The human eye is not as receptive to chrominance (color) detail as luminance (brightness) detail. Using color-space conversion, it is possible to convert RGB into the YUV color space, where Y is Luminance information, and U and V are derived color difference signals. At normal viewing distances, there is no perceptible loss incurred by sampling the color difference signals (U and V) at a lower rate to provide a simple and effective video compression to reduce storage and transmission costs
The Chroma Resampler function converts between chroma sub-sampling formats of 4:4:4, 4:2:2, and 4:2:0. There are a total of six conversions available for the three supported sub-sampling formats. Conversion is achieved using a FIR filter approach. Some conversions require filtering in only the horizontal dimension, only the vertical dimension, or both. Interpolation operations are implemented using a two-phase polyphase FIR filter. Decimation operations are implemented using a low-pass two-phase polyphase FIR filter to suppress chroma aliasing.