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Re: Audio Plays Fast in F11 w/ Dell Optiplex GX240

On Tue, 28 Jul 2009 07:28:15 -0700
Keith <ac7xc1nx comcast net> wrote:

> Here is the info from lspci
> 00:1f.5 Multimedia audio controller: Intel Corporation 82801BA/BAM
> AC'97 Audio Controller (rev 12)
> When ever I play an audio file like ogg or mp3 the audio is playing
> slightly too fast. Video seems to be OK, but it is hard to tell with
> the timing be off with the sound. I checked Fedora Forums and others
> have reported it, but found no solutions have been found. I have never
> experinced this problem with this sound card with winXP, Ubuntu or
> CentOS so I don't know why it has started now. Does anyone know of any
> settings I should check or change to isolate or fix this problem?
> Thanks for any help or tips. 
I assume you are using pulseaudio, on by default in Fedora.  I think the
default rate for the sound server is 44100 Hz, but your problem sounds
like it is actually running at 48000 Hz.  When you play the sound from
an ogg or mp3 it is probably encoded at a frame rate of 44100 Hz, the
CD standard. So it will play about 10% fast if it is not resampled to
48000 Hz. Movies are encoded at 48000 Hz, so they will play properly
without any resampling.

Pulse, by default, resamples on the fly to adjust the sound stream to
the server rate that it has set.  (In general, this will introduce
distortion or artifacts into the sound.  If you are listening to an mp3
or ogg, it is already distorted by being lossy, so no big deal. If
listening to high quality (lossless) sound, this will be noticeable.)
It sounds like pulse isn't resampling on your hardware. Check the
configuration to see if it is turned off. If you can't resolve this,
you should open a bug for this problem at http://bugzilla.redhat.com
against pulseaudio.

The fact it doesn't happen on other linux distributions implies that it
is a setting, and not a bug.  Though it could be a bug introduced after
your experience on those systems.  Windows experience doesn't apply in
this case, other than indicating the hardware is working correctly.

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