low framerate on image_raw topic

hogx

I am using an OAK FFC 4P with two mono cameras on CAMB/C and running it on the ROS2 humble v2.12.2 driver. I can change the framerate of each camera in my config file, but it only affects the imageraw/compressed topic, the image_raw topic shows 5-10Hz when set to 20Hz and it is very laggy. I have a strong USB connection, thus bandwidth shouldn't effect the issue. Has someone else experienced something similar?

my settings:

/**:

ros__parameters:

camera:

  i_enable_imu: false

  i_enable_ir: false

  i_nn_type: none

  i_pipeline_type: Stereo



left:

  i_fps: 20.0

right:

  i_fps: 20.0

OskarSonc

Hey hogx - this looks less like a USB issue and more like a ROS2 raw-image transport/viewer bottleneck.

On depthai-ros 2.12.2, with i_pipeline_type: Stereo, left.i_fps and right.i_fps are the relevant FPS settings, so if image_raw/compressed follows 20 Hz but image_raw is laggy, the camera is likely fine and the slowdown is happening on the host side.

I would try reducing the queue size for the left/right streams, and also verify the rate with something other than just RViz or ros2 topic hz, since raw image topics are easy to under-report or fall behind on.

Also, if you actually want the stereo-depth pipeline, try i_pipeline_type: Depth instead of Stereo.

I would not expect another 2.x release alone to fix this tho, but if you can test the newer Humble V3 driver (depthai_ros_driver_v3 / v3_humble), that is the newer recommended stack and is worth trying.

Thanks,
Oskar