cremuzzi/mpsyt repository overview

⁠How to use this image

docker run -i -t \
    --device /dev/snd \
    --group-add 29 \
    cremuzzi/mpsyt

The flag --device /dev/snd adds your host sound device to the container. Permissions to access /dev/snd are usually granted to the root user or members of the audio group on your system. This container runs by default as the unpriviledged user mpsyt with uid 1000. This is why we need to add the user to the audio group, with the same GID as your host audio group.

The flag --group-add assigns the correct audio GID from your specific host to the mpsyt user inside the container. By default Alpine Linux sets 18 as the audio GID (audio:x:18:) but this value is usually different on your host. Using --group-add allows you to take care of these differences and run your container with the right permissions on /dev/snd.

You can find the audio GID specific to your host by inspecting the /etc/group file. For instance:

awk -F\: '/audio/{print $3}' /etc/group

⁠Change the default sound device

By default the container uses the sound card with id 0. To change this behaviour you can pass it a custom .asoundrc file on run.

For instance, you can create a file named .asoundrc with the following content:

defaults.ctl.card 1
defaults.pcm.card 1

then pass it to the container as a volume like this:

docker run -i -t \
    --device /dev/snd \
    --group-add 29 \
    -v $HOME/.asoundrc:/home/mpsyt/.asoundrc \
    cremuzzi/mpsyt