- FourCCs: I420, YV12
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.
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.
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.