In my experience the issue is almost always related to coming from or going to square progressive pixels into rectangular interlaced pixels.
Nothing to do with color space in my experience.
I've gotten jaggies going from sq. pixel Photoshop graphics into NTSC video that look fine in FCP in a computer but look jagged after render on an analog monitor.
I've also taken type generated in FCP that looks perfect in analog video but has jaggies when I knock it down to a progressive square pixel H.264 movie for viewing on the desktop.
Strange as it sounds, this business of placing the origin of the graphic on an odd-numbered vertical pixel actually seems to work. I first read that in an article that is someplace in Larry Jordan's website. (
http://www.larryjordan.biz )
That and enough gaussian blurring in the interlaced video environment to overcome any jaggies problems with curved shapes drawn in side interlaced video frames.
That's what I know.