RNNoise based noise removal plugin for ALSA

5d753ad release 1.0

2 years ago

5d753ad release 1.0

2 years ago


builds.sr.ht status

RNNoise based noise removal plugin for ALSA

alsa_rnnoise provides ALSA with a high-performance denoiser in real-time, perfect for VoIP conferences and calls, streaming, screencasting, and chatting with friends. To hear a demo of RNNoise in action, on your voice or a voice sample, see this page.


alsa_rnnoise depends on alsa-lib and rnnoise. You can get development files for ALSA through a package called libasound2-dev on Debian, alsa-lib-devel on Fedora, or media-libs/alsa-lib on Gentoo. RNNoise might require manual installation, since it is not packaged by many distributions. See the RNNoise README

Please configure RNNoise with --prefix=/usr, or configure PKG_CONFIG_PATH to include the right path for your prefix.

After installing RNNoise and ALSA, building alsa_rnnoise is a standard meson process:

$ meson build  # generates the ``build'' directory
$ ninja -C build
$ sudo ninja -C build install

Build options

Build options are specified via -Doption=value flags to the meson invocation.

ALSA plugin directory location, usually /usr/lib/alsa-lib. Depends on ALSA build time configuration
Whether to static link RNNoise. Enabled by default since RNNoise lacks stable releases.


The plugin defines the following options:

How much of the original audio to mix into the resulting denoised signal, range [0, 1], where 0 means none and 1 means all. The loudness of the audio should be preserved, but this may affect how nice your recordings sound, in terms of comfort noise and speech quality.

There is currently a known bug where if something requests to know the accepted sample rate interval, the plugin reports an empty interval. Please make sure to specify the sample rate as exactly 48000 as seen in the rnnoise PCM below. I’m currently not aware of a way to fix this with ALSAs external plugin API.

pcm.!default {
    type asym
    playback.pcm "cards.pcm.default"
    capture.pcm "plug:rnnoise"
    # there is a short way to add the wet/dry (and other args):
    #     capture.pcm "plug:\"rnnoise:sysdefault,0.5\""
    # without the plug wrapper this becomes ``rnnoise:slave,wetdry'', both
    # of the arguments are optional
    # this is provided by 60-rnnoise.conf, takes two args: slave, wet_dry
    # see 60-rnnoise.conf for the default values


alsa_rnnoise is Free software licensed under the GNU General Public License, version 3.