DVXUser has a concise, easy to understand explanation of colour sampling methods in digital video, with diagrams!
YouÃ¢â‚¬â„¢ve seen the numbers: 4:2:0, 4:4:4, 3:1:1, 3:1.5:1.5, 4:1:1, 4:2:2Ã¢â‚¬Â¦ What does it all mean? And how does it affect your video? WhatÃ¢â‚¬â„¢s better, whatÃ¢â‚¬â„¢s worse, and when does it matter?
What those numbers are referring to is a technique in digital video commonly called Ã¢â‚¬Å“color sampling.Ã¢â‚¬Â The concept can be a bit confusing to those not used to working with video in the digital domain. In video, itÃ¢â‚¬â„¢s common practice to not actually record all the color in an image, but rather to average the pixels together to cut down on the bandwidth. Color sampling is, in effect, a form of compression. The more compressed the engineers can make the color channel, the less bandwidth the signal occupies and the easier it is to record, transmit, or broadcast.