Trouble with YAML example file

[gjf2a]

I am using ROS2 Humble.

I installed the ros2-humble-usb-cam. I'm trying to set it up with a Logitech CV270 webcam.

I first tried using the usb_cam.yml example. It gave me the following error message:

[ERROR] [1687449780.122892676] [rcl]: Failed to parse global arguments
terminate called after throwing an instance of 'rclcpp::exceptions::RCLInvalidROSArgsError'
  what():  failed to initialize rcl: Couldn't parse params file: '--params-file usb_cam.yml'. Error: Cannot have a value before ros__parameters at line 1, at ./src/parse.c:793, at ./src/rcl/arguments.c:406
[ros2run]: Aborted

After some searching online, I modified it as follows (FYI, my webcam is /dev/video1):

usb_cam:
    ros__parameters:

        start_service_name: "start_capture" 
        stop_service_name: "stop_capture"  

        video_device: /dev/video1           
        io_method: mmap                    
        pixel_format: yuyv                 
        color_format: yuv422p              
        create_suspended: false             
        full_ffmpeg_log: false              
        camera_name: head_camera            
        camera_frame_id: head_camera        
        camera_transport_suffix: image_raw 
        camera_info_url: ""                 
        image_width: 640                   
        image_height: 480
        framerate: 30                       

        intrinsic_controls:
            focus_auto: true
            exposure_auto_priority: true
            exposure_auto: 3
            white_balance_temperature_auto: true
            power_line_frequency: 1
            ignore: [
                brightness,
                contrast,
                saturation,
                gain,
                sharpness,
                backlight_compensation,
                white_balance_temperature,
                exposure_absolute,
                pan_absolute,
                tilt_absolute,
                focus_absolute,
                zoom_absolute
            ]                              

That variation yields the following error:

terminate called after throwing an instance of 'rclcpp::exceptions::InvalidParameterTypeException'
  what():  parameter 'framerate' has invalid type: Wrong parameter type, parameter {framerate} is of type {double}, setting it to {integer} is not allowed.
[ros2run]: Aborted

I next changed the framerate parameter to 30.0. That yielded this error:

[INFO] [1687450137.021337933] [usb_cam]: camera_name value: head_camera
[WARN] [1687450137.021771694] [usb_cam]: framerate: 30.000000
[INFO] [1687450137.035924330] [usb_cam]: using default calibration URL
[INFO] [1687450137.036119211] [usb_cam]: camera calibration URL: file:///home/ferrer/.ros/camera_info/head_camera.yaml
[ERROR] [1687450137.036437053] [camera_calibration_parsers]: Unable to open camera calibration file [/home/ferrer/.ros/camera_info/head_camera.yaml]
[WARN] [1687450137.036536514] [usb_cam]: Camera calibration file /home/ferrer/.ros/camera_info/head_camera.yaml not found
[INFO] [1687450137.036704185] [usb_cam]: Starting 'head_camera' (/dev/video1) at 640x480 via mmap (yuyv) at 30 FPS
terminate called after throwing an instance of 'char*'
[ros2run]: Aborted

I am completely at a loss. Any suggestions would be most welcome!

[twdragon]

Did you copy the sample YAML from the ROS1 version? If yes, merging between current ROS1 and ROS2 code is in progress, so you should not use YAML file from ROS1 to set up ROS2 version

[gjf2a]

It looks like that I did indeed mistakenly use the ROS1 version.

So I went back to the usb_cam site and found what I think is the correct params.yaml example.

It still doesn't seem to recognize my camera. Here is my camera information:

sudo v4l2-ctl --list-devices
[sudo] password for ferrer:
Amlogic Video Decoder (platform:meson-vdec):
        /dev/video0

UVC Camera (046d:0825) (usb-xhci-hcd.0.auto-1.2):
        /dev/video1
        /dev/video2
        /dev/media0

But no matter what video device I try (I tried /dev/video1, /dev/video2, and even /dev/video0 just for comparison), I get the following error message:

ferrer@ferrer-aml-s905x-cc:~$ ros2 run usb_cam usb_cam_node_exe --ros-args --params-file params.yaml
[INFO] [1687450766.510501487] [usb_cam]: camera_name value: test_camera
[WARN] [1687450766.510939914] [usb_cam]: framerate: 30.000000
[INFO] [1687450766.525389172] [usb_cam]: camera calibration URL: package://usb_cam/config/camera_info.yaml
[INFO] [1687450766.528417785] [usb_cam]: Starting 'test_camera' (/dev/video1) at 640x480 via mmap (mjpeg2rgb) at 30 FPS
terminate called after throwing an instance of 'char*'
[ros2run]: Aborted

I tried a couple of other pixel formats (rgb8, yuyv) and it is always this same error.

Any suggestions again most welcome. Thanks for the fast reply earlier!

[twdragon]

@gjf2a what about the reading method?

[gjf2a]

@gjf2a what about the reading method?

I have no idea what the reading method is.

[twdragon]

mmap, userptr, read. Refer to your camera's documentation and datasheets

[gjf2a]

mmap, userptr, read. Refer to your camera's documentation and datasheets

Gotcha. I tried all three of those for the io_method field, and I still get the same error message every time. I'm not sure what else to look for on the data sheet.

[ngifary]

Check if you have permission to /dev/video*

[flynneva]

@gjf2a I am going to go ahead and close this issue as inactive / not exactly sure what the issue really is.

Feel free to debug some more and open a new issue outlining exactly whats wrong and we can help you out! 👍🏼

[alfem]

I've got the very same error as @gjf2a, with a Logitech C270 too and using ros2 humble on ubuntu 22.04

I would like to help with diagnostics and solution. I lowered the framerate to 10 fps and got this error:

[INFO] [1715365395.749175594] [usb_cam]: Timer triggering every 100 ms
Select timeout, exiting...
terminate called after throwing an instance of 'char const*'
[ros2run]: Aborted

I can see camera image with vlc, so permissions are ok.