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Date:      Sun, 24 Aug 1997 14:47:09 -0700
From:      Amancio Hasty <hasty@rah.star-gate.com>
To:        "Louis A. Mamakos" <louie@TransSys.COM>
Cc:        multimedia@FreeBSD.ORG
Subject:   Re: problems with guspnp sound driver 
Message-ID:  <199708242147.OAA01373@rah.star-gate.com>
In-Reply-To: Your message of "Sun, 24 Aug 1997 14:46:22 EDT." <199708241846.OAA13555@whizzo.TransSys.COM> 

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Don't worry Louis , I think that I know what you mean and I am going
to work on the problem . Was listening yesterday to the mbone
and the problem surfaced however by just increasing the buffer
it appears to alleviate the problem .

Tnks for the feedback!

	Regards,
	Amancio

>From The Desk Of "Louis A. Mamakos" :
> 
> I've been noticing some problems with the sound driver lately.  It's hard
> to say exactly when it started.  
> 
> For a while now, I've been playing some mpeg compresses audio files in
> "jukebox" mode on the FreeBSD systems that I have at work and at home.
> I've got a  bunch of files; however I've found that if I say something
> like:
> 
> 	mpg123 /u/louie/jukebox/*.mpg
> 
> things seem to "degrade" after the second or third audio file.  At the
> time, I thought this was some sort of bug with mpg123, so I got into
> the habit of:
> 
> 	for f in /u/louie/jukebox/*.mpg; do mpg123 -q $f; done
> 
> instead, running a new instance for each audio file.  This continues to
> be what I do on my system at work which has thsi version of the
> guspnp driver:
> 
> VoxWare Sound Driver:3.5-alpha8-970706 (Sun Jul  6 01:23:34 PDT 1997 Amancio 
> Hasty@rah.star-gate.com)
> 
> with a GUS PnP board.
> 
> Ok, so far so good.  On my system at home, I've been tracking the
> sound driver release pretty closely and have guspnp16 running now.
> Lately, I've not been using the "jukebox" audio too much at home, and
> haven't really been paying attention.  
> 
> Over the last few days, however, I've noticed that when I run mpg123
> to play an audio sample, I get this weird distortion - sort of a
> fluttering effect, almost with an echo (which might be the same sample
> replayed, or non-sync between the left and right channels, not sure).
> It happens repeatedly, and occurs in the same place in the audio
> playback each time.  I don't think it's a decoding problem with
> mpg123; if I invoked
> 
> 	mpg123 -s foo.mpg | pcmplay
> 
> instead, then the playback either occurs with no problems or fewer
> problems in different places.  I'd fiddled around with ktrace and
> some debug printfs in mpg123 to see if there's something weird
> going on with the size of the write()'s being done at the time
> that the distortion occurs, but I haven't seen anything obvious.
> 
> I'm begining to think that the original problem I saw (playing multiple
> files) and this latest problem (distortion during a file playback) are
> the same sort of thing, but just happening sooner.  It's almost as if
> there is some de-synchronizing thing happening in the sound driver
> after sustained writes which gets cleared or reset when the device is
> closed and reopened.
> 
> I've seen the same thing happen using the 'xaudio' command that
> was recently mentioned as part of a GUI mpeg audio player, so I don't
> think it's the software.
> 
> Sorry about the lack of further detail - what should I do to try to
> narrow down the cause of this?  I've got a bunch of the older
> sound drivers, and if it's useful, I can build a kernel with one of
> the older ones and see if it happens again.  It would be helpful to
> know where significant changes occured so I can minimize the number
> of reboots.  Or perhaps some debug messages that I could corrolate with
> the distorted audio?
> 
> Sorry for bringing this up so late in the process, but it was hard to
> know where the problem lies and I've run out of easy things to try..
> 
> I'm running a GUS PnP, and fairly recent 3.0-current.
> 
> louie
> 





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