LV2 plugins

LV2 is the open plugin standard of Linux audio. OpenRig hosts LV2 plugins next to its built-in blocks: their controls, ranges, units and switches come from the plugin, and are edited like any other block.

The OS image ships no LV2 plugin: the Amp, Amp + Cab, Pedal, Cabinet and Space blocks work out of the box.

Adding plugins

Copy LV2 bundles (folders ending in .lv2) into /data/pedalboard/lv2 over SSH, make them belong to the app, and restart:

scp -O -r my-plugin.lv2 root@192.168.1.42:/data/pedalboard/lv2/
ssh root@192.168.1.42 'chown -R pedalboard:pedalboard /data/pedalboard/lv2'

The bundles must be built:

• for the board: aarch64 on the Raspberry Pi, x86_64 on a mini PC;
• against a C library no newer than the image’s;
• with the libraries they need present on the image.

The surest way is to build them with the image: add their Buildroot package to the board’s defconfig (see Build from source).

What is supported

• Control ports: numbers, toggles, integers and lists, with their ranges and units.
• Tempo: ports marked as BPM get the preset’s tempo, and plugins following the host transport get it as a time:Position event.
• MIDI: plugins with a MIDI input get the notes and free CCs (see MIDI).
• Host features: URID map and unmap, options, bounded block length, isLive.

Plugins that require another host feature are skipped when the pedalboard starts, rather than loaded half-working. Not provided yet: the worker extension and plugin state, which rules out plugins that load files themselves (LV2 NAM, AIDA-X or IR loaders: use the built-in Amp, Pedal and Cabinet blocks instead) and some plugins that keep an internal state, such as the Dragonfly Hall, Room and Plate reverbs.

Plugins worth trying

Collections whose plugins load with the features above: ZAM, the DPF plugins, the Guitarix GxPlugins, CAPS, x42 (fil4, dpl, tuna, fat1), Calf built without its UI, LSP, Airwindows, TAP and MDA. The Dragonfly Early Reflections plugin loads; its other reverbs do not yet.

On desktop Linux, the app finds the plugins installed on the system, for instance sudo apt install x42-plugins zam-plugins.