[Sugar-devel] Pulse audio on Fedora 11

[Jim Simmons]

My own two cents on Pulse Audio on Fedora 11: it doesn't work.

I recently upgraded my Freevo box to Fedora 11 and had MANY sound
related issues that were directly or indirectly caused by pulse audio.
 Freevo of course uses mplayer to play movies.  It needs to sync the
audio and the video to do that so any problems with the audio affect
the playback of the movies.  The picture would freeze every so often,
etc.  I tried several recommendations I found through google.  (This
is a WIDELY reported problem).  The only thing that seemed to work was
removing pulse audio and enabling oss.  That only *kind of* worked.
The movies played smoothly but everyone's voices were a bit like Alvin
and the Chipmunks.  Just a tiny bit, but noticeable.  I ended up
reinstalling Fedora 10.

I still have Fedora 11 on the box that I use to develop my Activities.
 I don't play movies on that box (much) so the Pulse Audio problems
are tolerable.

It looks like Fedora 10 did use pulse audio by way of ALSA and OSS
emulation without problems.

James Simmons

> Date: Tue, 08 Sep 2009 11:46:26 -0400
> From: Paul Fox <pgf at laptop.org>
> Subject: Re: [Sugar-devel] [Csnd] Re: Re: Re: Re: csound on Fedora 11
>        and     rawhide
> To: Peter Robinson <pbrobinson at gmail.com>
> Cc: Art Hunkins <abhunkin at uncg.edu>, csound at lists.bath.ac.uk,   Sugar
>        devel <sugar-devel at lists.sugarlabs.org>
> Message-ID: <5091.1252424786 at foxharp.boston.ma.us>
> Content-Type: text/plain; charset="us-ascii"
>
> peter wrote:
>  > On Tue, Sep 8, 2009 at 4:23 PM, Art Hunkins<abhunkin at uncg.edu> wrote:
>  > > Victor, I understand you to be saying that pulseaudio exhibits more latency
>  > > than ALSA.
>  > >
>  > > If this is so, why are we making pulseaudio the default for SoaS - where
>  > > most audio will be realtime?
>  >
>  > Because that's what Fedora and most other distros are moving to. Also
>
> i think using pulseaudio on a distro which is almost by definition
> aimed at under-powered machines is a mistake.  it's a very expensive
> subsystem, performance-wise.  i seem to recall seeing it take 10% of
> a 1Ghz system.
>
> paul
>
>  > it does add more latency but not enough that most users will notice.
>  > Even if you use alsa it will connect to the alsa pulse audio provider
>  > which will basically add even more latency Csound -> PA alsa provider
>  > -> PA -> ALSA -> kernel.
>  >
>  > It works fine in most cases even for VoIP. What requires such low
>  > latency as to be an issue in an environment such as a learning one.
>  > Will the children notice a few milliseconds?
>  >
>  > Peter