Reads MIDI commands from the Faderfox PC4 and control playback volume on Linux via Pulseaudio.

Can probably also be used with any other MIDI device with minimal modification.

Configuration is read from config.json either in the current working directory, in $XDG_CONFIG_HOME/faderfox/ or ~/.config/faderfox/. See config-example.json for an example.

MIDI channels can be mapped to Pulseaudio sinks, sources, sink-inputs or source-outputs by filtering by name or properties. These can be found in the Name: and Properties: fields when running pactl list [sinks|sources|sink-inputs|source-outputs]. If multiple filters are specified, only objects that match all of them will be used.

Note that the actual name of a sink/source may be different from what you see in your normal volume control apps, as those usually display the device.description property.