A) The depth or saturation of color. The saturation control adjusts the amplitude of colour of the switcher’s matte and background outputs.

b) The (M) NTSC or (B, D, G, H, I) PAL video signal contains two pieces that make up what you see on the screen: the black and white (luma) part, and the colour part. Chroma is the colour part. Chroma can be further broken down into two properties of color: hue and saturation.

Chroma can also be described as a matrix, block, or single pel representing one of the two colour difference signals related to the primary colours in the manner defined in the bit stream. The symbols used for the colour difference signals are Cr and Cb.