Screen Dimensions

Yo. I’m creating a dvd to be shown on a plasma screen. I’m doing some animation in flash but I’m not sure what dimensions to use so that it fits the tv. I assume I just need to get the ratio right (one that is supported by the plasma) and then the size will be determined when I burn the disc? If that’s right, what ratio do I need, as in what is it likely to support? Or am I completely wrong? Thanks in advance.