a) The depth or saturation of color. The saturation control adjusts the amplitude of color 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 color part. Chroma is the color 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 color difference signals related to the primary colors in the manner defined in the bit stream. The symbols used for the color difference signals are Cr and Cb.