) The linear BGR , values are transformed to CIE 1931 XYZ values as follows: =BGR, , , , , , ,ZYX595002119030190207202715062120518006357044120(15) NOTE When the capturing device performs dynamic
46、range compression of the brighter-than-white (for example, specular) components, the compressed colours will be displayed at the top-end range of the “reference“ display as described in Annex C. In this case, the XYZ tristimulus values of the compressed components represent the colorimetry of the re
47、ndered scene, not the colorimetry of the original scene. EN 61966-2-4:2006 10 Licensed Copy: Wang Bin, na, Wed Feb 07 01:43:25 GMT+00:00 2007, Uncontrolled Copy, (c) BSI5.3 Transformation from CIE 1931 XYZ values to xvYCC values The CIE 1931 XYZ values can be transformed to linear BGR , values as fo
48、llows: =ZYX, , , , , , ,BGR005710204060550604100876129690649804537102413(16) In the xvYCC encoding process, negative RGB tristimulus values and RGB tristimulus values greater than 1,0 are retained. The linear BGR , values are then transformed to non-linear BGR , values as follows. If 0180, ,BGR , ()()() 099,0099,1099,0099,1099,0099,145,045,045,0+=+=+=BBGGRR(17) If 0180,0180 ,BGR, N ) encoding, the relationship is defined as: () ()8)(xvYCC8)(xvYCC8)(xvYCC2128224round2128224round2
