Multiple Apps Accessing Audio

[anmol10]

I was wondering if anyone had tried having multiple applications accessing the audio sub-system on the SL6000 (or any other Zaurus).

You would want something like this is if you want to play mp3's and do VOIP at the same time, or maybe record your VOIP conversations using a console app.

Most desktop Linux distributions allow for mixing of serveral audio sources. From what I gather, this may be enabled in hardware, or may rely on applications like aRTs or ESD to combine the channels, so you can play games and mp3's at the same time. On the Zarus, trying this throws a "/dev/dsp busy" error. I tried searching for esd or arts (ps axu | grep arts) but they don't seem to be running on the Zaurus.

I was wondering if people had tried this sort of a thing or had suggestions about it. I would have to read more about these and see if they could be cross-compiled for the Z.

Thanks,
-Anmol

[lpotter]

The standard 2.4 kernel does not allow sharing (mixing) the audio device among applications.  It can be gotten around by using a sound server, such as ESD, or arts, or QSS.
The newer qt/e 2.3.x has QSS. But it takes the applications to register itself as a QSS client and send bytes to it.

The 2.6 kernel with ALSA, allows the device to mix, I believe.

[anmol10]

Thanks. I wanted to access the audio while kphone/VOIP is running, so I can execute my speech feature processing code at the same time.

I ended up adding some multi-threaded code to kphone to open the mic and stream the audio out.