[alsa-devel] Opening a PCM device in shared mode
sayem64 at gmail.com
Sun Nov 20 09:54:30 CET 2011
I am a beginner in ALSA API. I am developing a sound application where I
need to open a PCM device for recording/playback audio data. I want to
open this device in shared mode so that other applications can use the
same device. I have downloaded the example ALSA program from here
and run it on my PC. It works fine when it runs alone. But when I start
a song on a media player and then run this example, it shows an error
|Playback open error: Device or resource busy
Looking at the source code of this example I could say that
at line 882 is throwing this error. It finds the device busy since
another process is currently using it. I also tried the reverse way -
first started the example then tried to start a song. In this case the
media player stays idle, showing "idle" just beside the progress bar (I
am using Banshee). I am assuming that snd_pcm_open gains exclusive right
of the device resource so that no other process can use it.
But I don't want that. I want to play sound to a audio device without
requiring any exclusive rights so that other processes in the PC can
share the same device for outputting audio data.
How can I do that? How can I open a PCM device so that other processes
can also share the same device?
P.S. : I have two sound cards on my system, one is built-in in
motherboard, another one is a USB Card. I tried opening the USB (by
specifying "plughw:1,0" as argument in the snd_pcm_open) card and then
got this error.
Thank you in advance.
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