Check the data sheet. To use an advanced chip such as this you need to read and re-read it as many times as it takes to understand all of its functions and how they interact before you try and build something with it.
http://www.analog.com/media/en/technical-documentation/data-sheets/ADV7390_7391_7392_7393.pdf
page 74 for CGMS COPY GENERATION MANAGEMENT SYSTEM
page 50 for CEA861 it has to do with display identification as can be seen on Wikipedia
IRE is a unit in video processing