YCbCr 4:2:2

• FourCCs: YUY2, UYVY, YUV2 (Apple Component Video stored in MOV files)
• Samples: http://samples.mplayerhq.hu/V-codecs/YUV2/

(These FourCC names only reflect that the YCbCr of digital media is often falsely mixed up with analog PAL's YUV color space.)

YCbCr 4:2:2 is a packed YCbCr format in which a pair of consecutive pixels is represented by 1 Y sample each but share a Cb sample and a Cr sample.

This type of data may be packaged in a container format with a a FourCC of YUY2 which indicates the following byte formatting:

 Y0 Cb Y1 Cr

The first pixel is a a function of (Y0, Cb, Cr) and the second pixel is a function of (Y1, Cb, Cr). Alternately, the FourCC UYVY is used to indicate YCbCr 4:2:2 data with a byteswapped order:

 Cb Y0 Cr Y1

For trivia, the 2 in YUY2 most likely refers to the number of bytes needed to represent a single pixel. Since 4 bytes represent 2 pixels, an average of 2 bytes are required to represent a single pixel in this scheme.