Thanks for your post. It was very informative.
Now, when I encoded my first DVD, using Nero Recode, I got three different .mp4 files containing the same movie. The size was different, but very close. Since this DVD had audio tracks in three languages (English, French, Russian), and subtitles in six languages, I suspect that it could play in more than one TV system. So, could it be that the three .mp4 files that Nero Recode created are actually in different TV systems? For example, one is in NTSC, another one is in PAL, and the third one is in SECAM. Is it possible to find out in which TV system an MPEG-4 file is encoded?