Difference between revisions of "YUV"
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== YUV 4:2:2 == | == YUV 4:2:2 == | ||
=== I422 === | === I422 === | ||
| − | In I422, like in I420, you have luma | + | In I422, like in I420, you have one luma plane '''''Y''''' and 2 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. | However, in I422, chroma planes (blue and red projections) are subsampled just in the horizontal dimension by a factor of 2. | ||
| Line 38: | Line 38: | ||
For a 2x2 group of pixels, you have 4 Y samples and 2 U and 2 V sample. | For a 2x2 group of pixels, you have 4 Y samples and 2 U and 2 V sample. | ||
| − | |||
= Packed = | = Packed = | ||
Revision as of 09:39, 19 May 2011
YUV is a class of pixel formats used in Video application and in VLC media player.
YUV is also colorspace and the way to represent pixels colors is based on Luminance and Chrominance.
Contents
Planar
YUV 4:2:0 (I420/YV12)
I420
In I420, you have one luma "luminance" plane Y and 2 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 one luma plane Y and 2 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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