Livi

A library for hosting LV2 plugins.

Note: This is a work in progress and has not yet been full tested.

Supported LV2 Features

LV2 has a simple core interface but is accompanied by extensions that can add lots of functionality. This library aims to support as many features as possible out of the box.

• http://lv2plug.in/ns/ext/urid#map
• http://lv2plug.in/ns/ext/urid#unmap
• http://lv2plug.in/ns/ext/options#options
• http://lv2plug.in/ns/ext/buf-size#boundedBlockLength

Quickstart

Below is an example on how to run the mda EPiano plugin.

let world = livi::World::new();
const SAMPLE_RATE: f64 = 44100.0;
let worker_manager = std::sync::Arc::new(livi::WorkerManager::default());
let features = world.build_features(livi::FeaturesBuilder {
    min_block_length: 1,
    max_block_length: 4096,
    worker_manager: worker_manager.clone(),
});
let plugin = world
    // This is the URI for mda EPiano. You can use the `lv2ls` command line
    // utility to see all available LV2 plugins.
    .plugin_by_uri("http://drobilla.net/plugins/mda/EPiano")
    .expect("Plugin not found.");
let mut instance = unsafe {
    plugin
        .instantiate(features.clone(), SAMPLE_RATE)
        .expect("Could not instantiate plugin.")
};

// Where midi events will be read from.
let input = {
    let mut s = livi::event::LV2AtomSequence::new(&features, 1024);
    let play_note_data = [0x90, 0x40, 0x7f];
    s.push_midi_event::<3>(1, features.midi_urid(), &play_note_data)
        .unwrap();
    s
};

// This is where the audio data will be stored.
let mut outputs = [
    vec![0.0; features.max_block_length()], // For mda EPiano, this is the left channel.
    vec![0.0; features.max_block_length()], // For mda EPiano, this is the right channel.
];

// Set up the port configuration and run the plugin!
// The results will be stored in `outputs`.
let ports = livi::EmptyPortConnections::new()
    .with_atom_sequence_inputs(std::iter::once(&input))
    .with_audio_outputs(outputs.iter_mut().map(|output| output.as_mut_slice()));
unsafe { instance.run(features.max_block_length(), ports).unwrap() };

// Plugins may push asynchronous works to the worker. When operating in
// Realtime, `run_workers` should be run in a separate thread.
worker_manager.run_workers();

Building, Testing, and Running

• Build - cargo build
• Test - cargo test, requires mda LV2 plugins.
• Run livi-jack - cargo run --example livi-jack --release -- --plugin-uri=http://drobilla.net/plugins/mda/EPiano.