What you want is impossible in principle, regardless of PulseAudio
specifically (i.e my statement applies to any kind of sound server with similar
functionality) and ALSA speicifically (i.e my statement applies to any kind of
direct HW access interface).
The point is that for an HW device to function a stream of audio samples must
be sent into it, and the device must be configured WRT sample rate. If a
program takes control of a sound device, no other program can use it - how do
you imagine one program sending 44100Hz samples and at the same time another
program sending 96000Hz samples to the same device ?
So PulseAudio is among other things a sophisticated mixer doing sample rate
conversion when necessary and adding streams with coefficients (i.e. k1 * s1 +
k2 * s2 + ... + kN * sN) from different sources, the coefficients representing
volumes, and sending the resulting stream into the HW device.
I yet to have find out whether PulseAudio can be running using one sound card,
and ALSA directly for another sound card (this is my setup - I have two
physical sound cards).
Regards,
Sergei.
Mon, 8 Sep 2014 16:32:27 -0700 от "Paul A. Steckler" <st...@stecksoft.com>:
>Well, I meant, keep PulseAudio running, but still use ALSA without
>using the PulseAudio server device, which
>other applications may want to use.
>
>-- Paul
>
>On Mon, Sep 8, 2014 at 4:11 PM, Sergei Steshenko
>< steshenko_ser...@list.ru > wrote:
>>
>>
>>
>> Fri, 5 Sep 2014 09:38:54 -0700 от "Paul A. Steckler" < st...@stecksoft.com >:
>>
>> I have an app that uses the ALSA library on Linux.
>>
>> The app calls snd_pcm_open() to open the capture device. Currently,
>> I use "default" as the name of the device. According to "arecord -L", the
>> default device is the PulseAudio server.
>>
>> Is there a way to bypass PulseAudio, and communicate with the
>> hardware directly?
>>
>> I've tried using "sysdefault" and "hw:0,0" as the name of the device,
>> and in both cases, I get an error that the device is busy. Is that because
>> PulseAudio has monopolized the device?
>>
>> -- Paul
>>
>>
>> "Is there a way to bypass PulseAudio" - one can (simply) stop PulseAudio
>> server, e.g.: http://jan.newmarch.name/LinuxSound/Sampled/PulseAudio/ ->
>> http://www.linuxplanet.com/linuxplanet/tutorials/7130/2 .
>>
>> Regards,
>> Sergei.
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