[pulseaudio-discuss] How to *record* application without actually playing the sound?

[Daniel Sonck]

On Sunday 15 December 2013 18:42:12 Manuel Reimer wrote:
> Hello,
> 
> it is no problem to record the sound, played by an application, but I
> still have to "listen to this sound". If I mute the application, I can't
> record it.
> 
> Is it possible to, for example, create some kind of "dummy soundcard" to
> let the application play on this device allowing me to record it without
> having to listen to the playback?
> 
> The idea is to decode DRM radio received by an SDR device. I want the
> decoder application to "record" the digital DRM stream but only want to
> listen to the decoded audio.
> 
> Thank you in advance.
> 
> Greetings,
> 
> Manuel
> 
> _______________________________________________
> pulseaudio-discuss mailing list
> pulseaudio-discuss at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/pulseaudio-discuss

Well, it's quite easy. The module you're looking for is called a null-sink 
http://www.freedesktop.org/wiki/Software/PulseAudio/Documentation/User/Modules/#index3h3

You can either load the module:

pacmd load-module module-null-sink

or you can predefine it in your default.pa file, if you intend to use this 
frequently.

Daniel