Most people on this thread haven't even submitted runs. That's super odd

Your best bet for recording off of a TV would be with a capture card, these are used so that people can record or stream gameplay footage from a television with a console. Currently, I use the Elgato HD60s Capture Card for all of my runs that aren't done on PC games, and I would highly recommend it as well. You can find cheaper alternatives for AV cables if needed, and that's probably what you'll want to use if you plan on running off of dreamcast