Difference between revisions of "YCbCr 4:2:0"

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(mention FourCCs and coding formats)
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* FourCCs: I420, YV12
 
* FourCCs: I420, YV12
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(These FourCC names only reflect that YCbCr is often falsely mixed up with analog PAL's YUV color space.)
  
YUV 4:2:0 indicates a planar [[YUV]] colorspace where a 2x2 block of pixels in an image is represented by 4 Y samples, 1 for each pixel, but all 4 pixels share a U sample and a V sample.
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YCbCr 4:2:0 indicates a planar [[YCbCr]] colorspace where a 2x2 block of pixels in an image is represented by 4 Y samples, 1 for each pixel, but all 4 pixels share a Cb sample and a Cr sample.
  
YUV 4:2:0 can be transported within a general purpose container format. When the data is designated with a FourCC of I420 all of the Y data appears first, followed by the U data, then then V data. YV12 is the same with the order of the U and V planes revered.
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YCbCr 4:2:0 can be transported within a general purpose container format. When the data is designated with a FourCC of I420 all of the Y data appears first, followed by the Cb data, then then Cr data. YV12 is the same with the order of the Cb and Cr planes revered.
  
 
For trivia, the 12 in YV12 most likely refers to the number of bits needed to represent a single pixel. Since 6 bytes, or 48 bits represent 4 pixels, an average of 12 bits are required to represent a single pixel in this scheme.
 
For trivia, the 12 in YV12 most likely refers to the number of bits needed to represent a single pixel. Since 6 bytes, or 48 bits represent 4 pixels, an average of 12 bits are required to represent a single pixel in this scheme.
  
[[Category:YUV Formats]]
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[[Category:YCbCr Formats]]

Revision as of 06:46, 17 September 2006

  • FourCCs: I420, YV12

(These FourCC names only reflect that YCbCr is often falsely mixed up with analog PAL's YUV color space.)

YCbCr 4:2:0 indicates a planar YCbCr colorspace where a 2x2 block of pixels in an image is represented by 4 Y samples, 1 for each pixel, but all 4 pixels share a Cb sample and a Cr sample.

YCbCr 4:2:0 can be transported within a general purpose container format. When the data is designated with a FourCC of I420 all of the Y data appears first, followed by the Cb data, then then Cr data. YV12 is the same with the order of the Cb and Cr planes revered.

For trivia, the 12 in YV12 most likely refers to the number of bits needed to represent a single pixel. Since 6 bytes, or 48 bits represent 4 pixels, an average of 12 bits are required to represent a single pixel in this scheme.