Difference between revisions of "YUV"
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− | YUV is a colorspace and a way to represent pixels | + | YUV is a colorspace and a way to represent pixels colors, based on Luminance and Chrominance. |
= Planar = | = Planar = |
Revision as of 21:41, 18 May 2011
YUV is a colorspace and a way to represent pixels colors, based on Luminance and Chrominance.
Contents
Planar
YUV 4:2:0 (I420/YV12)
I420
In I420, you have luma "luminance" planes Y and chroma planes U, V.
In I420, chroma planes (blue and red projections) are subsampled in both the horizontal and vertical dimensions by a factor of 2.
For a 2x2 group of pixels, you have 4 Y samples and 1 U and 1 V sample.
YV12
YV12 is exactly like I420, but with U and V order reversed.
NV12/NV21
NV12
Related to I420, in NV12, you have one luma "luminance" planes Y and one plane with U and V data interleaved. NV12 is considered as semiplanar.
In NV12, chroma planes (blue and red) are subsampled in both the horizontal and vertical dimensions by a factor of 2.
For a 2x2 group of pixels, you have 4 Y samples and 1 U and 1 V sample.
NV21
NV21 is like NV12, but with U and V order reversed: it starts with V
YUV 4:2:2
I422
In I422, like in I420, you have luma "luminance" planes Y and chroma planes U, V.
However, in I422, chroma planes (blue and red projections) are subsampled just in the horizontal dimension by a factor of 2. There is the same amount of lines than in the luma.
For a 2x2 group of pixels, you have 4 Y samples and 2 U and 2 V sample.
Packed
In packed formats, you only have one plane, with all the luma and chroma interleaved.
UYVY
Know as UYVY, Y422, UYNV
In UYVY, the chroma samples are sub-sampled by a factor of 2.
In UYVY, the succession for 2 pixels, starts by U then one luma, then V again and then another luma.
YUY2
Know as YUY2, YUYV, V422, YUNV
In YUY2, the chroma samples are sub-sampled by a factor of 2.
In YUY2, the succession for 2 pixels, starts by one luma, thenU, then another luma and then V again.
YVYU
YVYU is just like YUY2, but with U and V order reversed.
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