usb-camera-webui

Live MJPEG video feed from a USB webcam, served through a minimal web UI, running on a Raspberry Pi 5.

Quick start

# Install dependencies
sudo apt install -y python3-opencv python3-v4l2

# Run directly
python3 -m camera.app --host 0.0.0.0 --port 8080

Open http://localhost:8080 in a browser. Faces visible in the camera view are marked with green rectangles.

Systemd service

The app runs natively on the Pi via a systemd unit.

Install

# Install dependencies
sudo apt install -y python3-opencv python3-v4l2

# Copy the service unit
sudo cp camera-webui.service /etc/systemd/system/
sudo systemctl daemon-reload
sudo systemctl enable --now camera-webui

Check status

sudo systemctl status camera-webui
journalctl -u camera-webui --follow

Uninstall

sudo systemctl disable --now camera-webui
sudo rm /etc/systemd/system/camera-webui.service
sudo systemctl daemon-reload

Architecture

┌──────────────┐    ┌──────────────┐    ┌──────────┐
│  V4L2 mmap   │───▶│  capture.py  │───▶│  MJPEG   │
│ (V4L2 API)   │    │  + face det. │    │  server  │
└──────────────┘    └──────────────┘    │  :8080   │
                                        └──────────┘
                                               │
                                         ┌─────▼─────┐
                                         │  Browser  │
                                         │ (MJPEG img)│
                                         └───────────┘

• capture.py opens /dev/video0 via V4L2 mmap buffers, dequeues MJPEG frames in a background thread, runs face detection (haar cascades, downscaled for speed), draws green rectangles, and stores the processed frame.
• mjpeg.py serves the MJPEG stream (multipart/x-mixed-replace) via Python's built-in http.server with threading. Only new frames are sent.
• app.py is the entry point: argument parsing, signal handling, and server launch.

Hardware

Item	Details
Camera	Logitech C505 HD Webcam (046d:08e3)
Device	/dev/video0 (USB/UVC)
Format	MJPEG 1280×720
Board	Raspberry Pi 5, Debian 12 (bookworm)

Dependencies

• python3-opencv — OpenCV for face detection (haar cascades, JPEG encode/decode)
• python3-v4l2 — V4L2 Python bindings for camera access
• No pip packages needed