SMPTE ST 2073-4 PDF

This standard extends the Y'C'1C'2(A) image format defined in SMPTE ST 2073-3 to include subsampled color difference components (including 4:2:2, 4:2:0, 4:1:1, and 4:1:0). An alpha channel is optional and can have the same resolution as the Y′ channel or the same resolution as the C'1 and C'2 channels.

This standard adds the AlphaSampling parameter to specify whether the alpha component is subsampled.

Operations that resample color difference components are out of scope.