[pulseaudio-discuss] HOWTO create a sink/source device for local OS use?

[Maarten Bosmans]

2011/10/9 Rémi Denis-Courmont <remi at remlab.net>:
> Le dimanche 9 octobre 2011 17:13:00 Chris, vous avez écrit :
>> I haven't found a sort of one-liner example for this yet and I know it's
>> possible, but I'm being a bit dense following the FAQ.
>>
>> What I want is a 'virtual audio cable' local to the OS for two applications
>> to use.
>>
>> I want a device created that is a sink and a source.
>
> The loopback plugin does that...

module-loopback is sorta the other way around: it works like an
application that connects a sink to source. The OP asked for a
sink/source pair that connects two apps.

>> I want application one to use the device for its audio output
>>
>> I want application two to use the device for its audio input.
>>
>> A functional equivalent of line-out to line-in of two devices.
>
> ...but it might be easier to rely on the monitoring source of your default
> sink instead. You can either monitor one specific sink input, or the whole
> sink.

Use a null sink to play audio to and its monitor to record from.
See http://www.pulseaudio.org/wiki/Modules#module-null-sink for no
further information.

2011/10/9 Chris <kc2rgw at gmail.com>:
> A functional equivalent of line-out to line-in of two devices.
>
> 44100 would be ideal for the sample rate for both ends
>
> The application is for ham radio DSP of the stream so as little mangling of
> the stream as possible is highly desirable.  Lossy transcoding would hurt
> the signal quality.

Are you required to use pulse input/output of the applications? Can't
you just pipe them together?
Pulse can certainly be configured not to touch the audio with
resampling/mixing, but if you insists in doing so, why even bother
with all the capabilities pulseaudio provides?

Maarten