Camera Streaming with go2rtc

Introduction

go2rtc is a lightweight camera streaming application that can expose a printer camera through WebRTC. For printer monitoring, this can provide a lower-latency stream than a traditional MJPEG setup while still integrating cleanly with browser-based printer UIs.

This guide installs go2rtc on a Raspberry Pi OS based printer host, configures a USB camera stream named chamber, starts go2rtc automatically with systemd, and adds the stream to Mainsail and Fluidd.

By the end, you will have:

• A go2rtc binary installed at /home/pi/go2rtc/go2rtc
• A go2rtc.yaml configuration file defining a chamber camera stream
• A go2rtc systemd service that starts on boot
• A camera entry in Mainsail or Fluidd

Camera Device Access

Crowsnest, camera-streamer, ustreamer, mjpg-streamer, or another webcam service may already be using the camera device. A V4L2 USB camera can usually be opened by only one process at a time. If another service is already using /dev/video0, stop or reconfigure that service before testing go2rtc with the same device.

Supported OS Baseline

This guide targets Raspberry Pi OS Bookworm and Trixie. Older Raspberry Pi OS releases such as Bullseye, Buster, Stretch, and Jessie are legacy baselines for this guide. If your printer host is running an older release, upgrade or re-image to Bookworm or Trixie before following these steps.

Prerequisites

• A printer host running Raspberry Pi OS Bookworm or Trixie
• SSH access to the printer host
• A USB camera available as a Linux video device, usually /dev/video0
• A recent Mainsail or Fluidd installation
• Browser access to the printer host on the same local network

Install FFmpeg

The example stream uses go2rtc’s FFmpeg source to read the USB camera and produce an H.264 WebRTC-compatible stream. Install FFmpeg before configuring go2rtc.

1. Update the APT package index:

   Updating package indexes

   sudo apt update

2. Install FFmpeg:

   Installing FFmpeg

   sudo apt install -y ffmpeg

3. Verify that FFmpeg is available:

   Checking FFmpeg

   ffmpeg -version

   The command should print the installed FFmpeg version and build configuration.

Install go2rtc

Install the go2rtc binary in /home/pi/go2rtc. The commands below use the go2rtc_linux_arm64 release asset, which is the correct binary for 64-bit Raspberry Pi OS.

Choosing the Correct Binary

Use go2rtc_linux_arm64 for 64-bit Raspberry Pi OS and go2rtc_linux_arm for 32-bit Raspberry Pi OS. Other builds are available on the go2rtc releases page.

1. Create the installation directory:

   Creating the go2rtc directory

   mkdir -p ~/go2rtc
   cd ~/go2rtc

2. Download the latest go2rtc binary and save it as go2rtc:

   Downloading go2rtc

   wget -O go2rtc https://github.com/AlexxIT/go2rtc/releases/latest/download/go2rtc_linux_arm64

3. Make the binary executable:

   Making go2rtc executable

   chmod a+x go2rtc

4. Verify the binary exists and is executable:

   Checking the go2rtc binary

   ls -l /home/pi/go2rtc/go2rtc

   The permissions should include executable bits, such as -rwxr-xr-x.

Find Your Camera Device

Before writing the go2rtc stream configuration, identify the Linux video device for your camera and confirm one supported capture mode.

1. List video devices:

   Listing video devices

   ls -l /dev/video*

   A single USB camera is often /dev/video0, but the number can vary.

2. Install the V4L2 utilities:

   Installing V4L2 utilities

   sudo apt install -y v4l-utils

3. Map video devices to physical cameras:

   Listing V4L2 devices

   v4l2-ctl --list-devices

   Use this output to choose the correct video= path for go2rtc.yaml. If multiple cameras are connected, /dev/video0 can change after reboot or after reconnecting USB devices. Stable multi-camera naming with persistent device paths or udev rules is outside the scope of this guide.

4. List the selected camera’s supported formats and resolutions:

   Listing camera modes

   ffmpeg -f v4l2 -list_formats all -i /dev/video0

   If your camera is not /dev/video0, replace /dev/video0 with the device path from the previous step. Use one reported format and resolution for input_format and video_size in go2rtc.yaml.

Configure a Camera Stream

Create /home/pi/go2rtc/go2rtc.yaml with a stream named chamber.

1. Open the configuration file:

   Creating go2rtc.yaml

   nano /home/pi/go2rtc/go2rtc.yaml

2. Add the following configuration:

   go2rtc.yaml

   api:
     listen: ":1984"
     origin: "*"
   
   ffmpeg:
     bin: "ffmpeg"
   
   log:
     format: "color"
     level: "info"
     output: "stdout"
     time: "UNIXMS"
   
   rtsp:
     listen: ":8554"
     default_query: "video&audio"
   
   srtp:
     listen: ":8443"
   
   webrtc:
     listen: ":8555/tcp"
   
   streams:
     chamber: ffmpeg:device?video=/dev/video0&input_format=yuyv422&video_size=1280x720#video=h264#hardware

The chamber stream reads /dev/video0 as a V4L2 camera, requests yuyv422 input at 1280x720, and asks FFmpeg/go2rtc to produce H.264 video. The chamber stream name is used later in go2rtc, Mainsail, and Fluidd.

Hardware H.264 Encoding

The #hardware option depends on hardware and FFmpeg/go2rtc support. Raspberry Pi 4 lists H.264 encode support in its product brief. Raspberry Pi 5 lists HEVC decode support, but not H.264 encode. If #hardware causes startup errors or unusable CPU/video behavior, remove #hardware and retest. If your camera can already provide H.264 directly, consider using a source that can be copied with #video=copy instead of transcoding.

Additional Cameras

To add another camera, duplicate the chamber: entry under streams: with a new stream name and device path, such as nozzle: ...video=/dev/video1.... Each camera needs a supported format and resolution, and each device must not already be held by another process.

Test go2rtc

Before creating the systemd service, run go2rtc in the foreground so configuration errors are visible immediately.

1. Start go2rtc manually:

   Starting go2rtc manually

   /home/pi/go2rtc/go2rtc -config /home/pi/go2rtc/go2rtc.yaml

2. Open the go2rtc WebUI in a browser:

   go2rtc WebUI

   http://<printer-ip>:1984

3. Select the chamber stream link.

The video should start after a short delay. Stop the foreground process with CTRL-C before continuing.

Common errors at this stage:

• permission denied: the binary is not executable, or the camera device permissions are wrong.
• no such file or directory: the binary path, config path, or camera path is wrong.
• FFmpeg format errors: input_format or video_size is not supported by the camera.
• Hardware encoder errors: remove #hardware from the stream line and test again.

Start go2rtc on Boot

Create a systemd service so go2rtc starts automatically when the printer host boots.

1. Create the service file:

   Creating the go2rtc service

   nano /home/pi/go2rtc/go2rtc.service

2. Add this unit:

   go2rtc.service

   [Unit]
   Description=go2rtc
   After=network.target
   
   [Service]
   Type=simple
   WorkingDirectory=/home/pi/go2rtc
   ExecStart=/home/pi/go2rtc/go2rtc -config /home/pi/go2rtc/go2rtc.yaml
   ExecReload=/bin/kill -HUP $MAINPID
   Restart=always
   RestartSec=5
   User=root
   Group=root
   Environment=PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/bin
   
   [Install]
   WantedBy=multi-user.target

Service User

This service runs as root to avoid inconsistent USB camera permissions on printer hosts. Advanced users can run go2rtc as a less-privileged service user if they also configure the required video-device permissions.

1. Enable the service using the absolute service-file path:

   Enabling go2rtc

   sudo systemctl enable /home/pi/go2rtc/go2rtc.service

2. Reload systemd and start go2rtc:

   Starting go2rtc

   sudo systemctl daemon-reload
   sudo systemctl start go2rtc

3. Check the service state:

   Checking go2rtc service state

   sudo systemctl status go2rtc

To follow service logs while troubleshooting, run:

Following go2rtc logs

sudo journalctl -u go2rtc -f

Configure Mainsail

Mainsail includes a WebRTC (go2rtc) webcam service for go2rtc streams.

1. Open Mainsail in your browser.

2. Go to Settings > Webcams.

3. Add a new webcam entry.

4. Configure the webcam with these values:

   • Name: Chamber
   • Service: WebRTC (go2rtc)
   • Stream URL: http://<printer-ip>:1984/stream.html?src=chamber&mode=webrtc
   • Aspect ratio: 16:9 for the sample 1280x720 stream
   • Rotation/flip: Set these to match your camera orientation

The src=chamber parameter must match the stream name in go2rtc.yaml.

HTTPS and Mixed Content

If you access Mainsail over HTTPS, the browser may block an HTTP camera stream as mixed content. This usually appears as a blank camera panel. HTTPS, reverse proxy, and remote-access setup are outside the scope of this guide.

Configure Fluidd

Fluidd includes a native WebRTC (go2rtc) camera type.

1. Open Fluidd in your browser.

2. Go to Settings > Cameras.

3. Add a new camera.

4. Configure the camera with these values:

   • Name: Chamber
   • Type: WebRTC (go2rtc)
   • go2rtc URL: http://<printer-ip>:1984
   • Stream name/source: chamber
   • Aspect ratio: 16:9 for the sample 1280x720 stream
   • Rotation/flip: Set these to match your camera orientation

Fluidd field labels may vary by version. The required values are the go2rtc WebUI URL and the chamber stream name.

Troubleshooting

Check go2rtc Service State

Use systemd to confirm whether go2rtc is running:

Checking go2rtc service state

sudo systemctl status go2rtc

If the service is not active, inspect the logs:

Following go2rtc logs

sudo journalctl -u go2rtc -f

Confirm the Camera Device Path

List available video devices:

Listing video devices

ls -l /dev/video*

If your camera is not /dev/video0, update the video= parameter in go2rtc.yaml.

Confirm the Camera Format and Resolution

List supported camera modes:

Listing camera modes

ffmpeg -f v4l2 -list_formats all -i /dev/video0

If the configured input_format or video_size is not listed, update the stream line to use a supported mode.

Check for Another Process Using the Camera

Check whether another service already has the camera open:

Checking camera users

sudo fuser /dev/video0

If another process is listed, stop or reconfigure that service before starting go2rtc with the same device.

Remove Hardware Encoding

If go2rtc starts but the stream fails, or FFmpeg reports hardware encoder errors, remove #hardware from the stream line and restart go2rtc:

go2rtc.yaml

streams:
  chamber: ffmpeg:device?video=/dev/video0&input_format=yuyv422&video_size=1280x720#video=h264

Then restart the service:

Restarting go2rtc

sudo systemctl restart go2rtc

Check Browser and Network Access

Open the go2rtc WebUI directly:

go2rtc WebUI

http://<printer-ip>:1984

If the WebUI does not load, confirm the printer host IP address and check that your browser is on the same local network.

Further Reading

• go2rtc releases
• go2rtc README
• go2rtc FFmpeg source documentation
• go2rtc FFmpeg hardware acceleration documentation
• go2rtc V4L2 documentation
• go2rtc Web viewer documentation
• Raspberry Pi 4 product brief
• Raspberry Pi 5 product brief
• Mainsail webcam settings
• Fluidd camera settings