[linux-audio-dev] alsa mixing

[Patrick Shirkey]

Milan Mimica wrote:
> Hello!
> 
> We're designing a new sound subsystem for allegro game programming 
> library, and we would like to take advantages of multiple hardware voice 
> capabilities.
> 
> On linux, ALSA is the only software that possibly could expose API for 
> such a capability, is that right? It is possible to open multiple PCM 
> outputs and play sound at the same time on all of them. The problem is 
> that we miss some basic mixing features, like panning a mono sound on 
> multichannel output for example. A similar feature is implemented as 
> 'route' ALSA plug-in that can be specified in .asoundrc file, but it is 
> not flexible enough.
> 
> So the question is, does ALSA provide such functionality? If not, which 
> library could? Is it possible that linux OS doesn't provide any API to 
> take advantage of such hardware capabilities?
> 

Surely this is a task that is up to the app to handle?

You would have to provide a function to move the mono signal across the 
channel array accounting for volume. It would not be too difficult once 
the base code for the channel handling was in place.



-- 
Patrick Shirkey - Boost Hardware Ltd.
Http://www.boosthardware.com
Http://lau.linuxaudio.org - The Linux Audio Users guide
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