SoundCutter

SoundCutter is a browser-based audio cutter and voice effects tool built with SvelteKit, WaveSurfer.js, Tone.js, and FFmpeg.wasm. You can upload or record audio, create regions, preview per-region effects, and export each region as MP3 or as a ZIP bundle.

Features

• Upload MP3, WAV, OGG, and AIFF files
• Record audio directly from the microphone
• Create, rename, trim, and keyboard-navigate waveform regions
• Apply per-region effects and presets with live preview
• Export all regions as 192 kbps MP3 files
• Download exports individually or as a ZIP archive

Privacy and Data Handling

• Audio processing happens locally in the browser.
• User-created presets are stored in localStorage.
• No server upload flow is built into this app.
• The FFmpeg core bundle is downloaded on demand from https://unpkg.com/@ffmpeg/[email protected]/dist/esm the first time you export or convert AIFF audio.

Supported Browsers

• Best supported: current desktop Chromium-based browsers
• Expected to work: current Firefox and Safari, but they are not the primary validation target
• Microphone recording requires a browser with MediaRecorder and getUserMedia support

Tooling

• Node.js 22.12.0 or newer
• pnpm 10.21.0

Development

pnpm install
pnpm check
pnpm test
pnpm build
pnpm dev

Usage

1. Upload an audio file or record a voice clip.
2. Drag on the waveform to create one or more regions.
3. Select a region to rename it, adjust timing, and apply effects or presets.
4. Preview dry playback or effect playback.
5. Export all regions and download the MP3 files individually or as a ZIP.

Deployment Note

This repository is a public app source repo, not a published npm package. If you deploy it, make sure your host serves the app with the cross-origin isolation headers required by FFmpeg.wasm:

• Cross-Origin-Embedder-Policy: require-corp
• Cross-Origin-Opener-Policy: same-origin

The local Vite dev server already sets these headers.

Project Files

• src/lib/components contains the UI
• src/lib/audio/ToneEffects.ts contains the active effects engine
• src/lib/stores contains app state
• .github/workflows/ci.yml runs the release checks

License

• Project license: MIT. See LICENSE.
• Third-party dependency licenses: THIRD_PARTY_LICENSES.md.