The cause of this problem is that your TV out cards only work at TV frequency when the drivers have initialised and told them what to output.
Because the drivers are not initialised at bootup, the card is expecting to be outputting to a VGA Monitor and not a TV. Only when the windows drivers kick in does it understand what you are connected to.
Hence the rolling bios screens. As far as I know, there is no cure for this one. Unless the card manufacturer actually thought about it in the first place.
Best Regards,
Julian (Fozzy The Bear)