ColorBars theory - Revision history

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

2020-05-07T20:35:52Z

Y,Cb,Cr [16,235]

← Older revision		Revision as of 22:35, 7 May 2020
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	==== 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"

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

2020-05-07T20:22:34Z

R,G,B [16,235]

← Older revision		Revision as of 22:22, 7 May 2020
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	! color		! color
	! RGB		! RGB
	! (hex)		! hex
	\|-		\|-
	\| ~~light grey~~		\| gray
			\| 104,104,104
			\| b4b4b4
			\|-
			\| 75% white
	\| 180,180,180		\| 180,180,180
	\| b4b4b4		\| b4b4b4
Line 162:		Line 166:
	\| 1010b4		\| 1010b4
	\|-		\|-
	\| white		\| 100% white
	\| 235,235,235		\| 235,235,235
	\| ebebeb		\| ebebeb
Line 170:		Line 174:
	\| 101010		\| 101010
	\|}		\|}


	== 100/0/100/0 bars using Rec.601 coefficients ==		== 100/0/100/0 bars using Rec.601 coefficients ==

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

2020-05-07T19:38:12Z

Y,Cb,Cr [16,235]

← Older revision		Revision as of 21:38, 7 May 2020
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	\|-		\|-
	\| gray		\| gray
	\| 68,128,128		\| 104,128,128
	\| b48080		\| b48080
	\|-		\|-
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	\| 108080		\| 108080
	\|}		\|}


	==== R,G,B [16,235] ====		==== R,G,B [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.

← Older revision		Revision as of 21:10, 7 May 2020
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	! color		! color
	! YCbCr		! YCbCr
	! (hex)		! hex
	\|-		\|-
	\| ~~light grey~~		\| gray
	\| 180,128,128		\| 68,128,128
			\| b48080
			\|-
			\| 75% white
			\| 180,128,128
	\| b48080		\| b48080
	\|-		\|-
	\| yellow		\| yellow
	\| ~~162~~,44,~~142~~		\| 168,44,136
	\| ~~a22c8e~~		\| a82c88
	\|-		\|-
	\| cyan		\| cyan
	\| ~~131~~,~~156~~,44		\| 145,147,44
	\| ~~839c2c~~		\| 91932c
	\|-		\|-
	\| green		\| green
	\| ~~112~~,72,58		\| 133,63,52
	\| ~~70483a~~		\| 853f34
	\|-		\|-
	\| magenta		\| magenta
	\| 84,~~184~~,~~198~~		\| 63,193,204
	\| ~~54b8c6~~		\| 3fc1cc
	\|-		\|-
	\| red		\| red
	\| 65,~~100~~,212		\| 51,109,212
	\| ~~4164d4~~		\| 336dd4
	\|-		\|-
	\| blue		\| blue
	\| 35,212,~~114~~		\| 28,212,120
	\| ~~23d472~~		\| 1cd478
	\|-		\|-
	\| white		\| 100% white
	\| 235,128,128		\| 235,128,128
	\| eb8080		\| eb8080

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

2016-03-06T15:57:31Z

the pluge using Rec.601 coefficients

← Older revision		Revision as of 17:57, 6 March 2016
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	==== the pluge using Rec.601 coefficients ====		==== the pluge using Rec.601 coefficients ====

			todo: fix (see http://forum.videohelp.com/threads/377237-Purple-green-VHS?p=2435970&viewfull=1#post2435970, and check code of Colorbars again)

	-4/0/4 IRE levels: ...		-4/0/4 IRE levels: ...
Line 361:		Line 363:
	+Q = rgb{75, 15, 126} = hex rgb{4B, 0F, 7E}		+Q = rgb{75, 15, 126} = hex rgb{4B, 0F, 7E}
	-I = rgb{0, 58, 98} = hex rgb{0, 3A, 62}		-I = rgb{0, 58, 98} = hex rgb{0, 3A, 62}


	== 100/0/75/0 bars using Rec.709 coefficients ==		== 100/0/75/0 bars using Rec.709 coefficients ==

Raffriff42: add mis-adjusted color bars image

2015-04-13T00:07:02Z

add mis-adjusted color bars image

← Older revision		Revision as of 02:07, 13 April 2015
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]]		[[File:SMPTE_Color_Bars-320x240-blue_only.png]]

			If the colors are mis-adjusted, you may see a visible break in the bars like this:

			[[File:SMPTE_Color_Bars-320x240-blue_only-bad.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>		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>

Raffriff42: table headers; move 1 par to top

2015-04-13T00:03:59Z

table headers; move 1 par to top

← Older revision		Revision as of 02:03, 13 April 2015
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]]		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]]		[[File:SMPTE_Color_Bars-320x240.png]]
Line 12:		Line 12:

	{\| border="1"		{\| border="1"
			\|-
			! color
			! RGB
	\|-		\|-
	\| 75% white		\| 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"		{\| border="1"
	\|-		\|-
	\| white		! color
			! RGB
			\|-
			\| 100% white
	\| (1, 1, 1)		\| (1, 1, 1)
	\|-		\|-

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

← Older revision		Revision as of 00:02, 13 April 2015
Line 1:		Line 1:
	== SMPTE color bars ==		== 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]]		[[File:SMPTE_Color_Bars-320x240.png]]
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	The SMPTE color bars - RGB [16,235] (Rec.601 coefficients, 75% intensity)		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]):
	In the SMPTE color bars the top two-thirds of the image consists of seven colorbars. ... Rec.601 75%, later Rec.709 at 100%. Below those seven bars a combination of blue, magenta, cyan, and white boxes is given. When a television receiver is set to filter out all colors except for blue, these boxes, combined with the of color bars, are used to properly adjust the color controls. If they are properly adjusted, there is no visible distinction between the bars and the boxes, and you should see four solid blue bars. The bottom section of the test pattern is called the pluge ... is used to ...

	From left to right, ~~the~~ colorbars consists of the following colors (given in normalized colorspace rgb [0,1]):

	{\| border="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"		{\| border="1"
	\|-		\|-
	\| white		\| white
	\| (1,1,1)		\| (1, 1, 1)
	\|-		\|-
	\| black		\| black
	\| (0,0,0)		\| (0, 0, 0)
	\|}		\|}


			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.

			[[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>


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	References:		References:

			* [http://en.wikipedia.org/wiki/SMPTE_color_bars SMPTE Color Bars]
	* [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.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)		* [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)

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 17:52, 11 April 2015
Line 3:		Line 3:
	filter: [[ColorBars]] ...		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"		{\| border="1"
Line 406:		Line 406:
	References:		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		* http://en.wikipedia.org/wiki/Color_bars
			* todo: see links in http://forum.doom9.org/showthread.php?p=795723#post795723

	[[Category:Advanced topics]]		[[Category:Advanced topics]]