What Is the YUV Color Space?
The YUV color model separates image data into one luminance component (Y) and two chrominance components (U and V). Unlike RGB, which mixes brightness and color information across all three channels, YUV isolates perceived brightness in a single value. This distinction is the foundation of nearly all modern video compression.
Y, U, and V — The Three Components
Y (Luma) represents the brightness of a pixel, calculated as a weighted sum of the red, green, and blue channels. The human eye is most sensitive to green light, which is why green carries the largest weight in the formula: Y = 0.299R + 0.587G + 0.114B.
U (Cb) encodes the difference between blue and luminance. It answers the question: how much bluer or yellower is this pixel compared to its brightness alone?
V (Cr) encodes the difference between red and luminance — capturing how much redder or more cyan a pixel appears relative to its brightness.
Why YUV Matters
The human visual system is far more sensitive to changes in brightness than to changes in color. By separating luma from chroma, YUV allows video codecs like H.264, H.265/HEVC, and AV1 to compress the U and V channels more aggressively — often at half or quarter resolution (chroma subsampling, e.g. 4:2:0) — without perceptible quality loss. This is why a 4K video stream fits into a few megabits per second instead of hundreds.
BT.601 vs. BT.709
The conversion coefficients between RGB and YUV depend on the standard. BT.601 (used on this page) was defined for standard-definition television. BT.709 is the HD standard with slightly different weights. BT.2020 extends the model further for ultra-high-definition and wide color gamut content. The math changes, but the principle — separating brightness from color — remains the same.
YUV vs. YCbCr
Strictly speaking, YUV refers to the analog encoding used in PAL and NTSC television, while YCbCr is the digital equivalent with scaled and offset values (typically 16–235 for Y and 16–240 for Cb/Cr). In practice, the terms are often used interchangeably. The interactive tool above uses full-range (0–255) digital values following the BT.601 matrix.