Matter Camera Controller Example

Matter Camera Controller Example#

This example application demonstrates the CHIP Camera Controller running on a Linux platform and explains how to build and run the Camera Controller Example on Linux.

In a typical setup, the Camera Controller app manages a CameraDevice app running on a Raspberry Pi. The CameraDevice captures and encodes the video feed before streaming it through a WebRTC track, while the CameraController receives this video stream and displays it, creating a complete end-to-end camera solution.

Overview#

The example consists of two primary applications:

Camera App (chip-camera-app): This application functions as the Matter accessory. It captures and encodes a video feed, making it available for streaming over a WebRTC connection. It is typically run on a device with a camera, such as a Raspberry Pi.

Camera Controller (chip-camera-controller): This application acts as the client. It commissions the Camera App onto the Matter network, discovers it, and receives and displays the video stream.

Building the Example Application#

1. Prerequisites#

Before building, you must install the necessary GStreamer libraries and development packages, which are used for video processing and streaming.

sudo apt update
sudo apt install \
  gstreamer1.0-plugins-base \
  gstreamer1.0-plugins-good \
  gstreamer1.0-plugins-bad \
  gstreamer1.0-libav \
  libgstreamer1.0-dev \
  libgstreamer-plugins-base1.0-dev

2. Building the Applications#

  1. Initialize the Build Environment This command configures your shell with the necessary build tools. You only need to run this once per terminal session.

source scripts/activate.sh

  1. Build the Camera App (Device)

Follow the build instructions from examples/camera-app/linux/README.md

  1. Build the Camera Controller (Client)

You can either build the applications for a local Linux machine or cross-compile them for a Raspberry Pi.

Option A: Build for a Local Linux (x86_64)

This is the simplest method for testing the camera pipeline on a single Linux computer.

# Navigate to the examples directory
cd examples/camera-controller/

# Compile the Linux x86‑64 camera‑controller target
./scripts/build/build_examples.py \
    --target linux-x64-camera-controller \
    build

The resulting executable is placed in:

out/linux-x64-camera-controller/chip-camera-controller.

Option B: Cross-Compile for Raspberry Pi (arm64)

To run an application on a Raspberry Pi, you must cross-compile it from an x86_64 host machine. The recommended method is to use the provided Docker build environment to ensure all dependencies are correct.

  1. Pull the Cross-Compilation Docker Image

docker pull ghcr.io/project-chip/chip-build-crosscompile:162

  1. Run the Docker Container This command starts an interactive shell inside the container and mounts your local connectedhomeip repository into the container’s /var/connectedhomeip directory.

docker run -it -v ~/connectedhomeip:/var/connectedhomeip ghcr.io/project-chip/chip-build-crosscompile:162 /bin/bash

  1. Build Inside the Container From within the Docker container’s shell, execute the build script.

cd /var/connectedhomeip

# Required to fix git repository ownership issues inside Docker
git config --global --add safe.directory /var/connectedhomeip
git config --global --add safe.directory /var/connectedhomeip/third_party/pigweed/repo

# Run the build script for the Raspberry Pi (arm64) target
./scripts/run_in_build_env.sh \
  "./scripts/build/build_examples.py \
    --target linux-arm64-camera-controller-clang \
    build"

  1. Transfer the Binary to the Raspberry Pi After the build completes, exit the Docker container. The compiled binary will be available on your host machine in the out/ directory. Use scp to copy it to your Raspberry Pi.

# The binary path on your host machine
# out/linux-arm64-camera-controller-clang/chip-camera-controller

# SCP command to transfer the file
scp ./out/linux-arm64-camera-controller-clang/chip-camera-controller ubuntu@<RASPBERRY_PI_IP_ADDRESS>:/home/ubuntu

3. Running the Live View Demo#

After building the applications using Option A, you can run the full end-to-end example on your Linux machine. You will need two separate terminal windows.

Terminal 1: Start the Camera App (Device)

  1. Launch the chip-camera-app binary.

Clean up any existing configurations (first-time pairing only):

sudo rm -rf /tmp/chip_*

./out/linux-x64-camera/chip-camera-app

Terminal 2: Launch and Use the Camera Controller (Client)

  1. Launch the Controller Start the interactive controller shell.

./out/linux-x64-camera-controller/chip-camera-controller

  1. Commission the Device At the controller’s > prompt, use the pairing command to securely commission the Camera App onto the Matter network.

onnetwork: Specifies pairing over the local IP network.

pairing onnetwork 1 20202021

Wait for the command to complete and confirm that commissioning was successful.

  1. To start a live video stream from your camera, use the liveview start command followed by the nodeID you set during pairing. For example, if your nodeID is 1, you can request a stream with a minimum resolution of 800x600 pixels and a minimum frame rate of 30 frames per second using the command below.

liveview start 1 --min-res-width 800 --min-res-height 600 --min-framerate 30

To see what video formats and resolutions your camera supports, first list the available video devices, then check the formats for your specific device:

# List all available video devices
v4l2-ctl --list-devices

# Check formats for a specific device (replace /dev/video0 with your device)
v4l2-ctl -d /dev/video0 --list-formats-ext

Wave your hand in front of the camera to trigger live view; a video window will appear, confirming that the stream is active.

4. Running the Video Recording Upload Demo#

The Push AV Server acts as the recording destination (like a cloud service) for video clips. The demo shows how a Matter Camera Controller tells a Matter Camera to record a clip and upload it to that server.

The server itself doesn’t control the camera; it’s a passive service that securely receives and stores media. The relationship is established by the controller.

The Server’s Role: The Recording Destination#

The Push AV Server runs in the background, waiting for authenticated devices to push video content to it. The key piece of information it provides is its ingest URL, which, for example, looks like this: https://localhost:1234/streams/1

Think of this server as a secure, private YouTube or Dropbox, but just for your camera’s video clips.

Here is the command to set up a local Push AV Server, using a virtual environment. (recommended)

# Create a virtual environment
python3 -m venv pavs_env

# Activate it
source pavs_env/bin/activate

# Install dependencies
pip install uvicorn fastapi jinja2 cryptography zeroconf pydantic

# Run the server
python server.py --working-directory ~/.pavstest

The Controller’s Role: The Orchestrator#

The chip-camera-controller acts as the “brain” of the operation. It’s what you use to configure the system. It tells the camera where to send its recordings.

This happens in this specific command:

  • Build & run camera application

./scripts/examples/gn_build_example.sh examples/camera-app/linux out/debug
./out/debug/chip-camera-app

  • Build & run chip-camera-controller steps for clip recording & uploading

./scripts/build/build_examples.py --target linux-x64-camera-controller build
./out/linux-x64-camera-controller/chip-camera-controller

  • Pair Camera

pairing code 1 34970112332

  • Video Stream Allocation

cameraavstreammanagement video-stream-allocate 3 0 30 30 '{ "width":640, "height":480}' '{ "width":640, "height":480}' 10000 10000 1 10 1 1 --WatermarkEnabled 1 --OSDEnabled 1

  • Audio Stream Allocation

cameraavstreammanagement audio-stream-allocate 3 0 2 48000 96000 16 1 1

  • Push AV Transport allocation

pushavstreamtransport allocate-push-transport '{"streamUsage":0, "videoStreamID":1, "audioStreamID":2, "endpointID":1, "url":"https://localhost:1234/streams/1", "triggerOptions":{"triggerType":0, "maxPreRollLen":1, "motionTimeControl":{"initialDuration":20, "augmentationDuration":5,"maxDuration":40, "blindDuration":5}}, "ingestMethod":0, "containerOptions":{"containerType":0, "CMAFContainerOptions": {"chunkDuration": 4, "CMAFInterface": 0, "segmentDuration": 6, "sessionGroup": 1, "trackName": "main"}}}' 1 1

Here, the controller is sending the server’s URL to the camera. It’s essentially saying, “When I tell you to record a clip, this is the address you need to send it to.”

The Camera’s Role: The Content Producer#

The chip-camera-app is the device that does the actual work of recording and sending the video. After it receives the configuration from the controller, it waits for a trigger.

This command from the controller is the trigger:

pushavstreamtransport manually-trigger-transport 1 0 1 1

This command means, “Start recording now and upload the clip to the URL I gave you earlier.” The camera then connects to the push_av_server at https://localhost:1234/streams/1 and pushes the video clip.