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Re: gstreamer 0.10



On Wed, 2005-12-14 at 11:35 +0000, Rob Andrews wrote:
> On 14-Dec-2005 11:31.20 (GMT), Rob Andrews wrote:
>  > > Ummm... this is bad.
>  > > Without arts support, how can I concurrently use both arts applications
>  > > (artsdsp OSS and/or KDE applications) and alsa applications (Amarok over
>  > > gstreamer) without having lock problems?
>  > http://alsa.opensrc.org/index.php?page=DmixPlugin
> 
> Sorry, my reply was supposed to be more verbose but I'm running on
> autopilot this morning.
> 
> dmix is an alsa helper for devices that don't support hardware mixing or
> have fixed-frequency codecs (e.g. the 48000Hz fixed-frequency
> Intel/VIA/SIS integrated audio devices). It downmixes and frequency
> scales as required.

Yeah, it does all that, but it's also the way you stop contention of the
sound device[s].  You point _all_ programs that need to output sound at
dmix, and then only dmix needs to talk directly to the sound hardware
through alsa.  This stops eg xmms from blocking helixplayer from
blocking Flash in firefox, etc.

This is what all the other OSs that actually have sound device
arbitration do AFAIK.  On Mac OS X, you _don't_ touch the hardware, you
don't open /dev/dsp, period.  You talk to CoreAudio (or Carbon's
SoundManager), which handles mixing and resampling if required, and
passes all audio to the device.  Which is what we should be doing in
Linux too.  The audio situation without something like dmix arbitration
is just horrific.

Dan



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