Lyricron

Every line, right on time.

Create perfectly timed lyrics while you listen: play a track, tap along, and export a ready-to-use .lrc file. Load a local audio (or video) file, add the lyrics, then press Annotate as the song plays to stamp each line.

100% private and works offline: no account, no upload, nothing ever leaves your device. Everything (including fonts) runs locally in the browser.

Support

Lyricron is free and open source. If it saves you time, you can support ongoing development here:

Features

• Load media: drop an audio or video file anywhere on the page, or use the file picker (only the audio plays).
• Add lyrics: type or paste them by hand, import a .txt/.lrc file, or fetch synced lyrics from LRCLIB.
• Paste timed LRC: pasting timed lyrics into the plain-text field detects them and asks whether to load them as timed lyrics or convert to plain text.
• Annotate: stamp each line as the song plays, with blank-line support for instrumental gaps.
• Fine-tune: inline timestamp editing, ±50 ms nudging per line, shift-all, and undo/redo.
• Keyboard-driven: annotate, play/pause, seek, and jump between timed lines without the mouse (see Shortcuts below).
• Output: preview mode, per-line timestamps, and copy/export to .lrc.
• Extras: playback speed control, dark/light/system theme, and project auto-save.

Tech stack

• React 19 + TypeScript
• MUI with styled components
• Playwright
• oxlint

Getting started

Requires Node.js (see .nvmrc).

nvm use
npm ci
npm run dev

Open the URL printed by Vite (default http://localhost:5173).

Scripts

• npm run dev: start the Vite dev server.
• npm run build: type-check (tsc -b) and build for production.
• npm run lint: lint with oxlint.
• npm run test: run unit tests, then end-to-end tests.
• npm run test:unit: run Vitest unit tests only.
• npm run test:e2e: run Playwright end-to-end tests only.

Keyboard shortcuts

Defaults, configurable via .env (see .env.example):

• Space: Play / Pause.
• Enter: Annotate the next line.
• ← / →: Seek back / forward by 5 s (hold Shift for 1 s).
• Ctrl/⌘ + ← / →: Previous / next timed line.
• [ / ]: Shift the last line by -50 ms / +50 ms.
• Ctrl/⌘ + Z / Ctrl/⌘ + Shift + Z: Undo / Redo.
• Shift + /: Show the shortcuts help.

To customize, copy .env.example to .env (or .env.local) and set any VITE_SHORTCUT_* value to a KeyboardEvent.code string (for example KeyA, Space, ArrowLeft), then restart the dev server. Empty values fall back to the defaults above.

Testing

Unit tests cover the pure logic in src/lib, and end-to-end tests drive the full app in a real browser. See the scripts above to run them.

Privacy

Lyricron never sends your audio, lyrics, or timestamps anywhere. It is a static single-page app with no backend, no analytics, and no external requests (fonts are bundled locally).