YCbCr / YUV

Luma/chroma color space — basis of nearly every video and JPEG codec.

Y carries luminance, Cb and Cr the color differences. Because the eye is more sensitive to brightness than color, chroma subsampling (4:2:0 etc.) can heavily compress chroma channels without visible loss. JPEG, MPEG, H.26x and AV1 all use YCbCr internally.