OK, the script dump you attached does not output AVI infoframe from the 7511. Not a problem except the sink will always expect DVI - RGB mode.
So with YCbCr input and INP_COLOR_SPACE = YCbCr 709 the output is RGB, colors look good
With RGB input and INP_COLOR_SPACE = RGB the output is RGB, color look good
The pixel bus was always RGB 24-bit