YCbCr 4:2:0

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  • 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 reversed.

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.