I am capturing an old TV show using ATI MMC 7.5

1. I am capturing using DVD-NTSC settings on ATI AIW Radeon
2. I am converting the capture using TMPEG's DVD-NTSC Template
3. I am multiplexing the resulting file....tmpeg often freezes during this process.
4. I am left with a slightly choppy picture quality,and the sound is garbled and out of sync ...not by much, only about a half second. My original DVD compliant capture is synced well with the sound, but it is only at 44.1 instead of 48k. My capture is not choppy at all.

Do I need to demultiplex my capture before I convert it with tmpeg??