ITURBT.210022018用于制作和国际节目交换的高动态范围电视的图像参数值

RecommendationITU-RBT.2100-2

(07/2018)

Imageparametervaluesforhighdynamicrangetelevisionforuseinproductionandinternationalprogrammeexchange

BTSeriesBroadcastingservice

(television)

ii

Rec.ITU-RBT.2100-2

Rec.ITU-RBT.2100-2

PAGE

11

Foreword

TheroleoftheRadiocommunicationSectoristoensuretherational,equitable,efficientandeconomicaluseoftheradio-frequencyspectrumbyallradiocommunicationservices,includingsatelliteservices,andcarryoutstudieswithoutlimitoffrequencyrangeonthebasisofwhichRecommendationsareadopted.

TheregulatoryandpolicyfunctionsoftheRadiocommunicationSectorareperformedbyWorldandRegionalRadiocommunicationConferencesandRadiocommunicationAssembliessupportedbyStudyGroups.

PolicyonIntellectualPropertyRight(IPR)

ITU-RpolicyonIPRisdescribedintheCommonPatentPolicyforITU-T/ITU-R/ISO/IECreferencedinResolutionITU-R1.Formstobeusedforthesubmissionofpatentstatementsandlicensingdeclarationsbypatentholdersareavailablefrom

/ITU-R/go/patents/en

wheretheGuidelinesforImplementationoftheCommonPatentPolicyforITU-T/ITU-R/ISO/IECandtheITU-Rpatentinformationdatabasecanalsobefound.

SeriesofITU-RRecommendations

(Alsoavailableonlineat

/publ/R-REC/en

)

Series

Title

BO

Satellitedelivery

BR

Recordingforproduction,archivalandplay-out;filmfortelevision

BS

Broadcastingservice(sound)

BT

Broadcastingservice(television)

F

Fixedservice

M

Mobile,radiodetermination,amateurandrelatedsatelliteservices

P

Radiowavepropagation

RA

Radioastronomy

RS

Remotesensingsystems

S

Fixed-satelliteservice

SA

Spaceapplicationsandmeteorology

SF

Frequencysharingandcoordinationbetweenfixed-satelliteandfixedservicesystems

SM

Spectrummanagement

SNG

Satellitenewsgathering

TF

Timesignalsandfrequencystandardsemissions

V

Vocabularyandrelatedsubjects

Note:ThisITU-RRecommendationwasapprovedinEnglishundertheproceduredetailedinResolutionITU-R1.

ElectronicPublication

Geneva,2018

ITU2018

Allrightsreserved.Nopartofthispublicationmaybereproduced,byanymeanswhatsoever,withoutwrittenpermissionofITU.

RECOMMENDATIONITU-RBT.2100-2

Imageparametervaluesforhighdynamicrangetelevisionforuseinproductionandinternationalprogrammeexchange1

QuestionITU-R142-2/6

(2016-2017-2018)

TABLEOFCONTENTS

Page

Annex1(informative)–TherelationshipbetweentheOETF,theEOTFandtheOOTF 11

Annex 2 (informative) – Parametric representation of electro-optical and

opto-electronictransferfunctions 13

Scope

HighDynamicRangeTelevision(HDR-TV)providesviewerswithanenhancedvisualexperiencebyprovidingimagesthathavebeenproducedtolookcorrectonbrighterdisplays,thatprovidemuchbrighterhighlights,andthatprovideimproveddetailindarkareas.ThisRecommendationspecifiesHDR-TVimageparametersforuseinproductionandinternationalprogrammeexchangeusingthePerceptualQuantization(PQ)andHybridLog-Gamma(HLG)methods.

Keywords

Highdynamicrange,HDR,television,HDR-TV,imagesystemparameters,televisionproduction,internationalprogrammeexchange,widecolourgamut,perceptualquantization,PQ,hybridlog-gamma,HLG

TheITURadiocommunicationAssembly,

considering

thatdigitaltelevisionimageformatsforHDTVandUHDTVhavebeenspecifiedbytheITU-RinRecommendationsITU-RBT.709andITU-RBT.2020;

thatthesetelevisionimageformatshavebeenlimitedintheimagedynamicrangetheycanprovideduetotheirrelianceonlegacycathoderaytube(CRT)characteristicsthatlimitimagebrightnessanddetailindarkareas;

RadiocommunicationStudyGroup6madeeditorialamendmentstothisRecommendationintheyears2018,2019and2020inaccordancewithResolutionITU-R1.

1RevisionstoparametervalueswithinthisdocumentshouldbecomparedtothoseinthepreviouslypublishedversionofthisRecommendation.

PAGE

10

Rec.ITU-RBT.2100-2

Rec.ITU-RBT.2100-2

PAGE

3

thatmoderndisplaysarecapableofreproducingimagesatahigherluminance,greatercontrastratioandwidercolourgamutthanisconventionallyemployedinprogrammeproduction;

thatviewersexpectfuturetelevisionviewingtoprovideimprovedcharacteristicscomparedwiththecurrentHDTVandUHDTVintermsofamorerealisticsensation,greatertransparencytotherealworldandmoreaccuratevisualinformation;

thathighdynamicrangetelevision(HDR-TV)hasbeenshowntoincreaseviewerenjoymentoftelevisionpictures;

thatHDR-TVprovidesa“step-change”improvementinviewerexperiencebymeansofsubstantiallyincreasedbrightnessanddetailinhighlightsanddiffusereflectingobjects,whileprovidinggreaterdetailindarkareas;

thatthecombinationofextendeddynamicrangeandextendedcolourgamutgiveHDR-TVasubstantiallylargercolourvolume;

thattheHDR-TVimageformatsshouldhave,whereappropriate,adegreeofcompatibilitywithexistingworkflowsandinfrastructure;

thatareferenceviewingenvironmentincludingdisplayparametersshouldbedefinedforHDR-TVimageformats,

furtherconsidering

thatduetorapiddevelopmentsinHDRtechnologytheITUmaywishtoconsiderearlyupdatesandimprovementstothisRecommendation,

recognizing

thatReportITU-RBT.2390containsmuchinformationontwomethodstoachieveHDR-TV,

recommends

thatforprogrammeproductionandinternationalexchangeofHDR-TV,theperceptualquantization(PQ)orHybridLog-Gamma(HLG)specificationsdescribedinthisRecommendationshouldbeused.

NOTE–ThePQspecificationachievesaverywiderangeofbrightnesslevelsforagivenbitdepthusinganon-lineartransferfunctionthatisfinelytunedtomatchthehumanvisualsystem.TheHLGspecificationoffersadegreeofcompatibilitywithlegacydisplaysbymorecloselymatchingthepreviouslyestablishedtelevisiontransfercurves.ReportITU-RBT.2390providesadditionalinformationonPQandHLG,conversionbetweenthem,andcompatibilitywithprevioussystems.

TABLE1

Imagespatialandtemporalcharacteristics

Parameter

Values

ImageContainer1aShape

16:9

ContainerPixelcount1b

Horizontal×Vertical

7680×4320

3840×2160

1920×1080

Samplinglattice

Orthogonal

Pixelaspectratio

1:1(squarepixels)

Pixeladdressing

Pixelorderingineachrowisfromlefttoright,androwsareorderedfromtoptobottom.

Framefrequency(Hz)

120,120/1.001,100,60,60/1.001,50,30,30/1.001,25,24,24/1.001

ImageFormat

Progressive

Note1a–Containerisusedtodefinethehorizontalandverticalconstraintsoftheimageformat.

Note1b–Productionsshouldusethehighestresolutionimageformatthatispractical.Itisrecognizedthatinmanycaseshighresolutionproductionswillbedown-sampledtolowerresolutionformatsfordistribution.Itisknownthatproducinginahigherresolutionformat,andthenelectronicallydown-samplingfordistribution,yieldssuperiorqualitythanproducingattheresolutionusedfordistribution.

TABLE2

Systemcolorimetry

Parameter

Values

Opticalspectrum(informative)

Chromaticitycoordinates(CIE,1931)

x

y

Primarycolours

Redprimary(R)

monochromatic630nm

0.708

0.292

Greenprimary(G)

monochromatic532nm

0.170

0.797

Blueprimary(B)

monochromatic467nm

0.131

0.046

Referencewhite

D65per

ISO11664-2:2007

0.3127

0.3290

ColourMatchingFunctions

CIE1931

Table3specifiesparameterstoestablishareferenceviewingenvironmentforcriticalviewingofHDRprogrammematerialorcompletedprogrammesthatcanproviderepeatableresultsfromonefacilitytoanotherwhenviewingthesamematerial.Viewingfacilitiescanandwillcontinuetobeestablishedinmanywaysbyentitiesinvolvedinediting,colourcorrection,screeningandthelike,andthespecificationsinthisTablearenotintendedtosuggestaneedforabsoluteuniformityinsuchfacilities.

TABLE3

ReferenceviewingenvironmentforcriticalviewingofHDRprogrammematerial

Parameter

Values

Surroundandperiphery3a

NeutralgreyatD65

Luminanceofsurround

5cd/m2

Luminanceofperiphery

≤5cd/m2

Ambientlighting

Avoidlightfallingonthescreen

Viewingdistance3b

For1920×1080format:3.2pictureheights

For3840×2160format:1.6to3.2pictureheights

For7680×4320format:0.8to3.2pictureheights

Peakluminanceofdisplay3c

≥1000cd/m2

Minimum luminance ofdisplay(blacklevel)3d

≤0.005cd/m2

Note3a–“Surround”istheareasurroundingadisplaythatcanaffecttheadaptationoftheeye,typicallythewallorcurtainbehindthedisplay;“periphery”istheremainingenvironmentoutsideofthesurround.

Note3b–Whenpictureevaluationinvolvesresolution,thelowervalueofviewingdistanceshouldbeused.Whenresolutionisnotbeingevaluated,anyviewingdistanceintheindicatedrangemaybeused.

Note3c–Thisisnottoimplythislevelofluminancemustbeachievedforfullscreenwhite,ratherforsmallareahighlights.

Note3d–ForPQinanon-referenceviewingenvironment,orforHLG(inanyviewingenvironment),theblacklevelshouldbeadjustedusingthePLUGEtestsignalandprocedurespecifiedinRecommendationITU-RBT.814.

Tables4and5describetransferfunctionsforthePQandHLGformats,respectively.Highdynamicrangetelevisionproductionanddisplayshouldmakeconsistentuseofthetransferfunctionsofonesystemortheotherandnotintermixthem.InformativeAnnex1illustratesthemeaningofthevarioustransferfunctionsandwheretheyareusedinthesignalchain.InformativeAnnex2providesinformationonalternateequationsthatcouldfacilitateimplementationofthesetransferfunctions.

TABLE4

PQsystemreferencenon-lineartransferfunctions

Parameter

Values

InputsignaltoPQelectro-opticaltransferfunction(EOTF)

Non-linearPQencodedvalue.

TheEOTFmapsthenon-linearPQsignalintodisplaylight.

ReferencePQEOTF4a

FDEOTFE10000Y

maxE1m2c,01m1

Y 1

ccE1m2

2 3

where:

E'denotesanon-linearcolourvalue{R',G',B'}or{L',M',S'}inPQspaceintherange[0:1]

FDistheluminanceofadisplayedlinearcomponent{RD,GD,BD}orYDor

ID,incd/m2.4b

Ydenotesthenormalizedlinearcolourvalue,intherange[0:1]

m1=2610/16384=0.1593017578125

m2=2523/4096128=78.84375

c1=3424/4096=0.8359375=c3−c2+1

c2=2413/409632=18.8515625

c3=2392/409632=18.6875

InputsignaltoPQopto-opticaltransferfunction(OOTF)

Scenelinearlight.

TheOOTFmapsrelativescenelinearlighttodisplaylinearlight.

ReferencePQOOTF

FD=OOTF[E]=G1886[G709[E]]

where:

E={RS,GS,BS;YS;orIS}isthesignaldeterminedbyscenelightandscaledbycameraexposure

ThevaluesE,RS,GS,BS,YS,ISareintherange[0:1]4c

E′isanon-linearrepresentationofE

FDistheluminanceofadisplayedlinearcomponent(RD,GD,BD;YD;orID)FD=G1886[G709[E]]=G1886E′

E′=G709[E]=1.099(59.5208E)0.45–0.099for1>E>0.0003024

=267.84E for0.0003024≥E≥0

FD=G1886[E']=100E′2.4

InputsignaltoPQopto-electronictransferfunction(OETF)

Scenelinearlight.

TheOETFmapsrelativescenelinearlightintothenon-linearPQsignalvalue.

TABLE4(end)

Parameter

Values

ReferencePQOETF

UseofthisOETFwillyieldthereferenceOOTFwhendisplayedonareferencemonitoremployingthereferenceEOTF.

EOETFEEOTF1OOTFEEOTF1F

D

where

ccYm1m2

EOTF1F1 2

D 1cYm1

3

YFD10000

E′istheresultingnon-linearsignal(R',G',B')intherange[0:1]

FD,E,areasspecifiedintheopto-opticaltransferfunction

m1,m2,c1,c2,c3areasspecifiedintheelectro-opticaltransferfunction.

Note4a–Thissamenon-linearity(anditsinverse)shouldbeusedwhenitisnecessarytoconvertbetweenthenon-linearrepresentationandthelinearrepresentations.

Note4b–InthisRecommendation,whenreferringtotheluminanceofasinglecolourcomponent(RD,GD,BD),itmeanstheluminanceofanequivalentachromaticsignalwithallthreecolourcomponentshavingthatsamevalue.

Note4c–ThemappingofthecamerasensorsignaloutputtoEmaybechosentoachievethedesiredbrightnessofthescene.

TABLE5

HybridLog-Gamma(HLG)systemreferencenon-lineartransferfunctions

Parameter

Values

InputsignaltoHLGOETF

Scenelinearlight.

TheOETFmapsrelativescenelinearlightintothenon-linearsignalvalue.

HLGReferenceOETF5a

EOETFE 3E 0E1

12

aln12Ebc 1E1

12

where:

Eisasignalforeachcolourcomponent{RS,GS,BS}proportionaltoscenelinearlightnormalizedtotherange[0:1].5b

E′istheresultingnon-linearsignal{R',G',B'}intherange[0:1].

a=0.17883277,b14a,c0.5aln4a5c

HLGInputsignaltoOOTF

Scenelinearlight.

TheOOTFmapsrelativescenelinearlighttodisplaylinearlight.

TABLE5(end)

Parameter

Values

HLGReferenceOOTF5i

FOOTFEαYγ1E

D S

RαYγ1R

D S S

GαYγ1G

D S S

BαYγ1B

D S S

Ys0.2627RS0.6780GS0.0593BS

where:

FDistheluminanceofadisplayedlinearcomponent{RD,GD,orBD},incd/m2.5d

Eisasignalforeachcolourcomponent{Rs,Gs,Bs}proportionaltoscenelinearlightnormalizedtotherange[0:1].

YSisthenormalizedlinearsceneluminance.

αisthevariableforusergainincd/m2.ItrepresentsLW,thenominalpeakluminanceofadisplayforachromaticpixels.

γisthesystemgamma.=1.2atthenominaldisplaypeakluminanceof1000cd/m2.5e,5f,5g

InputsignaltoHLGEOTF

Non-linearHLGencodedvalue.

TheEOTFmapsthenon-linearHLGsignalintodisplaylight.

HLGReferenceEOTF

FDEOTFmax0,(1)E

OOTFOETF1max0,(1)E

where:

FDistheluminanceofadisplayedlinearcomponent{RD,GD,orBD},incd/m2.

E′isthenon-linearsignal{R',G',B'}asdefinedfortheHLGReferenceOETF.5h

βisthevariableforuserblacklevellift.

OOTF[]isasdefinedfortheHLGReferenceOOTF.

1 x/3 0x12

2

OETF xexpxc/ab}/12 1x1

{ 2

Thevaluesofparametersa,b,andcareasdefinedfortheHLGReferenceOETF.

and:

3(L/L)1/

B W

LWisnominalpeakluminanceofthedisplayincd/m2forachromaticpixels.

LBisthedisplayluminanceforblackincd/m2.

NotestoTable5

Note5a–Theinverseofthisnon-linearityshouldbeusedwhenitisnecessarytoconvertbetweenthenon-linearrepresentationandthelinearrepresentationofscenelight.

Note5b–ThemappingofthecamerasensorsignaloutputtoEmaybechosentoachievethedesiredbrightnessofthescene.

Note5c–Thevaluesofbandcarecalculatedtob=0.28466892,c=0.55991073.

Note5d–InthisRecommendation,whenreferringtotheluminanceofasinglecolourcomponent(RD,GD,BD),itmeanstheluminanceofanequivalentachromaticsignalwithallthreecolourcomponentshavingthatsamevalue.

Note5e–ThisEOTFappliesgammatotheluminancecomponentofthesignal,whereassomelegacydisplaysmayapplygammaseparatelytocolourcomponents.SuchlegacydisplaysapproximatethisreferenceOOTF.

Note5f–Fordisplayswithnominalpeakluminance(LW)greaterthan1000cd/m2,orwheretheeffectivenominalpeakluminanceisreducedthroughtheuseofacontrastcontrol,thesystemgammavalueshouldbeadjustedaccordingtotheformulabelow2,andmayberoundedtothreesignificantdigits:

γ1.20.42Log10LW1000

Note5g–Thesystemgammavaluemaybedecreasedforbrighterbackgroundandsurroundconditions.

Note5h–Duringproduction,signalvaluesareexpectedtoexceedtherangeE′=[0.0:1.0].Thisprovidesprocessingheadroomandavoidssignaldegradationduringcascadedprocessing.SuchvaluesofE′,below0.0orexceeding1.0,shouldnotbeclippedduringproductionandexchange.Valuesbelow0.0shouldnotbeclippedinreferencedisplays(eventhoughtheyrepresent“negative”light)toallowtheblacklevelofthesignal(LB)tobeproperlysetusingtestsignalsknownas“PLUGE”.

Note5i–TheinverseofHLGOOTFisderivedasfollows:

Y1R

RSD D

Y1G

GSD D

Y1B

BSD D

YD0.2627RD0.6780GD0.0593BD

Forprocessingpurposes,whentheactualdisplayisnotknown,αmaybesetto1.0cd/m2.

Tables6and7describedifferentluminanceandcolourdifferencesignalrepresentations,suitableforcoloursub-sampling,and/orsourcecoding.TheNon-ConstantLuminance(NCL)formatisinwidespreaduseandisconsideredthedefault.TheConstantIntensity(CI)formatisnewlyintroducedinthisRecommendationandshouldnotbeusedforprogrammeexchangeunlessallpartiesagree.

TABLE6

Non-ConstantLuminanceY'C'BC'Rsignalformat6a

Parameter

ValuesPQ

ValuesHLG

DerivationofR',G',B'

{R',G',B'}=EOTF−1(FD)whereFD={RD,GD,BD}

{R',G',B'}=OETF(E)whereE={RS,GS,BS}

DerivationofY'

Y'=0.2627R'+0.6780G'+0.0593B'

Derivationofcolourdifferencesignals

CBB'Y'

1.8814

CRR'Y'

1.4746

Note6a–Forconsistencywithprioruseofterms,Y',C'BandC'Remployprimesymbolsindicatingtheyhavecomefromnon-linearY,BandR.

2ForapplicationsinwhichLWisoutsidetherange400cd/m2to2000cd/m2thefollowingformulamaybeused:γ=1.2∗𝜅Log2(𝐿𝑤/1000)where𝜅=1.111.

TABLE7

ConstantIntensityICTCPsignalformat7a,7b

Parameter

ValuesPQ

ValuesHLG

L,M,SColourSpace

L1688R2146G262B4096

M683R2951G462B4096

S99R309G3688B4096

DerivationofL',M',S'7c

{L',M',S'}=EOTF−1(FD)whereFD={LD,MD,SD}

{L',M',S'}=OETF(E)whereE={LS,MS,SS}

DerivationofI

I=0.5L'+0.5M'

Derivation of colourdifferencesignals

CT6610L'13613M'7003S'4096

CP17933L'17390M'543S'4096

𝐶𝑇=(3625𝐿′−7465𝑀′+3840𝑆′)/4096

𝐶𝑃=(9500𝐿′−9212𝑀′−288𝑆′)/4096

Note7a–ThenewlyintroducedI,CTandCPsymbolsdonotemploytheprimesymbolstosimplifythenotation.

Note7b–ColoursshouldbeconstrainedtobewithinthetriangledefinedbytheRGBcolourprimariesinTable2.

Note7c–ThesubscriptsDandSrefertodisplaylightandscenelight,respectively.

TABLE8

Coloursub-sampling

Parameters

Values

Codedsignal

R',G',B'orY',C'B,C'R,,orI,CT,CP

Samplinglattice–R',G',B',Y',I

Orthogonal,lineandpicturerepetitiveco-sited

Samplinglattice–C'B,C'R,CT,CP

Orthogonal,lineandpicturerepetitiveco-sitedwitheachother.Thefirst(top-left)sampleisco-sitedwiththefirstY'orIsamples.

4:4:4system

4:2:2system

4:2:0system

EachhasthesamenumberofhorizontalsamplesastheY'orIcomponent.

HorizontallysubsampledbyafactoroftwowithrespecttotheY'orIcomponent.

HorizontallyandverticallysubsampledbyafactoroftwowithrespecttotheY'orIcomponent.

Table9describestwodifferentsignalrepresentations,“narrow”and“full”.Thenarrowrangerepresentationisinwidespreaduseandisconsideredthedefault.ThefullrangerepresentationisnewlyintroducedinthisRecommendationandshouldnotbeusedforprogrammeexchangeunlessallpartiesagree.

TABLE9

Digital10-and12-bitintegerrepresentation

Parameters

Values

Codedsignal

R',G',B'orY',C'B,C'R,orI,CT,CP

Codingformat

n=10,12bitspercomponent

QuantizationofR',G',B',Y',I(resultingvaluesthatexceedthevideodatarangeshouldbeclippedtothevideodatarange)

Narrowrange

Fullrange

D=Round[(219E′+16)2n−8]

D=Round[(2n-1)E′]

QuantizationofC'B,C'R,CT,CP(resultingvaluesthatexceedthevideodatarangeshouldbeclippedtothevideodatarange)

D=Round[(224E′+128)2n−8]

D=Round[(2n-1)E′+2n-1]

Quantizationlevels

10-bitcoding

12-bitcoding

10-bitcoding

12-bitcoding

Black

(R'=G'=B'=Y'=I=0)

DR',DG',DB',DY',DI

64

256

0

0

NominalPeak

(R'=G'=B'=Y'=I=1)

DR',DG',DB',DY',DI

940

3760

1023

4095

Achromatic

(C'B=C'R=0)

DC'B,DC'R,DCT,DCP

512

2048

512

2048

NominalPeak

(C'B=C'R=+0.5)

DC'B,DC'R,DCT,DCP

960

3840

1023

4095

NominalPeak

(C'B=C'R=-0.5)

DC'B,DC'R,DCT,DCP

64

256

1

1

Videodatarange9a,9b

4through

1019

16through

4079

0through

1023

0through

4095

Where:

Round(x)=Sign(x)*Floor(|x|+0.5)

Floor(x)thelargestintegerlessthanorequaltox

1 ;

Sign(x)=0 ;

1;

x0

x0

x0

Note9a–Narrowrangesignalsmayextendbelowblack(sub-blacks)andexceedthenominalpeakvalues(super-whites),butshouldnotexceedthevideodatarange.

Note9b–Somedigitalimageinterfacesreservedigitalvalues,e.g.fortiminginformation,suchthatthepermittedvideorangeoftheseinterfacesisnarrowerthanthevideorangeofthefull-rangesignal.Themappingfromfull-rangeimagestotheseinterfacesisapplication-specific.

Table10introducesa16-bitfloatingpointsignalrepresentation.Currently,real-timeinterfacesdonotexistforthisformat.Itisexpectedthatthisformatwouldinitiallyseeusageinfile-basedworkflowsandprogrammeexchange.

TABLE10

FloatingPoint(FP)signalrepresentation

Parameter

Values

Signalrepresentation

LinearR,G,B.

Signalencoding

16-bitfloatingpointperIEEEstandard754-2008.

Normalizationfordisplay-referredsignals

R=G=B=1.0represents1.0cd/m2onthereferencedisplay.

Normalizationforscene-referredsignals

R=G=B=1.0representsthemaximumdiffusewhitelevel.

Annex1(informative)

TherelationshipbetweentheOETF,theEOTFandtheOOTF

ThisRecommendationmakesextensiveuseofthefollowingterms:

OETF:theopto-electronictransferfunction,whichconvertslinearscenelightintothevideosignal,typicallywithinacamera.

EOTF:electro-opticaltransferfunction,whichconvertsthevideosignalintothelinearlightoutputofthedisplay.

OOTF:opto-opticaltransferfunction,whichhastheroleofapplyingthe“renderingintent”.

Thesefunctionsarerelated,soonlytwoofthethreeareindependent.Givenanytwoofthemthethirdonemaybecalculated.Thissectionexplainshowtheyariseintelevisionsystemsandhowtheyarerelated.

Scenelight

OOTFreference

Referencedisplaylight

ReferenceOOTF

BT.2100-Ann1-01

Intelevisionsystemsthedisplayedlightisnotlinearlyrelatedtothelightcapturedbythecamera.Insteadanoverallnon-linearityisapplied,theOOTF.The“reference”OOTFcompensatesfordifferenceintonalperceptionbetweentheenvironmentofthecameraandthatofthedisplay.Specificationanduseofa“referenceOOTF”allowsconsistentend-to-endimagereproduction,whichisimportantinTVproduction.

Artisticadjustmentmaybemadetoenhancethepicture.ThesealtertheOOTF,whichmaythenbecalledthe“artisticOOTF”.ArtisticadjustmentmaybeappliedeitherbeforeorafterthereferenceOOTF.

Scenelight

OOTFreference

Artisticadjustments

Referencedisplaylight

Or

Scenelight

Artisticadjustments

OOTFreference

Referencedisplaylight

ArtisticOOTF

BT.2100-Ann1-02

IngeneraltheOOTFisaconcatenationoftheOETF,artisticadjustments,andtheEOTF.

Scenelight

OETF

Artisticadjustments

Displaylight

ArtisticOOTF

BT.2100-Ann1-03

EOTF

ThePQsystemwasdesignedwiththemodelshownbelow,wheretheOOTFisconsideredtobeinthecamera(orimposedintheproductionprocess).

Scenelight

Displaylight

OETF

Encoding

Decoding

Camera

Signal

Display

BT.2100-Ann1-04

EOTF

InverseEOTF

OOTF

TheHLGsystemwasdesignedwiththemodelshownbelow,wheretheOOTFisconsideredtobeinthedisplay.

Scenelight

Displaylight

EOTF

Encoding

Decoding

Camera

Signal

Display

BT.2100-Ann1-05

OOTF

InverseOETF

OETF

Onlytwoofthreenon-linearities,theOETF,theEOTF,andtheOOTF,areindependent.Infunctionalnotation(wheresubscriptsindicatethecolourco