Demux Problem?

Hello,

For two month I'm using dvd::rip now and encountered no problems until 
lately. I tried to work a downloaded dvd-image that showed to be two parts.

When finished I joined both parts (using ogmcat which works fine despite 
what the manpage says) and was rather annoyed when I noticed that 
suddenly there was no sound any longer.

So first I played the two parts separately. Part 1 was fine but no sound 
in Part 2. Some reading told me to use tcprobe to get some info. But it 
did not reveal any clue.

[tcprobe] OGG Multimedia Container
[tcprobe] summary for /opt/movies/dvdrip/AI2/avi/001/AI2-001.ogm, (*) = 
not default, 0 = not detected
import frame size: -g 624x336 [720x576] (*)
       frame rate: -f 25.000 [25.000] frc=3
      audio track: -a 0 [0] -e 48000,0,2 [48000,16,2] -n 0xfffe [0x2000] (*)
                   bitrate=224 kbps

So sound should be there, I thought - but it wasn't.

Then I tried to play the vob-files and everything was fine there (using
xine and ffplay), no missing sound. Why then doesn't it work?

 Now I tried tcprobe on the vob's and go rather mysterious results.

[tcprobe] MPEG program stream (PS)
[tcprobe] summary for /opt/movies/dvdrip/AI2/vob/001/AI2-001.vob, (*) = 
not default, 0 = not detected
import frame size: -g 720x576 [720x576]
     aspect ratio: 4:3 (*)
       frame rate: -f 25.000 [25.000] frc=3
                   PTS=0.1830, frame_time=40 ms, bitrate=10000 kbps
      audio track: -a 0 [0] -e 48000,16,2 [48000,16,2] -n 0x2000 [0x2000]
                   PTS=375.3886, bitrate=384 kbps
                   -D -9380 --av_fine_ms -5 (frames & ms) [0] [0]
detected (18) presentation unit(s) (SCR reset)

The values on PTS, -D and av_fine_ms sound somewhat mad especially the 
negative ones and the aspect ratio is 16:9 on all other vob's. So I 
think I found the culprit. Any idea how to mend it?

TIA

Helmut