Subject: Re: [linux-audio-dev] weird distortion with alsa latency test
From: Andre Pang (ozone_AT_algorithm.com.au)
Date: Wed Nov 14 2001 - 01:43:27 EET
On Tue, Nov 13, 2001 at 06:09:50PM +0100, Maarten de Boer wrote:
> Hi, I wrote this before, but I did not get any response.
>
> When I compile my kernel for i386 on an AMD Athlon, the
> alsa latency test is giving me weird distortion (knispering
> sound, like a dusty vinyl record)
> $ arecord -r 44100 -f S16_LE | aplay
> does not seem to have this problem.
>
> It really does not make much sense to me, and I am recompiling
> (again....) my kernel to make sure. Does anybody have a clue of
> what might be going on?
This might be related to your latency problem. What sound card
are you using? That will have an impact on the latency results.
e.g. the ALSA driver for my ymf744 sends latency through the roof
(~30ms); if I use the OSS driver that comes with the kernel, it's
~5ms.
But anyway, hearing crackling is a bad sign. I don't know
anything about the ALSA version of the latency test, but are your
OSS results good? Try using the OSS version of latencytest along
with ALSA's snd-pcm-oss emulation module. If you get good results
with that, it'll be the ALSA library or the ALSA functions in the
latencytest programs which are screwing up, not your system.
-- #ozone/algorithm <ozone_AT_algorithm.com.au> - trust.in.love.to.save
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