YCbCr - Revision history

Artoria2e5 at 04:05, 17 July 2023

2023-07-17T04:05:43Z

← Older revision		Revision as of 21:05, 16 July 2023
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	Many modern video codecs rely on a YCbCr colorspace. The correct written expression for this colorspace is YC<sub>b</sub>C<sub>r</sub>, with the 'b' and 'r' characters as subscripts. This is what the components represent:		Many modern video codecs rely on a YCbCr colorspace. The correct written expression for this colorspace is YC<sub>b</sub>C<sub>r</sub>, with the 'b' and 'r' characters as subscripts. This is what the components represent:

	* Y = luma, an approximate version of luminance / intensity (See [[Wikipedia~~:luma]~~] for ~~difference~~ from true luminance)		* Y = luma, an approximate version of luminance / intensity (See [https://en.wikipedia.org/wiki/Luma_(video) Wikipedia] for how it differs from true luminance)
	* C<sub>b</sub> = "blue chrominance", or more precisely the color deviation from gray on a blue-yellow axis		* C<sub>b</sub> = "blue chrominance", or more precisely the color deviation from gray on a blue-yellow axis
	* C<sub>r</sub> = "red chrominance", or more precisely the color deviation from gray on a red-cyan axis		* C<sub>r</sub> = "red chrominance", or more precisely the color deviation from gray on a red-cyan axis

Artoria2e5: eh, not that much

2023-07-17T03:47:30Z

eh, not that much

← Older revision		Revision as of 20:47, 16 July 2023
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	Green can be calculated based on these three values.		Green can be calculated based on these three values.

	'''YUV''': YC<sub>b</sub>C<sub>r</sub> is often falsely mixed up with YUV. Properly speaking, YUV is the analogue PAL color encoding, where the color components U and V differ ~~quite a lot~~ from C<sub>b</sub> and C<sub>r</sub>, found in PAL TV transmission and analogue video tapes. Nevertheless, it's very common for software to call YC<sub>b</sub>C<sub>r</sub> "YUV".		'''YUV''': YC<sub>b</sub>C<sub>r</sub> is often falsely mixed up with YUV. Properly speaking, YUV is the analogue PAL color encoding, where the color components U and V differ from C<sub>b</sub> and C<sub>r</sub>, found in PAL TV transmission and analogue video tapes. Nevertheless, it's very common for software to call YC<sub>b</sub>C<sub>r</sub> "YUV".

	'''Chroma subsampling:''' Note that with most digital [[RGB]] color encodings, every single pixel has a different R, G and B sample. The same is not true with many YC<sub>b</sub>C<sub>r</sub> (including [[YCoCg\|YC<sub>o</sub>C<sub>g</sub>]]) color encodings. These YC<sub>b</sub>C<sub>r</sub> variants operate on the empirical evidence that the human eye is more sensitive to variations in the intensity of a pixel rather than variations in color. Thus, every pixel in an image of such a YC<sub>b</sub>C<sub>r</sub> variant has an associated Y sample, but groups of pixels share C<sub>b</sub> and C<sub>r</sub> samples.		'''Chroma subsampling:''' Note that with most digital [[RGB]] color encodings, every single pixel has a different R, G and B sample. The same is not true with many YC<sub>b</sub>C<sub>r</sub> (including [[YCoCg\|YC<sub>o</sub>C<sub>g</sub>]]) color encodings. These YC<sub>b</sub>C<sub>r</sub> variants operate on the empirical evidence that the human eye is more sensitive to variations in the intensity of a pixel rather than variations in color. Thus, every pixel in an image of such a YC<sub>b</sub>C<sub>r</sub> variant has an associated Y sample, but groups of pixels share C<sub>b</sub> and C<sub>r</sub> samples.

Artoria2e5: This will do.

2023-07-17T03:24:23Z

This will do.

← Older revision		Revision as of 20:24, 16 July 2023
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	Many modern video codecs rely on a YCbCr colorspace. The correct written expression for this colorspace is YC<sub>b</sub>C<sub>r</sub>, with the 'b' and 'r' characters as subscripts. This is what the components represent:		Many modern video codecs rely on a YCbCr colorspace. The correct written expression for this colorspace is YC<sub>b</sub>C<sub>r</sub>, with the 'b' and 'r' characters as subscripts. This is what the components represent:

	* Y = luma, an approximate version of luminance / intensity		* Y = luma, an approximate version of luminance / intensity (See [[Wikipedia:luma]] for difference from true luminance)
	* C<sub>b</sub> = "blue chrominance", or more precisely the color deviation from gray on a blue-yellow axis		* C<sub>b</sub> = "blue chrominance", or more precisely the color deviation from gray on a blue-yellow axis
	* C<sub>r</sub> = "red chrominance", or more precisely the color deviation from gray on a red-cyan axis		* C<sub>r</sub> = "red chrominance", or more precisely the color deviation from gray on a red-cyan axis
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	Green can be calculated based on these three values.		Green can be calculated based on these three values.

	YC<sub>b</sub>C<sub>r</sub> is often falsely mixed up with YUV, ~~which~~ is a ~~different colorspace that is not used~~ in ~~digital media but in analog~~ PAL~~-based stuff as analog~~ TV transmission ~~or analog~~ video tapes.		'''YUV''': YC<sub>b</sub>C<sub>r</sub> is often falsely mixed up with YUV. Properly speaking, YUV is the analogue PAL color encoding, where the color components U and V differ quite a lot from C<sub>b</sub> and C<sub>r</sub>, found in PAL TV transmission and analogue video tapes. Nevertheless, it's very common for software to call YC<sub>b</sub>C<sub>r</sub> "YUV".

	Note that with most digital [[RGB]] color encodings, every single pixel has a different R, G and B sample. The same is not true with many YC<sub>b</sub>C<sub>r</sub> ~~and also not necessarily true for~~ [[YCoCg\|YC<sub>o</sub>C<sub>g</sub>]] color encodings. These YC<sub>b</sub>C<sub>r</sub> variants operate on the empirical evidence that the human eye is more sensitive to variations in the intensity of a pixel rather than variations in color. Thus, every pixel in an image of such a YC<sub>b</sub>C<sub>r</sub> variant has an associated Y sample, but groups of pixels share C<sub>b</sub> and C<sub>r</sub> samples.		'''Chroma subsampling:''' Note that with most digital [[RGB]] color encodings, every single pixel has a different R, G and B sample. The same is not true with many YC<sub>b</sub>C<sub>r</sub> (including [[YCoCg\|YC<sub>o</sub>C<sub>g</sub>]]) color encodings. These YC<sub>b</sub>C<sub>r</sub> variants operate on the empirical evidence that the human eye is more sensitive to variations in the intensity of a pixel rather than variations in color. Thus, every pixel in an image of such a YC<sub>b</sub>C<sub>r</sub> variant has an associated Y sample, but groups of pixels share C<sub>b</sub> and C<sub>r</sub> samples.

	There are different matrix coefficients defined to convert encodings in the RGB color space to YCbCr. Among the more important ones are:		There are different matrix coefficients defined to convert encodings in the RGB color space to YCbCr. Among the more important ones are:

Artoria2e5 at 03:14, 17 July 2023

2023-07-17T03:14:59Z

← Older revision		Revision as of 20:14, 16 July 2023
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	* ITU BT.709 Used for High definition television (HDTV)		* ITU BT.709 Used for High definition television (HDTV)
	* ITU BT.2020 Used for Ultra high definition television		* ITU BT.2020 Used for Ultra high definition television
			* [[YCoCg]]

	Others are proprietary or less widely used, such as those defined in [[Cinepak]] and SMPTE 240M.		Others are proprietary or less widely used, such as those defined in [[Cinepak]] and SMPTE 240M.

Artoria2e5: not luminance, luma

2023-07-17T03:14:44Z

not luminance, luma

← Older revision		Revision as of 20:14, 16 July 2023
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	Many modern video codecs rely on a YCbCr colorspace. The correct written expression for this colorspace is YC<sub>b</sub>C<sub>r</sub>, with the 'b' and 'r' characters as subscripts. This is what the components represent:		Many modern video codecs rely on a YCbCr colorspace. The correct written expression for this colorspace is YC<sub>b</sub>C<sub>r</sub>, with the 'b' and 'r' characters as subscripts. This is what the components represent:

	* Y = luminance~~, or~~ intensity		* Y = luma, an approximate version of luminance / intensity
	* C<sub>b</sub> = "blue chrominance", or more precisely the color deviation from gray on a blue-yellow axis		* C<sub>b</sub> = "blue chrominance", or more precisely the color deviation from gray on a blue-yellow axis
	* C<sub>r</sub> = "red chrominance", or more precisely the color deviation from gray on a red-cyan axis		* C<sub>r</sub> = "red chrominance", or more precisely the color deviation from gray on a red-cyan axis

Cecodere at 18:08, 17 December 2021

2021-12-17T18:08:06Z

← Older revision		Revision as of 11:08, 17 December 2021
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	There are different matrix coefficients defined to convert encodings in the RGB color space to YCbCr. Among the more important ones are:		There are different matrix coefficients defined to convert encodings in the RGB color space to YCbCr. Among the more important ones are:

	* ITU BT.601 ~~Mainly used~~ for Standard Definition television signals		* ITU BT.601 Used for Standard Definition television signals
	* ITU T.871 JPEG File Interchange Format (JFIF)		* ITU T.871 JPEG File Interchange Format (JFIF)
	* ITU BT.709 ~~Mainly used~~ for High definition television (HDTV)		* ITU BT.709 Used for High definition television (HDTV)
	* ITU BT.2020 ~~Mainly used~~ for Ultra high definition television		* ITU BT.2020 Used for Ultra high definition television

	Others are proprietary or less widely used, such as those defined in [[Cinepak]] and SMPTE 240M.		Others are proprietary or less widely used, such as those defined in [[Cinepak]] and SMPTE 240M.

Cecodere at 18:07, 17 December 2021

2021-12-17T18:07:30Z

← Older revision		Revision as of 11:07, 17 December 2021
Line 11:		Line 11:
	Note that with most digital [[RGB]] color encodings, every single pixel has a different R, G and B sample. The same is not true with many YC<sub>b</sub>C<sub>r</sub> and also not necessarily true for [[YCoCg\|YC<sub>o</sub>C<sub>g</sub>]] color encodings. These YC<sub>b</sub>C<sub>r</sub> variants operate on the empirical evidence that the human eye is more sensitive to variations in the intensity of a pixel rather than variations in color. Thus, every pixel in an image of such a YC<sub>b</sub>C<sub>r</sub> variant has an associated Y sample, but groups of pixels share C<sub>b</sub> and C<sub>r</sub> samples.		Note that with most digital [[RGB]] color encodings, every single pixel has a different R, G and B sample. The same is not true with many YC<sub>b</sub>C<sub>r</sub> and also not necessarily true for [[YCoCg\|YC<sub>o</sub>C<sub>g</sub>]] color encodings. These YC<sub>b</sub>C<sub>r</sub> variants operate on the empirical evidence that the human eye is more sensitive to variations in the intensity of a pixel rather than variations in color. Thus, every pixel in an image of such a YC<sub>b</sub>C<sub>r</sub> variant has an associated Y sample, but groups of pixels share C<sub>b</sub> and C<sub>r</sub> samples.

	There are different matrix coefficients defined to convert RGB color space to YCbCr. Among the more important ones are:		There are different matrix coefficients defined to convert encodings in the RGB color space to YCbCr. Among the more important ones are:

	* ITU BT.601 Mainly used for Standard Definition television signals		* ITU BT.601 Mainly used for Standard Definition television signals

Cecodere at 18:06, 17 December 2021

2021-12-17T18:06:03Z

← Older revision		Revision as of 11:06, 17 December 2021
Line 14:		Line 14:

	* ITU BT.601 Mainly used for Standard Definition television signals		* ITU BT.601 Mainly used for Standard Definition television signals
	* ITU T-871 JPEG File Interchange Format (JFIF)		* ITU T.871 JPEG File Interchange Format (JFIF)
	* ITU BT.709 Mainly used for High definition television (HDTV)		* ITU BT.709 Mainly used for High definition television (HDTV)
	* ITU BT.2020 Mainly used for Ultra high definition television		* ITU BT.2020 Mainly used for Ultra high definition television

Cecodere: Provide more information on origins of YCbCr formats

2021-12-17T18:05:25Z

Provide more information on origins of YCbCr formats

← Older revision		Revision as of 11:05, 17 December 2021
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	Note that with most digital [[RGB]] color encodings, every single pixel has a different R, G and B sample. The same is not true with many YC<sub>b</sub>C<sub>r</sub> and also not necessarily true for [[YCoCg\|YC<sub>o</sub>C<sub>g</sub>]] color encodings. These YC<sub>b</sub>C<sub>r</sub> variants operate on the empirical evidence that the human eye is more sensitive to variations in the intensity of a pixel rather than variations in color. Thus, every pixel in an image of such a YC<sub>b</sub>C<sub>r</sub> variant has an associated Y sample, but groups of pixels share C<sub>b</sub> and C<sub>r</sub> samples.		Note that with most digital [[RGB]] color encodings, every single pixel has a different R, G and B sample. The same is not true with many YC<sub>b</sub>C<sub>r</sub> and also not necessarily true for [[YCoCg\|YC<sub>o</sub>C<sub>g</sub>]] color encodings. These YC<sub>b</sub>C<sub>r</sub> variants operate on the empirical evidence that the human eye is more sensitive to variations in the intensity of a pixel rather than variations in color. Thus, every pixel in an image of such a YC<sub>b</sub>C<sub>r</sub> variant has an associated Y sample, but groups of pixels share C<sub>b</sub> and C<sub>r</sub> samples.

			There are different matrix coefficients defined to convert RGB color space to YCbCr. Among the more important ones are:

			* ITU BT.601 Mainly used for Standard Definition television signals
			* ITU T-871 JPEG File Interchange Format (JFIF)
			* ITU BT.709 Mainly used for High definition television (HDTV)
			* ITU BT.2020 Mainly used for Ultra high definition television

			Others are proprietary or less widely used, such as those defined in [[Cinepak]] and SMPTE 240M.

	For information on specific YC<sub>b</sub>C<sub>r</sub> formats, see the [[:Category:YCbCr Formats\|YCbCr formats category page]].		For information on specific YC<sub>b</sub>C<sub>r</sub> formats, see the [[:Category:YCbCr Formats\|YCbCr formats category page]].

	[[Category:Compression Theory]]		[[Category:Compression Theory]]

Elte: (general English edits ;-))

2009-03-17T08:22:59Z

(general English edits ;-))

← Older revision		Revision as of 01:22, 17 March 2009
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	Many modern video codecs rely on a YCbCr colorspace. ~~More correctly~~ written this is YC<sub>b</sub>C<sub>r</sub>, with the 'b' and 'r' characters as subscripts. This is what the components represent:		Many modern video codecs rely on a YCbCr colorspace. The correct written expression for this colorspace is YC<sub>b</sub>C<sub>r</sub>, with the 'b' and 'r' characters as subscripts. This is what the components represent:

	* Y = luminance, or intensity		* Y = luminance, or intensity