Acknowledgement

This project is a migration from ROS1 to ROS2. The original code was developed by CircusMonkey. I would like to express my gratitude for his contribution.

image2rtsp

This project enables the conversion of a selected ROS2 topic of type sensor_msgs::msg::Image into an RTSP stream, with an anticipated delay of approximately 30-50ms. The generated stream can be utilized for various purposes such as remote control, object detection tasks, monitoring, and more. Please note that the migration process is ongoing, and therefore, the complete functionality of the original package is not yet available.

The development is being carried out on Ubuntu 20.04 with ROS2 Foxy.

Dependencies

• ROS2 foxy

• gstreamer libs:

sudo apt-get install libgstreamer-plugins-base1.0-dev libgstreamer-plugins-good1.0-dev libgstreamer-plugins-bad1.0-dev libgstrtspserver-1.0-dev gstreamer1.0-plugins-ugly gstreamer1.0-plugins-bad

Install

• Navigate to the root directory, create a new directory named ros2_ws/src, and then change the current working directory to ros2_ws/src:

  cd
  mkdir -p ros2_ws/src
  cd ros2_ws/src/
  

• Clone the package:

  git clone https://github.com/45kmh/image2rtsp.git
  

• Adjust parameters.yaml according to your needs:

  gedit ~/ros2_ws/src/image2rtsp/config/parameters.yaml
  

Example ROS2 Image topic stream

topic: "/color/image_raw"  # The ROS2 topic to subscribe to
mountpoint: "/back"        # Choose the mountpoint for the rtsp stream. 
                           # This will be able to be accessed from rtsp://<server_ip>/portAndMountpoint
caps: "video/x-raw,framerate=10/1,width=640,height=480"
                           # Set the caps to be applied after getting the ROS2 Image and before the x265 encoder.
bitrate: "500"
port: "8554"
local_only: True           # True = rtsp://127.0.0.1:port (The stream is accessible only from the local machine)
                           # False = rtsp://0.0.0.0:portAndMountpoint (The stream is accessible from the outside) 
                           # For example, to access the stream running on the machine with IP = 192.168.20.20,
                           # use rtsp://192.186.20.20:portAndMountpoint
                           # True = rtsp://127.0.0.1:portAndMountpoint (The stream is accessible only from the local machine)

• Save your configuration and navigate to image2rtsp colcon root, source and build the package:

  cd ~/ros2_ws/
  colcon build --packages-select image2rtsp
  

Run

• Source install and launch the package:

  source install/setup.bash
  ros2 launch image2rtsp image2rtsp.launch.py 
  

  Don't use ros2 run!

Check the stream

To check the stream, follow the instructions for gstreamer, mpv or VLC provided by CircusMonkey or use python script provided in this package (ensure before that the open-cv library is installed, if not pip install opencv-python). Open new terminal, ensure that the topic to be converted exists and the RTSP stream is running. Then:

gedit ~/ros2_ws/src/image2rtsp/python/rtsp.py

Replace the rtsp://127.0.0.1:8554/back with your server's IP address, port and mount point rtsp://YOUR_IP:PORT/MOUNT_POINT. Save and run:

cd ~/ros2_ws/
source install/setup.bash
ros2 launch image2rtsp rtsp.launch.py 

Limitations

• As was previously mentioned, this package allows the conversion of only one topic into an RTSP Stream.
• Some machines may have a significantly bigger delay of about 150-200ms. The reason is currently unknown.
• Its possible to use this package with Humble if ROS2 parameters are hardcoded as variables.

To Do

• Add a branch with the package rewritten as a ROS2 component
• Port the package to Nvidia Jetson Orin. Will the use of the Nvidia encoder make the delay smaller?
• Port packages to ROS2 Humble.
• Complete the functionality according to the functionality of the original ROS package.