These numbers determine the horizontal and vertical sampling relative to the first number. The first number in both cases indicates the sample size, while the following two numbers represent chroma numbers. 4:2:0 only samples colors from half of the pixels in the first row and completely ignores the second row of the sample. However, in Chroma 4:2:2, the two chroma components are sampled at half the horizontal sample rate of luma, resulting in a reduction of horizontal chroma resolution by half. This reduces the bandwidth of an uncompressed video signal by half, but provides an higher quality image. This also means that it requires a high-speed HDMI cable.