If you are going to order DL DVD's make sure to get Verbatim brand.
M2TS is found in Blu-ray, which is a completely different format from DVD-video. Even if it is compressed to fit onto a smaller disc, it wouldn't play on a regular DVD player, and not all Blu-ray players recognize Blu-ray video on DVD discs.
Not all DVD players will accept mp4 files either.
Are you editing the videos? Or just taking them straight from the camera?
One thing you might try is converting to DVD-video. Take your finished video, no matter what the format, and import into a free program called AVStoDVD. This will give you DVD-video output that will fit onto single layer dvds. Make sure to make NTSC compliant DVD-video if you are in the US, and use the HC encoder that is included with the program in a two pass encode.
AVStoDVD can be found here: http://www.videohelp.com/software/AVSTODVD
Use the direct download link.
Of course, I may have misunderstood what your program is doing, and you are already making DVD-video. If so, you can disregard the last bit of advice about AVStoDVD.