Chroma subsampling

Chroma subsampling is a type of compression for videos, that uses less information for chroma information than for luma information. This takes advantage of the fact, that humans eyes have a higher resolution for luma information than for chroma information.

The subsampling scheme is expressed with three to four numbers. For example:
 * 4:4:4
 * 4:2:2
 * 4:1:1
 * 4:2:0