[Unitree Go2] Trouble subscribing to Unitree Go2 camera topic

Software
1

Hi everyone,

I’m working with a Unitree Go2 EDU robot and trying to integrate its data streams into a FastAPI + ROS2 bridge for a custom dashboard. I’ve run into an issue with the camera feed topic.

  • The topic /frontvideostream is visible with ros2 topic list.
  • When I run ros2 topic info /frontvideostream, it shows the type as unitree_go/msg/Go2FrontVideoData (sometimes mixed with sensor_msgs/msg/CompressedImage or sensor_msgs/msg/Image).
  • If I try to ros2 topic echo /frontvideostream or subscribe to it as CompressedImage, I get CycloneDDS errors like:
[rmw_cyclonedds_cpp] serdata.cpp: invalid data size
[rmw_cyclonedds_cpp] serdata.cpp: unable initialize generic sequence
  • Basically the subscriber crashes because the type doesn’t match.

Has anyone successfully integrated the Go2 camera into their own visualization/dashboard pipeline, and how did you handle the custom message?
Any guidance would be much appreciated :pray:
Thanks in advance!

2

Hi the unitree topic is coming as a special unitree msg and not a ros2 video stream. You can refer to unitree docs for the exact topic interface type or simply ros2 topic info /frontvideostream -v

3

Is there a working example of using /frontvideostream in ROS 2 (or any other way apart from the sdk) ?
I’m trying to get it running, but I’m not sure how to interpret the data inside the Go2FrontVideoData message, especially the video720p array:

The frontvideostream type is unitree_go/msg/Go2FrontVideoData

uint64 time_frame
uint8[] video720p
uint8[] video360p
uint8[] video180p

I tried concatenating video720p packets directly into a file and playing it with ffplay. The result is only partially correct: I can see some content, but only the top rows of the image render properly (see screenshot).

image
image1488×929 51.8 KB

and the code i got the file with :

#include <rclcpp/rclcpp.hpp>
#include <unitree_go/msg/go2_front_video_data.hpp>
#include <fstream>

class Go2VideoDumpRaw : public rclcpp::Node {
public:
  Go2VideoDumpRaw()
  : Node("go2_video_dump_raw"),
    f720_("stream.h264", std::ios::binary | std::ios::trunc)
  {
    std::string topic = declare_parameter<std::string>("topic", "frontvideostream");

    if (!f720_) {
      RCLCPP_FATAL(get_logger(), "Failed to open one or more output files");
      throw std::runtime_error("cannot open output files");
    }

    sub_ = create_subscription<unitree_go::msg::Go2FrontVideoData>(
      topic, rclcpp::SensorDataQoS(),
      std::bind(&Go2VideoDumpRaw::cb, this, std::placeholders::_1));

    RCLCPP_INFO(get_logger(), "Dumping raw packets from '%s' to stream.h264",
                topic.c_str());
  }

private:
  void cb(const unitree_go::msg::Go2FrontVideoData::SharedPtr msg) {
    if (!msg) return;

    if (!msg->video720p.empty()) {
      f720_.write(reinterpret_cast<const char*>(msg->video720p.data()),
                  static_cast<std::streamsize>(msg->video720p.size()));
      f720_.flush();
    }
  }

  rclcpp::Subscription<unitree_go::msg::Go2FrontVideoData>::SharedPtr sub_;
  std::ofstream f720_;
};

int main(int argc, char** argv) {
  rclcpp::init(argc, argv);
  rclcpp::spin(std::make_shared<Go2VideoDumpRaw>());
  rclcpp::shutdown();
  return 0;
}

Any advice would be greatly appreciated, since there isn’t much documentation available online about /frontvideostream :pray:

4

You can refer to the qre_go2 repositories go2_platform ros2 packages → video stream script to see how it works as it sends the stream as compressed sensor image_raw and image_raw

If you do not have access to the qre_go2 or havent purchased the robot from us then you can refer to unitree_sdk2’s src script which has an example of streaming and decoding it.

5

First of all, thank you for your response. I have a follow-up question: where can I find the actual implementation of the decoding process? I only see the header files here: video_client.hpp

It looks like the SDK doesn’t include the source code, but instead provides only the precompiled libraries under the lib folder) it seems to come without source in the sdk as ther is a lib folder

6

Here is the link to the example