AC3 avi audio, noise.

[marcobdivax]

Hi.
I've recently noted a noisy audio on center/rear channels when playing avi (zoomplayer,bsplayer,powerdivx) with ac3 audio (and playing the single .ac3 from powerdvd) with very low level audio scenes: the noise is quite a "ripple" with variable frequency, and it disappears (it really disappears, it is not covered) when a dialogue/any other audio starts.
Playing the original dvd with powerdvd seems not to have such a problem (but it use cybelink filters, not ac3filters 0.63b like avi players).
I extract ac3 using smartripper or ac3tools or vstrip, no differencies.
Valex stated that this noise is a "flag" in the ac3 (header, I suppose), but if correct, how to change it?
Of course, I'm trying to understand if the problem is related to my audio card (cm8738 chipset), 'cause other friends with the same card have the same problem (unfortunately I've no other friends with different sound cards...).
Suggestions?

Thanks a lot

marco

[MaTTeR]

Try the Moonlight Odio Dekoda filters noted in the AC3 FAQ to verify it's a problem with your sound card and not the filters.

Are you sure your using the latest CMedia drivers?

[marcobdivax]

Thanks for the answer, I'll try the filters asap.
And, yes, the first thing I've done was to update the drivers...

ciao

marco