Bitphase

A modern web-based chiptune tracker for composing on retro sound chips. A project can hold several songs, and each song uses its own chip.

• AY-3-8910 / YM2149F - ZX Spectrum, MSX, Atari ST, and other 8-bit machines
• 2A03 / 2A07 - NES / Famicom (experimental). Each song is NTSC, PAL, or Dendy

User documentation lives in docs/ (pnpm docs:dev).

• Canvas-based pattern editor with order list
• Field-based editing with selection, copy/cut/paste, and magic paste
• Virtual channels - map multiple pattern columns onto a single hardware channel
• Transpose, increment/decrement, and channel swap editing tools
• AY auto envelope and envelope-as-note modes
• Customizable keybindings

• AY/YM instrument editor with tone, noise, envelope, and sample playback
• Timer effects (waveform, PWM, and related AY timer instruments)
• NES instrument editor for the five 2A03 channels: two pulses, triangle, noise, and DPCM
• Tables (known as Ornaments in Vortex Tracker 2)
• Built-in instrument presets
• Instrument preview playground

• Play, pause, play from cursor, play pattern, and solo/mute controls
• Real-time channel oscilloscopes
• MIDI keyboard input for note entry

• Open and save Bitphase projects (.btp)
• Import ProTracker 3 (.pt3), Vortex Tracker 2 (.vt2), TAYM (.taym), and PSG (.psg)
• Import FamiTracker (.ftm) and 0CC-FamiTracker (.0cc) as a 2A03 song, and Dn-FamiTracker (.dnm) when the module is NES or NES plus Sunsoft 5B. A Sunsoft 5B module also adds an AY song. Other expansion chips are left out of .ftm / .0cc imports and rejected for .dnm
• Export WAV for any project, PSG / TAYM / SNDH for AY songs, VGM for AY and NES (at most two of each), and NSF when the project has at most one AY song and one NES song
• AY timer effects are rendered in WAV and written into TAYM and VGM. PSG and SNDH stay one register frame per interrupt
• Several AY songs export as a ZIP of PSG or TAYM files
• Command-line export: pnpm btp-to-wav, pnpm btp-to-psg, pnpm btp-to-taym

• Undo/redo with labeled history
• Lua user scripts for batch edits on selections
• Automatic project backup with recovery on reload
• Custom themes and appearance settings

• Node.js (v18 or higher; v20 recommended)
• pnpm (v10.11.0 or higher)
• Emscripten SDK - required for building WebAssembly modules (AY and NES)
• Git submodules - the Ayumi emulator lives in external/ayumi. NES APU sources ship in external/nsfplug

1. Download and install Emscripten from emscripten.org
2. Set the EMSDK environment variable to point to your Emscripten installation
3. Ensure emcc is available in your PATH

1. Clone the repository

   git clone --recurse-submodules https://github.com/paator/bitphase.git
   cd bitphase

   If you already cloned without submodules:

   git submodule update --init --recursive

2. Install dependencies

   pnpm install

3. Start the development server

   pnpm dev

   This builds the WASM modules (Ayumi + NES) and starts Vite. You can also run pnpm build:wasm on its own when the C sources change.

4. Open your browser

   Navigate to http://localhost:5173 (or the port shown in the terminal)

• pnpm dev - build WASM and start the development server with hot module replacement
• pnpm build - build WASM, the tracker production bundle, and the docs site into dist/
• pnpm build:wasm - build only the WebAssembly modules (public/ay/ayumi.wasm, public/nes/*.wasm)
• pnpm docs:dev - run the VitePress docs site locally
• pnpm docs:build - build docs into dist/docs
• pnpm preview - preview the production tracker build locally
• pnpm check - run TypeScript and Svelte type checking
• pnpm test - run tests in watch mode
• pnpm test:run - run tests once
• pnpm btp-to-wav - export a .btp project to WAV from the command line
• pnpm btp-to-psg - export a .btp project to PSG from the command line
• pnpm btp-to-taym - export a .btp project to TAYM from the command line

bitphase/
├── cli/                     # Command-line tools (btp-to-wav, BTP loading)
├── docs/                    # User docs (VitePress) and format specs
├── external/
│   ├── ayumi/               # AY-8910 emulator C source (git submodule)
│   └── nsfplug/             # NES APU C sources compiled to WASM
├── public/                  # Static assets and runtime audio code
│   ├── audio/               # AudioWorklet processor
│   ├── ay/                  # AY runtime and ayumi.wasm
│   ├── nes/                 # 2A03 runtime and nes_apu.wasm
│   ├── tracker/             # Shared tracker playback pipeline
│   ├── fonts/
│   └── worklet/
├── src/
│   ├── app.css              # Global styles
│   ├── main.ts              # App entry point
│   ├── App.svelte           # Root component
│   ├── demo/                # Bundled demo songs (.btp)
│   ├── presets/             # Built-in instrument preset JSON files
│   └── lib/
│       ├── chips/           # Chip implementations and registry
│       │   ├── ay/          # AY-8910 (schema, adapter, renderer, processor)
│       │   ├── nes/         # 2A03 (schema, adapter, renderer, processor)
│       │   └── base/        # Shared chip interfaces
│       ├── components/      # Svelte UI components
│       │   ├── AppLayout/
│       │   ├── Menu/
│       │   ├── Song/        # Pattern editor and song view
│       │   ├── Instruments/
│       │   ├── Modal/
│       │   ├── Settings/
│       │   ├── Tables/
│       │   ├── Theme/
│       │   ├── History/
│       │   ├── Details/
│       │   ├── Audio/
│       │   └── ...          # Shared UI primitives (Button, Input, etc.)
│       ├── config/          # Menu, keybindings, settings, themes, export formats
│       ├── models/          # Domain models (project, song, history, virtual channels)
│       │   ├── pt3/         # PT3 tuning tables
│       │   └── song/        # Song model utilities
│       ├── presets/         # Preset loading utilities
│       ├── services/        # Business logic
│       │   ├── app/         # Menu actions and app context
│       │   ├── audio/       # Playback and AudioWorklet bridge
│       │   ├── backup/      # Autobackup
│       │   ├── file/        # Import/export (BTP, PT3, VT2, TAYM, PSG, FTM, DNM, WAV, VGM, SNDH)
│       │   ├── history/     # Undo/redo diff tracking
│       │   ├── midi/        # MIDI input
│       │   ├── modal/
│       │   ├── pattern/     # Pattern editing, navigation, clipboard
│       │   │   └── editing/ # Field-based editing strategies
│       │   ├── project/     # Project management and migration
│       │   ├── theme/
│       │   └── user-scripts/  # Lua user scripts
│       ├── stores/          # Reactive state (Svelte 5 runes, .svelte.ts)
│       ├── types/
│       ├── ui-rendering/    # Canvas-based pattern editor and order list
│       └── utils/
└── tests/                   # Tests mirroring src/ structure
    ├── fixtures/
    ├── lib/
    ├── public/              # Tests for public/ runtime scripts
    └── psg/

I (Pator) use AI tools as a coding assistant on Bitphase. I design the features, review the changes, and understand the code that ships. This project is not vibe-coded.

Bitphase is MIT licensed. Third-party software distributed with the app is listed in public/THIRD_PARTY_NOTICES.txt. The running app links to that file from About.