Thank you very much for your quick reply, olyteddy. Even though the answer wasn't as simple as I had hoped, at least I understand what you're saying!
So, the question really is not if my tv will "play MP4s" but what kind of MP4 I am trying to play. Is that right?
If I look at one of the MP4s I was really hoping would work on my tv, the properties tab tells me that the file is an MPEG-4 (.mp4) ; the file info tab in Quicktime tells me that the file format uses the codec H.264, 740 x 320, AAC, Stereo (I D) 48,000 kHz. This, if I understand correctly, is a standard codec that shouldn't pose any problems.
And, according to the specs I linked to in the last post, MPEG4 are listed as playable. But this one isn't! :sad:
How do I know what sort of file I have? Are the tv specs enough to know if it is compatible, or do I need more info?
Thanks again for so much help!