I have AV.IO HD and it behaves strangely on Linux/OpenCV. I want to capture frames at a maximum speed, thus it is connected to the USB 3 port of my RPI 4 board. v4l2-ctl shows that at 640x480 it can grab 60 fps and my tests show that it is true.
However, each 3 first frames are green (no real picture of the webcam to which AV.IO is connected) and dmesg log has the error: “uvcvideo: Non-zero status (-71) in video completion handler.” - this dmesg error happens when device is opened. Further frames are good. This issue is not happening if AV.IO is connected to USB 2 port, but FPS is low in that case.
I found similar discussions on the open web, e.g. https://lists.freedesktop.org/archives/libqmi-devel/2014-October/000985.html. It assumes that there is some issue either in hardware or firmware of the UVC device.
Linux: Linux 5.10.52-v7l+ #1440 SMP Tue Jul 27 09:55:21 BST 2021 armv7l GNU/Linux
I appreciate any kind of support. Thanks in advance.