@strudel-daw/engine 🎵

High-Performance Open Source AGPLv3 Audio Engine & IPC Protocol Driver for Strudel Live Coding DAW Systems.

🌐 Powered in Production: @strudel-daw/engine is the core audio engine driving StruDAW (strudaw.com) — the browser-based Digital Audio Workstation for Strudel live coding.

Based on the revolutionary Strudel.cc ecosystem created by Felix Roos & Contributors.

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🌟 Why @strudel-daw/engine? Key Advantages & Features

@strudel-daw/engine bridges the gap between raw live coding pattern evaluation and full-featured Digital Audio Workstations. Built for maximum performance, legal clarity, and professional audio stability:

• ⚡ Ultra-Fast IPC Message Protocol: Fully decouples audio evaluation from host UI rendering via asynchronous JSON-RPC action dispatchers (INIT, EVALUATE, EVALUATE_ALL, STOP, PREVIEW_SOUND, SET_CPS). Keeps the UI silky-smooth at 60 FPS without main-thread jank.
• 🎛️ Zero-Latency WebAudio Tap & Metering: Features a scoped destination tap intercepting AudioNode graphs cleanly. Feeds real-time AnalyserNode FFT visualizers, VU meters, and lossless PCM audio export without master output distortion.
• 🥁 Smart Multi-Phase Sample Prebaking: Two-tier async sample prebaking strategy. Core drumkit banks (Roland TR-808, TR-909, Dirt samples, GM Soundfonts) load instantly for first-paint audibility, while secondary soundfonts and wavetables are deferred to idle windows (requestIdleCallback).
• 🎼 Advanced Multi-Track Mixing & Stack Engine: Evaluates complex multi-track DAW arrangements with per-channel volume gain, spatial panning, mute/solo gating, metronome tick overlays, and dynamic CPS/BPM tempo synchronization.
• 🔊 True One-Shot Preview System: Dedicated preview engine for sample browsers, piano rolls, and tracker views that avoids global scheduler pollution and never interrupts active live jams.
• 🛡️ 100% AGPLv3 Compliant Open-Core: Complete legal transparency under AGPLv3 Section 13 with automated AST compliance auditing tools included.

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🛠️ Quick Start & Usage

Installation

npm install @strudel-daw/engine

Basic Pattern Evaluation

import { init, evaluate, evaluateAll, setCps, stop } from '@strudel-daw/engine';

// Initialize audio context after user interaction (browser autoplay policy)
await init();

// Evaluate a single Strudel live coding pattern
await evaluate('sound("bd sd, hh*4").bank("RolandTR808")');

// Set tempo (120 BPM = 0.5 CPS)
await setCps(0.5);

// Stop playback
await stop();

Multi-Track DAW Arrangement Evaluation

import { evaluateAll } from '@strudel-daw/engine';

const tracks = [
  { code: 's("bd sd")', volume: 0.9, pan: 0, muted: false, solo: false },
  { code: 's("hh*8")', volume: 0.6, pan: 0.2, muted: false, solo: false },
  { code: 'note("c3 e3 g3 b3")', volume: 0.8, pan: -0.2, muted: false, solo: false },
];

// Evaluate all active tracks stacked with DAW BPM and metronome tick
await evaluateAll(tracks, 128, { metronome: true });

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📜 License & AGPLv3 Compliance Notice

This package is licensed under the GNU Affero General Public License v3.0 (AGPLv3).

In compliance with Section 13 of AGPLv3 (Remote Network Interaction), the complete source code of this audio engine, pattern evaluator, and WebAudio bridge is made available publicly under AGPLv3 for the community.

• Production Platform: strudaw.com
• Engine Source: github.com/thevot/strudel-engine
• Upstream Strudel Core: github.com/tidalcycles/strudel
• Official Strudel Site: strudel.cc

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📄 License

GNU AGPLv3 License - Copyright (C) 2026 Felix Roos & Contributors.