ColorBars theory - Revision history

Chris319: /* Y,Cb,Cr [16,235] */

2020-05-07T20:35:52Z

‎Y,Cb,Cr [16,235]

Chris319: /* R,G,B [16,235] */

2020-05-07T20:22:34Z

‎R,G,B [16,235]

Chris319: /* Y,Cb,Cr [16,235] */

2020-05-07T19:38:12Z

‎Y,Cb,Cr [16,235]

Chris319: Replaced incorrect Y,Cb,Cr values with values from RP 219 section 3.2.1 Pattern 1.

2020-05-07T19:10:15Z

Replaced incorrect Y,Cb,Cr values with values from RP 219 section 3.2.1 Pattern 1.

Admin: /* the pluge using Rec.601 coefficients */

2016-03-06T15:57:31Z

‎the pluge using Rec.601 coefficients

Raffriff42: add mis-adjusted color bars image

2015-04-13T00:07:02Z

add mis-adjusted color bars image

Raffriff42: table headers; move 1 par to top

2015-04-13T00:03:59Z

table headers; move 1 par to top

Raffriff42: show normalized 75% color values; add blue-only image; add some citations

2015-04-12T22:02:03Z

show normalized 75% color values; add blue-only image; add some citations

Raffriff42: add image; formatting tweaks

2015-04-12T02:20:37Z

add image; formatting tweaks

Show changes

Admin: todo - add picture

2015-04-11T15:52:04Z

todo - add picture

← Older revision		Revision as of 20:35, 7 May 2020
Line 68:		Line 68:

	==== Y,Cb,Cr [16,235] ====		==== Y,Cb,Cr [16,235] ====
−
−	~~As an example, consider the color yellow (0.75,0.75,0) (the used color conversions can be found here: [[Color conversions]]):~~
−	~~yellow:~~
−	~~Y = KrR + KgG + KbB = 0.75(0.299 + 0.587)219 + 16 = 0.6645219 + 16 = 161.53 = 162~~
−	~~Cb = (B-Y)/(1-Kb) = (0 - 0.6645)/(1-0.114)112 + 128 = -0.75112 + 128 = 44~~
−	~~Cr = (R-Y)/(1-Kr) = (0.75 - 0.6645)/(1-0.299)112 + 128 = 0.1220112 + 128 = 141.66 = 142~~

	{\| border="1"		{\| border="1"

@@ Line 132: / Line 132: @@
 ! color
 ! RGB
-! (hex)
+! hex
 |-
-| light grey
+| gray
 | 180,180,180
 | b4b4b4
@@ Line 162: / Line 166: @@
 | 1010b4
 |-
-| white
+| 100% white
 | 235,235,235
 | ebebeb
@@ Line 170: / Line 174: @@
 | 101010
 |}
 == 100/0/100/0 bars using Rec.601 coefficients ==

@@ Line 82: / Line 82: @@
 |-
 | gray
-| 68,128,128
+| 104,128,128
 | b48080
 |-
@@ Line 121: / Line 121: @@
 | 108080
 |}
 ==== R,G,B [16,235] ====

@@ Line 79: / Line 79: @@
 ! color
 ! YCbCr
-! (hex)
+! hex
 |-
-| light grey
+| gray
-| 180,128,128
+| 68,128,128
 | b48080
 |-
 | yellow
-| 162,44,142
+| 168,44,136
-| a22c8e
+| a82c88
 |-
 | cyan
-| 131,156,44
+| 145,147,44
-| 839c2c
+| 91932c
 |-
 | green
-| 112,72,58
+| 133,63,52
-| 70483a
+| 853f34
 |-
 | magenta
-| 84,184,198
+| 63,193,204
-| 54b8c6
+| 3fc1cc
 |-
 | red
-| 65,100,212
+| 51,109,212
-| 4164d4
+| 336dd4
 |-
 | blue
-| 35,212,114
+| 28,212,120
-| 23d472
+| 1cd478
 |-
-| white
+| 100% white
 | 235,128,128
 | eb8080

@@ Line 264: / Line 264: @@
 ==== the pluge using Rec.601 coefficients ====
 -4/0/4 IRE levels: ...
@@ Line 361: / Line 363: @@
   +Q = rgb{75, 15, 126} = hex rgb{4B, 0F, 7E}
   -I = rgb{0, 58, 98} = hex rgb{0, 3A, 62}
 == 100/0/75/0 bars using Rec.709 coefficients ==

@@ Line 53: / Line 53: @@
-In the SMPTE color bars the top two-thirds of the image consists of seven colorbars and below them, seven shorter bars or boxes. When a television receiver or monitor is properly adjusted and set to filter out all colors except for blue, there is no visible distinction between the bars and the boxes beneath them, and you should see four solid blue bars.
+In the SMPTE color bars the top two-thirds of the image consists of seven colorbars and below them, seven shorter bars or boxes. When a television receiver or monitor is properly adjusted and set to filter out all colors except for blue, there is no visible distinction between the bars and the boxes beneath them, and you should see four solid blue bars like this:
 [[File:SMPTE_Color_Bars-320x240-blue_only.png]]
 The bottom section contains a pattern called the Pluge<sup>[http://en.wikipedia.org/wiki/Picture_line-up_generation_equipment]</sup>, which is used to set up monitor black levels<sup>[http://www.spearsandmunsil.com/portfolio/setting-the-brightness-control-2]</sup>

@@ Line 1: / Line 1: @@
-== SMPTE color bars ==
+Description of encoded colour-bar<sup>[http://en.wikipedia.org/wiki/SMPTE_color_bars]</sup> signals according to the 4:2:2 level of Recommendation ITU-R BT.601 and ITU-R BT.709. Those are described in Rec. ITU-R BT.801-1<sup>[http://www.itu.int/rec/R-REC-BT.801/en]</sup> and Rec. ITU-R BT.1927).
 filter: [[ColorBars|ColorBars and ColorBarsHD]]
-Description of encoded colour-bar<sup>[http://en.wikipedia.org/wiki/SMPTE_color_bars]</sup> signals according to the 4:2:2 level of Recommendation ITU-R BT.601 and ITU-R BT.709. Those are described in Rec. ITU-R BT.801-1<sup>[http://www.itu.int/rec/R-REC-BT.801/en]</sup> and Rec. ITU-R BT.1927).
+== SMPTE color bars ==
 [[File:SMPTE_Color_Bars-320x240.png]]
@@ Line 12: / Line 12: @@
 {| border="1"
 |-
 | 75% white
@@ Line 35: / Line 38: @@
 |}
-Black and 100% white in this colorspace are given by
+Black and white in this colorspace are given by
 {| border="1"
 |-
-| white
+! color
 | (1, 1, 1)
 |-

@@ Line 1: / Line 1: @@
 == SMPTE color bars ==
-filter: [[ColorBars|ColorBars,ColorBarsHD]] ...
+filter: [[ColorBars|ColorBars and ColorBarsHD]]
-Description of encoded colour-bar signals according to the 4:2:2 level of Recommendation ITU-R BT.601 and ITU-R BT.709. Those are described in Rec. ITU-R BT.801-1) and Rec. ITU-R BT.1927).
+Description of encoded colour-bar<sup>[http://en.wikipedia.org/wiki/SMPTE_color_bars]</sup> signals according to the 4:2:2 level of Recommendation ITU-R BT.601 and ITU-R BT.709. Those are described in Rec. ITU-R BT.801-1<sup>[http://www.itu.int/rec/R-REC-BT.801/en]</sup> and Rec. ITU-R BT.1927).
 [[File:SMPTE_Color_Bars-320x240.png]]
@@ Line 9: / Line 9: @@
 The SMPTE color bars - RGB [16,235] (Rec.601 coefficients, 75% intensity)
+From left to right, 75% colorbars consists of the following colors (given in normalized colorspace rgb [0,1]):
 {| border="1"
 |-
-| light grey
+| 75% white
-| (0.75,0.75,0.75)
+| (0.75, 0.75, 0.75)
 |-
-| yellow
+| 75% yellow
-| (1,1,0)
+| (0.75, 0.75, 0)
 |-
-| cyan
+| 75% cyan
-| (0,1,1)
+| (0, 0.75, 0.75)
 |-
-| green
+| 75% green
-| (0,1,0)
+| (0, 0.75, 0)
 |-
-| magenta
+| 75% magenta
-| (1,0,1)
+| (0.75, 0, 0.75)
 |-
-| red
+| 75% red
-| (1,0,0)
+| (0.75, 0, 0)
 |-
-| blue
+| 75% blue
-| (0,0,1)
+| (0, 0, 0.75)
 |}
-black and white are given by
+Black and 100% white in this colorspace are given by
 {| border="1"
 |-
 | white
-| (1,1,1)
+| (1, 1, 1)
 |-
 | black
-| (0,0,0)
+| (0, 0, 0)
 |}
@@ Line 469: / Line 473: @@
 References:
 * [http://www.itu.int/rec/R-REC-BT/recommendation.asp?lang=en&parent=R-REC-BT.801 Rec. ITU-R BT.801-1] (Rec.601 coefficients)
 * [http://www.itu.int/rec/R-REC-BT/recommendation.asp?lang=en&parent=R-REC-BT.1729 Rec. ITU-R BT.1729] (Rec.709 coefficients)

@@ Line 3: / Line 3: @@
 filter: [[ColorBars]] ...
-Description of encoded colour-bar signals according to the 4:2:2 level of Recommendation ITU-R BT.601 and ITU-R BT.709. Those are described in Rec. ITU-R BT.801-1) and Rec. ITU-R BT.18..).
+Description of encoded colour-bar signals according to the 4:2:2 level of Recommendation ITU-R BT.601 and ITU-R BT.709. Those are described in Rec. ITU-R BT.801-1) and Rec. ITU-R BT.1927).
 {| border="1"
@@ Line 406: / Line 406: @@
 References:
-* Rec. ITU-R BT.801-1 (Rec.601 coefficients)
+* [http://www.itu.int/rec/R-REC-BT/recommendation.asp?lang=en&parent=R-REC-BT.801 Rec. ITU-R BT.801-1] (Rec.601 coefficients)
-* Rec. ITU-R BT.18.. (Rec.709 coefficients)
+* [http://www.itu.int/rec/R-REC-BT/recommendation.asp?lang=en&parent=R-REC-BT.1729 Rec. ITU-R BT.1729] (Rec.709 coefficients)
 * http://en.wikipedia.org/wiki/Color_bars
+* todo: see links in http://forum.doom9.org/showthread.php?p=795723#post795723
 [[Category:Advanced topics]]