[pulseaudio-discuss] using pulseaudio to implement audio policies
lennart at poettering.net
Wed Mar 26 12:40:22 PDT 2008
On Wed, 13.02.08 07:23, Turner, Todd (Todd.Turner at windriver.com) wrote:
> I'm new to PulseAudio and I have a question. I am designing a system
> that needs to implement audio priorities. Each application will be
> able to write to a certain virtual sound device, and I need to
> implement this sort of thing:
> virtual audio device A - high priority
> virtual audio device B - normal priority
> virtual audio device C - low priority
> What needs to happen is when device A is written to, device B and device
> C are muted, when device B is written to C is muted, etc.
> How would I go about doing this with PulseAudio? Can someone point me
> in the right direction? Originally these devices were going to be
> virtual ALSA devices, not sure exactly if PulseAudio handles virtual
> ALSA devices?
If the virtual ALSA device is properly implemented, than PA should be
fine accessing them. Unfortunately, the fewest virtual ALSA devices
*are* implemented properly.
You probably should write a small module PA which hooks into the
creation fo streams in PA. And everytime a stream is created or
removed you do you muting/unmuting logic based on the current
state. Should be reasonably easy to do. Unfortunetly however, we don't
have much of a documentation of these internals of PA. Hence: read the
The "glitch-free" brnach in PA SVN now has some basic code to attach
prio info to streams. This might be useful to do proper prio based
Lennart Poettering Red Hat, Inc.
lennart [at] poettering [dot] net ICQ# 11060553
http://0pointer.net/lennart/ GnuPG 0x1A015CC4
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