Remote Microphone (WebRTC + FastAPI)

Stream a microphone from one machine to another over the network and use it as a mic input on Windows.

How it works

Sender captures mic → WebRTC → Receiver → VB-CABLE → apps see it as a microphone

FastAPI is only used for signaling. Audio is handled by WebRTC.

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Requirements

Python deps

Install:

pip install -r requirements.txt

System deps

• Install ffmpeg
• On Windows (receiver): install VB-CABLE

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Setup

1. Start receiver (Windows)

Edit nothing unless your VB-CABLE device name is different.

Run:

python receiver.py

Server starts on port 8000.

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2. Start sender (any machine)

Edit SERVER_URL in sender.py:

SERVER_URL = "http://RECEIVER_IP:8000"

Then run:

python sender.py

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Use as microphone

On the Windows receiver machine:

• Open Discord / Zoom / Teams / etc.
• Select VB-CABLE output/recording device as your microphone

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Notes

• Works best on a local network
• Latency is low (~tens of ms)
• Audio is mono 48kHz
• No authentication (LAN use only)

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Troubleshooting

No audio

• Check VB-CABLE is installed
• Verify correct device name in receiver.py
• Make sure sender is connected (no errors in console)

Wrong device

Print devices:

import sounddevice as sd
print(sd.query_devices())

Update device name in receiver.

Choppy audio

• Ensure stable LAN connection
• Avoid WiFi if possible
• Reduce CPU load

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Limitations

• Single sender only
• No reconnect logic
• No NAT traversal (LAN only)
• Relies on virtual audio cable (not a native driver)