Hi, I am not an expert on this, but a plain old DVD player is only capable of 480i output. Also, some newer ones may read computer format code but original DVD has a two folder structure. One for sound and the other for video I think.
To get your mp4 into DVD compatible form, you need to open it in a video editor like Primere Elements and the render it to DVD. That will burn the disk in the correct file structure. Or you could buy a blu-ray player. That should play the mp4 as is. Other alternative is to see if your set can accept an SD card directly. That should recognize the mp4.
Paul