Digital Components Video Y' Cb'Cr'

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Digital component video uses a modified form of the Y' U' V' color format (analogue format). This format is called Y' Cb'Cr'. The Cb' component is the blue color difference component, similar to the U' component in Y' U' V'. Likewise, Cr' is the red color difference, similar to V'.

4:4:4 / 4:2:2 / 4:1:1 / 4:2:0 Sampling

The terminology: "4" is always the first number as a base, corresponding to the luminance part, if the luminance is captured fully (100%).

In 4:2:2 digital component video, the Y' component is sampled at twice the rate as each of the chroma components Cb' and Cr'. If the basic sample rate is 74.25 MHz, the Y' component is sampled at a rate of 74.25 MHz and the Cb' and Cr' components are sampled at half the rate: 37.125 MHz. In the 4:2:2 sampling per sample we have 50% luma and 50% chroma information (the chrome word is again 50% Cb' and 50% Cr'). In the HDTV digital component video the luma and the chroma information is treated separately. For 10-bit digital video, there is a 10-bit luma channel and a 10-bit chroma channel. The chrome samples alternate between a Cb' word and a Cr' word each time.

In 4:4:4 digital component video, the Y' component and both chroma components are sampled at the same sample rate. Each sample of luminance corresponds to one Cb sample and one Cr sample (like full RGB bandwidth, RGB and YCbCr and be converted fore and back).

In 4:1:1 digital component video the color resolution is quartered. For two neighboring luminance sample only one chroma sample with 50% Cb and 50% Cr is used.

In 4:2:0 digital component video the resolution i quartered too, but the color resolution is halved in both the horizontal and vertical directions.

In special formats like 3:1:1, three quarters of the horizontal resolution is captured. 8:4:4 is a format that uses two 4:2:2 scanner that are bonded together for the full chroma recording and a double bandwidth of luminance (high end film scanners).



MPEG compression, as used in DVDs, digital TV Receivers and digital camcorders (MiniDV, DV), is coded in YCbCr. The signal is transmitted over a digital link such as FireWire or SDI. The international standard ITU-R BT.601 for digital video defines both YCbCr and RGB color spaces.