Then it means your VOB only has one track
I just tested loading a VOB in MPEG Mediator, and I can choose 3 AC3 tracks on this particular movie. How about using DVD Shrink
Just go into re-author mode, and visually select the range you want, then "Backup" that segment
You'll have a VOB with video, and AC3 audio of only the part you selected. Then you can extract that audio with DVD2AVI or MPEG Mediator

-kwag

Kwag,
you wrote:
" Then it means your VOB only has one track "

not only one, i have:
english LPCM 2 channels ,
english AC3 6 channels and
english DTS 5 channels
...for this reason i'm lost

well , i can try dvdshrink,never test it before but
now i'm more confused......
after the job in dvdshrink i back to the start point...

how can i extract only the wav files
from vobs using dvd2avi or mpegmediator


or i misunderstand it all!

Very simple
Load your VOBs in DVD2AVI (1.77.3 best )
Select the range you want to extract with the "[" and "]" keys. Then select your audio track, and select "demux" (For AC3 extraction) or "Decode" (For WAV decoding/extraction).
Hit save project, and enter a name. Now you'll have a small .d2v (which you can discard) and your short AC3 file or WAV file, which is the audio selected in your range.

-kwag

in the end......is very simple,
i "break my head" searching....
and the solution is in the start point.


but

thanks KW,another goal