Color space is typically tied to a codec. ProRes 422 can only be 4:2:2...thus why it is called ProRes "422." HDV is a format that can go 4:2:0...as are a few formats of H.264...and XDCAM. So...when they say they need it to be 4:2:0...what CODEC do they also want it to be? Only certain codecs can be 4:2;0. I'd think the codec type was more important than the color space.