[Openal-devel] Patch for intermittent ALSA capture

[Chris Robinson]

On Tuesday 06 May 2008 03:41:32 pm Jason Daly wrote:
> I discovered that I can't call alcCaptureStart(), then alcCaptureStop(),
> then alcCaptureStart() again.  This is with oal-soft 1.3.253, using the
> ALSA backend.
>
> I attached a patch that fixes it.  Basically, you just need to call
> snd_pcm_prepare before each call to snd_pcm_start (not just the first
> one).  If you don't do this, the second and subsequent start calls
> return an error, which snd_strerror reports as "File descriptor in bad
> state".

Hmm, that's odd. I don't remember having issues on my machine with starting 
and stopping. Though I've had other issues with apps indescriminately setting 
large buffer sizes without concern for hardware caps.. Regardless, I applied 
the fix.

And sorry for being really silent lately. I've been distracted by other 
projects, and I'm not entirely sure what I want/can do with OpenAL Soft (and 
further apologies to Daniel Peacock for not replying to his email).


But on the subject of what to do with OpenAL Soft, I've been wondering about 
splitting out the main mixer so that it runs in a seperate process, and using 
IPC and shared memory so that multiple apps can use a unique context on the 
same device (so, for example, a media player can open a device with openal 
soft, get a context and turn off the uneeded features for faster processing, 
while a game has that same device open with 3d audio + effects, all being 
mixed and output into one ALSA/OSS device). I'm not too sure of how efficient 
I could get a setup like that working, though..