Ubuntu Version:
Ubuntu 24.04
Desktop Environment (if applicable):
GNOME
Problem Description:
I have a UVC device for streaming video and while it works under windows and macOS, I am experiencing issues with Ubuntu. In particular, while my device works with VLC and guvcview, it does not work under cheese or snapshot. In particular, I am seeing an error in journalctl “Non-zero status (-71) in video completion handler” for both. Cheese has the additional error “gst_value_set_int_range_step: assertion ‘start < end’ failed and Snapshot has “Failed to resubmit video URB (-1)” error. I’m not sure if these extra errors are related. All errors happen consistently whether using the GUI or command line.
Relevant System Information:
I am using a fresh install of Ubuntu 24.04 downloaded from the official download on May 8th. The kernel is 6.11.0-25-generic.
Screenshots or Error Messages:
I don’t have an easy way to get the full logs off of the device right now
What I’ve Tried:
I have tried to isolate what the problem is. This isn’t clear to me but this is my understanding of what is happening behind the scenes: the hardware video interface is handled by V4L2 or libcamera and gstreamer or pipewire can be used to route the data for the application. Using pw-top to see when pipewire is used, I can see pipewire connections made with the libcamera and v4l2 camera sources when cheese and snapshot are opened but not vlc or guvview. Since vlc and guvcview work, this makes me think it is an issue with pipewire and libcamera. With these apps open, I can switch between 2 camera sources which seems to just be the same camera but through libcamera vs v4l2.
I’ve tried to use gst-launch-1.0 to test each of v4l2, pipewire or libcamera. v4l2src and pipewiresrc have no issues streaming from my camera but libcamerasrc complains about buffering. The libcamera test app qcam works though.
Any help on how to diagnose this -71 error code would be of great help. Thanks