YCbCr

YCbCr is a family of digital color encoding schemes used in video and image processing. It encodes color by separating an image into one luminance component, Y, and two chrominance components, Cb and Cr. Y represents perceived brightness, while Cb and Cr encode color information as blue-difference and red-difference signals, respectively. Because human vision is more sensitive to luminance detail than to color detail, chrominance can be downsampled without perceptible loss, enabling data compression.

Digital YCbCr commonly refers to Y'CbCr, where Y' is gamma-corrected luma. The Y, Cb, Cr components are related to RGB through standard color matrices used in ITU-R BT.601 (standard-definition) and BT.709 (high-definition). In 8-bit digital representations, Cb and Cr are typically centered around 128, with Y occupying a broader 0–255 range in full-range data or 16–235 in video-range data.

Chroma subsampling is a key feature, with common configurations including 4:4:4 (no subsampling), 4:2:2 (half horizontal chroma resolution), and 4:2:0 (half both horizontally and vertically). These schemes reduce the amount of data for color information while preserving luminance detail. YCbCr supports various bit depths (8, 10, 12, 16 bits per channel) used across consumer and professional pipelines.

Applications are widespread, including digital video formats (MPEG, H.264/AVC, HEVC), broadcasting, and many image codecs such as JPEG, which transform RGB to YCbCr for compression. Terminology notes: Y'CbCr is often contrasted with YUV (linear-light) in some contexts, but the concept remains a color-encoding family, evolving with standards such as BT.2020 for wide-gamut and higher bit depth.