YUV pixel formats

YUV formats fall into two distinct groups, the packed formats where Y, U (Cb) and V (Cr) samples are packed together into macropixels which are stored in a single array, and the planar formats where each component is stored as a separate array, the final image being a fusing of the three separate planes.

In the diagrams below, the numerical suffix attached to each Y, U or V sample indicates the sampling position across the image line, so, for example, V0 indicates the leftmost V sample and Yn indicates the Y sample at the (n+1)th pixel from the left.

Subsampling intervals in the horizontal and vertical directions may merit some explanation. The horizontal subsampling interval describes how frequently across a line a sample of that component is taken while the vertical interval describes on which lines samples are taken. For example, UYVY format has a horizontal subsampling period of 2 for both the U and V components indicating that U and V samples are taken for every second pixel across a line. Their vertical subsampling period is 1 indicating that U and V samples are taken on each line of the image.

For YVU9, though, the vertical subsampling interval is 4. This indicates that U and V samples are only taken on every fourth line of the original image. Since the horizontal sampling period is also 4, a single U and a single V sample are taken for each square block of 16 image pixels.

Also, if you are interested in YCrCb to RGB conversion, you may find this page helpful.

Packed YUV Formats

Planar YUV Formats