[pulseaudio-discuss] On-the-fly changing of sinks or sources in combine- and loopback-modules? Sound-distortions at the beginning of module-loopback?

Lennart Poettering lennart at poettering.net
Wed Feb 17 16:23:02 PST 2010

On Thu, 18.02.10 00:09, Peter Kornatowski (pkorn at gmx.net) wrote:

> Hello,
> 1. Is it possible to change the sinks or sources in an already
> loaded module-combine or module-loopback without unloading and
> reloading the module?

Unless otherwise configured module-combine will automatically add all
new hardware sinks to its outputs and drop those which go away. So
this automatism does allow sinks/sources to be added
dynamically/removed dynamically during runtime. However, there is no
user API for that to trigger that in any way but by
unplugging/plugging hardware.

The streams module-loopback uses you can move around with pavucontrol
or a similar tool.

> 2. I also have a problem with sound distortions (mostly much higher
> and "quicker" voice) several seconds after loading the
> loopback-module (source is a bluetooth-headset and sink is my
> soundcard). After some seconds the distortions disappear and
> everything is fine. I found out that reducing the adjust_time
> parameter of the loopback-module (I had to add adjust_time to
> valid_modargs in the source code) also reduces the duration of the
> distortions, but even at adjust_time=1 they remain for about 2
> seconds (and pulseaudio uses much more CPU). Setting it to 0 doesn't
> work at all.

Sounds as if there is something wrong with the device speed. which
causes PA to compensate by resampling things.


Lennart Poettering                        Red Hat, Inc.
lennart [at] poettering [dot] net
http://0pointer.net/lennart/           GnuPG 0x1A015CC4

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