No sound on some DVDs?

[Aeria]

I play DVDs on my computer, and most of them work fine.
However the Jimmy Carr Live DVD, and the Father Ted DVDs give me no sound.
I have tried playing the dvds using media player classic and wmp 10 but no luck.
I have an audigy 2 zs soundcard. Any ideas how to fix this problem?

[icq3800846]

Are they genuine DVDs or are they "home made" DVDs? In some instances videos compressed using an AC3 codec for the sound will be silent if you don't have the correct codec installed for playback.

[Aeria]

They are genuine.

[eloquence]

AC3 encoding is one possibility. If you get a 6.1 DTS soundtrack then some players (software and hardware) could fail to decode these properly. I've also had a player that didn't like some 5.1 soundtracks (possibly because of the choice of encoding), and missed the central channel, which gave sound effects but no dialog.
One way to test whether it's the audio encoding is to go into the DVD menu, and select the 2-channel audio option which is usually there. If this plays back with normal sound, then its an issue with the 5.1/6.1 decoding.

[Aeria]

Thanks for your help guys, I tried using Power DVD and the sound works fine.