SMPTE RP 175-1997

This practice describes a means of interconnecting digital video equipment operating in system M (525/60) and complying with the 4:4:4 sampling and encoding parameters defined in CCIR Recommendation 601-2, annex 1, with a nominal sampling frequency of 13.5 MHz. Provision is made to carry a fourth, auxiliary, channel as part of the signal multiplex, yielding 4:4:4:4 (or 4x4) overall.
The interface is primarily defined to convey signals having luminance, color-difference, and auxiliary components. Signals having green, red, blue, and auxiliary components may alternatively be conveyed, as described in clause 6.
This is a 10-bit interface; however, provision has been made to interconnect all signals with 8- or 10-bit precision.