What are video colour sampling ratios?
A. In video, bandwidth is a big issue affecting the cost of the system. In general, the lower the bandwidth requirements, the lower the cost. In order to reduce bandwidth, some systems use non-uniform colour sampling, which is almost analogous to digital image “lossy” compression. Say for instance you have a region of 4 pixels. Each of those pixels would be sampled for Luma (Y-component), but only two of them for chroma (I and Q components). In this case, the sampling ratio would be 4:2:2. 10.
