@waveform-playlist/playout

Tone.js-based PlayoutAdapter for @waveform-playlist/engine — drives playback, recording, and effects on a shared global Tone.js audio context. Used by @waveform-playlist/browser (the React surface). For native Web Audio (no Tone.js), see @dawcore/transport.

Installation

npm install @waveform-playlist/playout

Requires tone (^15.0.0) as a peer dependency — this package doesn't bundle Tone.js, so the version in your app is the one that runs. @waveform-playlist/engine is an optional peer; most consumers pull in both automatically via @waveform-playlist/browser rather than installing this package directly.

Usage

import { createToneAdapter } from '@waveform-playlist/playout';
import { PlaylistEngine } from '@waveform-playlist/engine';

const adapter = createToneAdapter();
const engine = new PlaylistEngine({ adapter });

engine.setTracks(tracks); // ClipTrack[]
engine.play(0);

createToneAdapter() eagerly creates the shared global Tone.js context before building its audio graph, so adapter.audioContext is guaranteed to be the same context the playout's nodes are on.

Audio context is a standardized-audio-context ponyfill

getGlobalContext() / getGlobalAudioContext() return Tone.js's global context, whose rawContext is always a standardized-audio-context ponyfill — not a native BaseAudioContext / AudioContext. This is deliberate: the ponyfill normalizes cross-browser differences (e.g. Firefox AudioWorkletNode / AudioParam).

Consequences for integration:

• getGlobalAudioContext() instanceof window.AudioContext is false.
• The native AudioWorkletNode constructor rejects it — new AudioWorkletNode(getGlobalAudioContext(), 'my-processor') throws TypeError: parameter 1 is not of type 'BaseAudioContext' (same in Chrome and Firefox).

Third-party worklet code should not hardcode the native constructor. Inject the AudioWorkletNode constructor and the module loader (the dependency-injection pattern from chrisguttandin/limiter-audio-worklet — paired with limiter-audio-worklet-processor), or import AudioWorkletNode from standardized-audio-context, so the code works on a native or ponyfilled context. @waveform-playlist/worklets follows this exact pattern:

// caller supplies addModule for whichever context type is in use
await addRecordingWorkletModule((url) => ctx.audioWorklet.addModule(url));

If you genuinely need a native AudioContext, own it yourself via the web-components adapter surface (@dawcore/*), which uses native Web Audio rather than Tone.

License

MIT