Wide Color GamutSET EXPO 2016

31 AUGUST 2016

Eliésio Silva JúniorReseller Account Manager E/ esilvaj@tek.comT/ +55 11 3530-8940 M/ +55 21 9 7242-4211 tek.com

Anatomy Human Vision

CIE Chart

Color Gamuts

Wide Color Gamut

2

Gamma and High Dynamic Range

http://webvision.med.utah.edu/index.html

• Eye, Lens and Retina

▪ Rods

▫ Sensitive to Blue-green light

▫ Used for vision under dark-dim conditions.

▪ Cones

▫ 3 Types of Cones

Sensitive to either

long wavelengths of light (red light)

medium wavelengths of light (green light)

short wavelengths of light (blue light)

◦ Optic nerve

Basic Anatomy - Human vision systemPHYSICAL PART/ELEMENTS

3

Color Model – CIE color spaces

4

BT709/sRGB(70% NTSC)~SMPTE C

BT2020

CIE-1931 chart

D65 white

NTSC(1953)

• CIE 1931 XYZ color space

◦ Still foundation of most color models

• Trichromatic stimulus (color value)

• Lightness decreases towards not shown third dimmension

• Saturation increases towards edges

CIE-1976 chart(More perceptually uniform than CIE-1931)

D65 white

BT2020

BT709/sRGB~SMPTE C

NTSC(1953)

Black

White

ITU 601-7 & 709-5 Chromaticity

601-7 525 CIE x CIE y

Red 0.630 0.340

Green 0.310 0.595

Blue 0.155 0.070

White 0.3127 0.3290

5

709-5/601 625 CIE x CIE y

Red 0.640 0.330

Green 0.300 0.600

Blue 0.150 0.060

White 0.3127 0.3290

ITU-R BT 709-5

ITU-R BT 601-7

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Wider Color - Chromaticity

6

CIE x CIE y

Red 0.708 0.292

Green 0.170 0.797

Blue 0.131 0.046

White 0.31272 0.32903

ITU-R BT 2020

709-5 CIE x CIE y

Red 0.640 0.330

Green 0.300 0.600

Blue 0.150 0.060

White 0.3127 0.3290

ITU-R BT 709-5

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Wider Color - Chromaticity

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CIE x CIE y

Red 0.73470 0.26530

Green 0.14000 0.86000

Blue 0.10000 -0.02985

White 0.31272 0.32903

CIE x CIE y

Red 0.680 0.3230

Green 0.2650 0.6900

Blue 0.150 0.06000

DCI P3 D65 0.3127 0.3290

SMPTE 2048-1 Free Scale (FS) Gamut

X’Y’Z’ Color Space EG431-2 (P3)

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ACES Color Space - Academy Color Encoding System

8

CIE x CIE y

Red 0.73470 0.26530

Green 0.00000 1.00000

Blue 0.00010 -0.07700

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Color image encoding system created

by the Academy of Motion Picture Arts

and Sciences that allows for a fully

encompassing color accurate workflow.

Wide(er) Color Gamut Percentage

BT709/sRGB(70% NTSC)~SMPTE C

BT2020

CIE-1931 chart

D65 white

NTSC(1953)

NTSC occupies 47.3% of CIE Chart 1931

709 occupies 33.5% of CIE chart 1931

DCI-P3 occupies 44.5% of CIE Chart 1931

2020 occupies 63.3% of CIE Chart 1931

9

Wide(er) Color Gamut

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Wide(er) Color Gamut Video Ecosystem

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BasebandVideo

MPEGSignal

TransportStream

• File-BasedVideo

QAM

Optical

DVB

ISDB-TB

FTP

SET TOP BOX

DISPLAY

RGB and YPbPr Color Space

• YPbPr color cube shows Parallel-Piped of RGB colors

• Certain YPbPr values when converted to RGB will fall outside the

allowed range and will be out of Gamut

12

525 RGB to SD (601) & HD (709) YPbPr

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100% Color Bars SD 525 RGB

SD 525 YPbPr HD 1080 YPbPr

HD/UHD (709) YPbPr and UHD (2020)

14

UHD (709) YPbPr

UHD (2020) YPbPr / 525

HD 1080 YPbPr

UHD (709) & (2020) YPbPr

15

4K Monitoring – ITU-R BT.2020

16

Gamut

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17

Gamut

17

18

Gamut

18

19

Gamut

19

20

Gamut

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21

Gamut

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22

Gamut

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23

Color Space

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Why does HDR look better than SDR ?

• Are HDR screens brighter on average?

• Are HDR screens darker on average with blacker blacks?

• Is the average picture level (APL) unchanged?

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Why does HDR look better than SDR

HDR RETAINS BRIGHT SPECULAR HIGHLIGHTS AS WELL AS

DETAIL IN BLACKS

WHICH CAN MAKE COLORS APPEAR MORE SATURATED.

Sky Light: >500K nitsLooking at the sun > 1 billion nits(don’t look at it)

Lap top or TV: 100 to 200 nits(hard to see in bright daylight

Shadows: .1 to 10 nitsWith day adapted eye shadowscan be 10 nits. In living room, less than 0.1 nits

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Total Visual Dynamic Range

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HDR MAPPING INTO CAMERA F-STOPS (0 STOP = 18% REFLECTANCE)

Nits (cd/m^2)

Meso

pic

Ph

oto

pic

Scoto

pic

ST.20

84

HD

R D

isplay

Son

y, AR

RI, C

ano

n~1

6-sto

ps

Pu

sh

Pu

ll

10^8

10^-6

10^6

10^4

10^2

10^0

10^-2

10^-4

(18%) 20

starlight

moonlight

indoorlighting

Sun lightoutdoor 2

4-sto

ps w

ith so

me

adap

tion

Ad

apte

d Eye

Bri

ght

adap

tio

n

Dark A

dap

tion

7-sto

ps

Sunlightoutdoor

IndoorLighting

Moonlight

Starlight

(5000 nits)8

(.08 nits) -8

6

4

2

-2

-4

(20nits) 0

-6

Stops

Ad

apte

d Eye

~7-sto

ps

Bri

ght

adap

tio

n

Dark

adap

tion

(100nits)2.5

(18%)

(90%)

Potential Issues with Bright HDR displays

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• Color shift in the Mesopic-level adaption (dark viewing environment)• As light moves below Photopic (dominated by cones) and gets closer to Scotopic (dominated by rods) color

saturation will diminish.• This may occur in dark scenes in low-light home theater.

• Light/Dark Adaption (bleaching process rather than pupil size)• Sustained bright images cause the photo-pigment in the retina to reduce and can result in the perception

of after images. • Dark adaption can take seconds or even minutes. Changes to dark scenes from bright scenes may take

more time in dark theater as opposed to same scene in higher ambient light.

• Viewing distance• Static adaption is only about 7 to 9 stops.• To take full advantage of HDR (> 9 stops) via local adaption, you have to be closer than 2 screen widths• If you do sit this close, you may get eye strain

• Large Area Flicker • Strobing of high peak light levels may cause distress to some viewers. Perceptual flicker frequency may be

increased since it is a function of retinal adaption. May contribute to PSE (BT.1702). • Frame rate judder may be more visible.

Proposed HDR Formats

• SMPTE ST.2084:2014 High Dynamic Range Electro-Optical Transfer Function of Mastering

Reference Displays

“Dolby Vision”

Perceptual Quantizer (PQ) based on Barten contour perception

EOTF is inverse of OETF allowing .001 to 10K nits with 10-bits

Current “Pulsar” display peaks at about 4K nits

• Hybrid Log-Gamma, “HLG”, from BBC/NHK (ARIB STD-B67)

Extends log processing (de-facto in many cameras) of high brightness peaks to mitigate blown-out or clipped whites

Seamless “gamma” power-law processing in blacks as in BT.709/BT.2020 but without linear segment

Displays can evolve to allow 400X to 800X increase in display

Allows display EOTF to adjust system gamma to correct for surround illumination (i.e. 10 nits to 500 nits)

2831 AUGUST 2016

Proposed HDR Formats

• Philips Parameter-based from HDR master

Embed low bit-rate HDR and SDR conversion parameters into metadata

Extract parameters during decode and tune display for peak luma

Optional Y’u’v’ encoding (more perceptually uniform)

• Technicolor Video Mastering and Distribution Workflow

Grade both an HDR and SDR master

Vital to maintain “Artistic Intent”

• Academy Color Encoding System (ACES)

(dynamic range and wide color gamut preserving workflow, not an HDR format)

33 bit floating point

10-bit proxy output in stops (log2).

2931 AUGUST 2016

Capturing a Camera RAW image

Gamma0% Black

10-bit Code-Value %18% Grey

(20 nits illumination)10-bit Code-Value

%90% Reflectance

10-bit Code-Value%

S Log 1 90 3 394 37.7 636 65

S Log 2 90 3 347 32.3 582 59

S Log 3 95 3.5 420 40.6 598 61

LogC 134 3.5 400 38.4 569 58

C-Log 128 7.3 351 32.8 614 63

ACES (proxy) ND ND 426 41.3 524 55

BT.709 64 0 423 41.0 940 100

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Camera (scene) referenced 709 to PQ LUT conversion

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0 20 40 60 80 1000

10

20

30

40

50

60

70

80

90

100

Camera-side conversion BT.709 to PQ

% or IRE

SDR_2_HDR_CS,,BT709i1001000

SDR_2_HDR_CS,,BT709i1002000

SDR_2_HDR_CS,,BT709i1005000

9 41

BT709i

Camera-Side ConversionBT.709 to PQ

BT.709 % IRE

SDR BT.709,100,1000

SDR and HDR displays DO NOT match.Blacks are stretched in the BT1886 Display but not the PQ Display (matches scene)

SDR BT.709,100,2000

SDR BT.709,100,5000

2084 HDR 0% 2% 18 % 90% 100%

709 100nits

0 9 41 95 100

HDR 1000nits 0 37 58 75 76

HDR 2000nits 0 31 51 68 68

HDR 5000nits 0 24 42 58 59

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Studio Monitor referenced 709 to PQ LUT conversion

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0 2 0 4 0 6 0 8 0 1 0 00

1 0

2 0

3 0

4 0

5 0

6 0

7 0

8 0

9 0

1 0 0

Display-side conv ersio n BT.7 09 to PQ

% o r IRE

S D R_ 2 _ H DR _ DS ,,BT 7 0 9i

1 0 0 1 0 0 0

S D R_ 2 _ H DR _ DS ,,BT 7 0 9i

1 0 0 2 0 0 0

S D R_ 2 _ H DR _ DS ,,BT 7 0 9i

1 0 0 5 0 0 0

9 4 1

BT 7 0 9i

SDR and HDR displays matchBlacks are stretched in both the BT1886 and PQ Display

Display-Side ConversionBT.709 to PQ

BT.709 % IRE

HDR BT.709,100,1000

HDR BT.709,100,2000

HDR BT.709,100,5000

2084 HDR 0% 2% 18 % 90% 100%

709 100nits

0 9 41 90 100

HDR 1000nits 0 22 52 74 75

HDR 2000nits 0 17 46 66 68

HDR 5000nits 0 13 37 57 58

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SMPTE 2084 PQ Look Up Tables

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Linear Ramp Test SignalBT.709

Look Up TableSMPTE 2084 1000nits

Reference White 100nits

Look Up TableSMPTE 2084 1000nits

Reference White 300nits

31 AUGUST 2016

Slog 2 Camera RAW to HDR

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HDR 1000 Nits90% Reflectance White 75%, 18% Grey 58%

Look Up Table Converted SLog2 to ST 2084 PQ

Need HDR Monitor to view this image.

31 AUGUST 2016

Slog 2 Camera RAW to HDR

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HDR 1000 Nits90% Reflectance White 75%, 18% Grey 58%

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Gamma

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Gamma correction, gamma nonlinearity, gamma encoding, or

simply gamma, is the name of a nonlinear operation used to code

and decode luminance in video or still image systems

31 AUGUST 2016

Colour Model

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A colour model is an abstract mathematical model describing the

way color can be represented as tuples of numbers, typically as

three or four value or color components ( e.g RGB are CMYK are

color models)

31 AUGUST 2016

Gamut

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In color reproduction, including computer graphics and

photography, the gamut, or color gamut, is a certain complete

subset of colors.

The most common usage refers to the subset of colors which can

be accurately represented in a given circumstance, such as within

a given color space or by a certain output device.

31 AUGUST 2016

Colour Space

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Color space is a more specific term for a certain combination of a

color model plus a mapping function, the term “color space” tends

to be used to also identify color models, since identify a color

space automatically identifies the associated color model.

Gamut + Colour Model = Colour Space

31 AUGUST 2016

Summary

• Camera’s today are able to capture a wide dynamic range

• SDR displays typically clip or blow out the highlights of the image

• The use of non-linear processing such as S-Log 2, ST 2084 PQ

and HLG use the bits more efficiently to capture the image

• Overall this allows HDR displays to utilize the bits more effectively

• White point and 18% grey levels need to be set correctly using a

waveform monitor to simplify the process

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GAMMA AND HIGH DYNAMIC RANGE

31 AUGUST 2016

Thank you very much

See you at booth 33

Eliésio Silva Júnior

Reseller Account Manager

E/ esilvaj@tek.com

M/ + 55 21 9 7242-4211