OpenVoiceChanger

Real-time AI voice changer web application.
Route a microphone through ONNX or RVC models with a low-latency WebSocket audio pipeline.

Quick Start • Model Support • API • Configuration • 한국어 • 日本語

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Features

Realtime studio

• Real-time voice conversion with binary WebSocket streaming and AudioWorklet
• ONNX and RVC model support, plus a model-free DSP mode (pitch shifting and effects with no checkpoint loaded)
• Live pitch and formant shifting, F0 method selection (PM / Harvest / Crepe / RMVPE / FCPE), and RVC advanced controls (index rate, RMS mix, protect)
• 12-effect server-side DSP rack: noise gate, robot, whisper, telephone, distortion, bitcrush, chorus, echo, reverb, tone EQ, compressor, output gain — all streaming-safe with per-connection state
• 16 built-in voice presets (Chipmunk, Deep Voice, Robot, Ghost, Telephone, Stadium, …) plus save/delete for your own presets
• Real-time spectrum visualizer, VU meters with peak hold, latency sparkline, and a server timing breakdown (model / DSP / network)
• Output recorder — capture the converted voice and download it as WAV

Offline converter

• Upload a whole audio file (wav / mp3 / flac / ogg / m4a) and render it through the active model + effect chain to a downloadable WAV

Management

• Drag-and-drop model upload (.pth / .pt / .onnx + companion .index files), one active model at a time
• Model metadata badges: RVC version, target sample rate, F0 support, index presence, device
• Session settings modal for sample rate, chunk size, and ONNX / PyTorch / GPU / CUDA runtime visibility

Screenshots

Studio

The realtime workspace: live spectrum, device routing, output recorder, VU meters with a model / DSP / network latency breakdown, and pitch, formant, and F0 method controls.

Presets & effects rack

16 one-click voice presets and the 12-effect server-side DSP chain. Everything here works with or without a voice model — enable an effect and it applies to the live stream instantly.

Models

Drag-and-drop upload for RVC / ONNX checkpoints and companion .index files, with metadata badges and one-click activation.

Converter

Render whole audio files through the active model and effect chain, then download the result as WAV.

Settings

Stream defaults plus a live view of what the backend sees: ONNX provider, PyTorch device, GPU, and CUDA.

Quick Start

The commands below assume Windows PowerShell in the repository root.

0. Clone the repository

git clone https://github.com/sioaeko/OpenVoiceChanger.git
cd OpenVoiceChanger

1. Backend setup

python -m venv .venv
.venv\Scripts\Activate.ps1
python -m pip install --upgrade pip
pip install -r backend/requirements.txt
pip install --no-deps git+https://github.com/RVC-Project/Retrieval-based-Voice-Conversion

2. Optional: enable ONNX GPU acceleration

CPU ONNX works with the default requirements. If you want ONNX to use CUDA locally, replace the CPU package with the GPU package:

pip uninstall -y onnxruntime
pip install onnxruntime-gpu==1.23.2

3. Frontend setup

cd frontend
npm install
npm run build
cd ..

4. Prepare model assets

RVC .pth / .pt models need a HuBERT content encoder file.

New-Item -ItemType Directory -Force models\assets | Out-Null

Place the file here:

models/assets/hubert_base.pt

You can override that path with OVC_HUBERT_PATH.

5. Start the app

.venv\Scripts\python.exe -m uvicorn backend.main:app --host 127.0.0.1 --port 8000

Open:

http://127.0.0.1:8000

6. Optional: Vite dev mode

Terminal 1:

.venv\Scripts\python.exe -m uvicorn backend.main:app --reload --host 127.0.0.1 --port 8000

Terminal 2:

cd frontend
npm run dev

Then open http://127.0.0.1:5173.

Model Support

Format	Engine	Notes
.onnx	ONNX Runtime	CPU by default, CUDA if onnxruntime-gpu is installed
.pth / .pt	PyTorch	RVC v1/v2 models, requires hubert_base.pt

Web UI Flow

1. Open the app in your browser.
2. (Optional) Upload and activate a model in the Models tab — without one, the studio runs in pure DSP mode.
3. Pick your input and output devices in the Studio tab.
4. Click Start Voice Changer.
5. Shape the voice live: pitch, formant, F0 method, effect rack, or a one-click preset.
6. Record the output, or render whole files in the Converter tab.

API

Method	Endpoint	Description
GET	/health	Health check
GET	/api/config	Sample rate, chunk size, ONNX runtime info, PyTorch runtime info
GET	/api/models/	List uploaded models
POST	/api/models/upload	Upload a model file
DELETE	/api/models/{name}	Delete a model
POST	/api/models/{name}/activate	Activate a model
POST	/api/models/deactivate	Deactivate the current model
GET	/api/models/active	Get the active model
GET	/api/presets/	List built-in and user voice presets
POST	/api/presets/	Save a user preset
DELETE	/api/presets/{id}	Delete a user preset
POST	/api/convert/	Offline file conversion (multipart upload → WAV)
WS	/ws/audio	Real-time audio streaming

Interactive docs are available at /docs while the backend is running.

WebSocket protocol

1. Connect to /ws/audio
2. Send JSON config: {"sample_rate": 40000, "chunk_size": 4096}
3. Send binary audio frames: [uint32 seq_num][uint32 reserved][float32[] PCM samples]
4. Receive processed audio frames in the same format — the response reserved field carries the server processing time in hundredths of a millisecond
5. Send settings updates such as {"pitch_shift": 3.0, "formant_shift": -2.0, "f0_method": "rmvpe", "effects": {"reverb": {"enabled": true, "size": 0.6, "mix": 0.4}}}
6. Receive periodic status JSON: {"type": "status", "latency_ms": …, "model_ms": …, "dsp_ms": …, "mode": "rvc|onnx|dsp", "effects_active": …}

Configuration

Environment variables use the OVC_ prefix.

Variable	Default	Description
OVC_MODELS_DIR	models	Model directory
OVC_HOST	0.0.0.0	Backend bind address
OVC_PORT	8000	Backend port
OVC_SAMPLE_RATE	40000	Default sample rate
OVC_CHUNK_SIZE	4096	Default chunk size
OVC_CORS_ORIGINS	["*"]	Allowed CORS origins
OVC_LOG_LEVEL	info	Log level
OVC_HUBERT_PATH	models/assets/hubert_base.pt	HuBERT path for RVC
OVC_RMVPE_ROOT	models/assets/rmvpe	Optional RMVPE assets directory
OVC_RVC_STREAM_CONTEXT_SECONDS	1.0	Per-stream RVC context length
OVC_RVC_INDEX_RATE	0.75	Retrieval mix when a matching .index exists
OVC_RVC_FILTER_RADIUS	3	Harvest median filter radius
OVC_RVC_RMS_MIX_RATE	0.25	RMS envelope blend
OVC_RVC_PROTECT	0.33	Consonant protection
OVC_PRESETS_PATH	data/presets.json	User preset storage file
OVC_MAX_CONVERT_SECONDS	600	Max audio length for offline conversion

Project Structure

OpenVoiceChanger/
├── backend/
│   ├── main.py
│   ├── config.py
│   ├── routers/
│   └── services/
├── frontend/
│   ├── public/
│   └── src/
├── models/
├── README.md
├── README_KR.md
├── README_JP.md
└── Makefile

Makefile

The included Makefile is a convenience for POSIX shells or WSL.

Command	Description
make install	Install backend and frontend dependencies
make dev	Run backend and frontend dev servers
make dev-backend	Run backend only
make dev-frontend	Run frontend only
make build	Build the frontend
make clean	Remove build artifacts

Requirements

• Python 3.10+
• Node.js 18+
• npm

License

MIT