Problems writing MPEG-2 files as video DVD.

[George]

Hi,
    I have been trying to write some MPEG-2 files as DVD video's using Toast Titanium 7 without any luck. What happens is that the DVD video appears to work fine. However, when I attempt to jump to another chapter, the audio portion jumps to that chapter fine, but the video remains frozen at the point where I first tried to change chapters. What's interesting is that this problem affects most, but not all of my mpeg-2 video files. I have also tried program called "Sizzle", but got the same results. Someone suggested to me that it might be related to "long GOP" in the MPEG-2 file. (I don't fully understand what this is, though)  I was able to convert the videos to other formats using a program called "ffmpegX" but there was a huge drop in video quality, which I do not want. I also tried iDVD, but that does not support  MPEG-2 files.
    Does anyone have any ideas on what I could do? Any help is greatly appreciated.


Thanks!
George