Apple Final Cut Pro 7 - Manual (Page 1798)

About Color Space Conversion in Compressor
When you use the Send to Compressor command, super-white values in Y
′
C
B
C
R
footage
are preserved. Also, standard definition and high definition footage are processed in their
appropriate color spaces (ITU-R BT.601 and ITU-R BT.709, respectively).
1798 Chapter 108 Using Compressor with Final Cut Pro