Subject: [linux-audio-dev] Sound distortion with certain players/ac3 @ 48kHz
From: Peter Surda (shurdeek_AT_panorama.sth.ac.at)
Date: Fri Dec 07 2001 - 02:43:53 EET
Hi guys!
I hope this is not offtopic, but since it is about audio stuff under linux it
it should be ok.
So lemme describe the problem. Certain players, most notably vlc, produce
slightly distorted sound when playing 48kHz audio (like audiotracks on movie
DVDs). I don't know how to describe this distortion, I'd say it sounds
"tinny". My soundcard is SB-Live, but as far as I remember it also happens
with my onboard via82cxxx. I'd check but it is a little difficult to get
behind the box to replug the jacks.
When I play DVDs e.g. with xine, sound is ok, but when I play it with vlc, I
get this distortion. Right now I found other thing, I tested a "Das Boot" DVD.
It has 1 mpeg and 1 ac3 audiotrack. When I select the mpeg, vlc sounds ok, but
when I select ac3 it is distorted again. I asked in vlc-devel mailing list but
they probably don't feel it's important or are busy (you know how it goes).
I vaguely remember I heard similar sound distortions about a year ago, when I
tried to play divx with 48kHz audio using esd as output, but it was fixed
shortly thereafter.
I tried to force (compilation time defines) 48kHz frequency (instead of
default 44.1) and sdl output plugin instead of dsp one when compiling vlc, but
it didn't change anything.
So my question is, what could be causing this? Could it be that the ac3
decoder plugin is fscked? I have experience in programming multimedia stuff in
linux (I have patches in vlc (yes exactly the one I'm complaining about),
ogg123, mpg123, aviplay, gatos, XF86 and probably others I don't remember), so
I can probably fix it myself, but as I don't know where to look it could be
pretty difficult. So I thought I'd ask for hints here where the linux sound
gurus hang out :-)
Bye,
Peter Surda (Shurdeek) <shurdeek_AT_panorama.sth.ac.at>, ICQ 10236103, +436505122023
--
Reboot America.
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