Video Streaming issue with OpenCV

Autonomous Machines Jetson & Embedded Systems Jetson Nano
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1

Hi,
Before powering up the Jetson Nano, when I hook up the pi camera, and then after powering the nano and running the OpenCV script, the camera works perfectly fine. But if I unplug the camera while the Jetson is still ON, and if I type ls /dev/video0 , it still shows the device (/dev/video)
But then when I plug in the camera instantly while the Jetson is still in On, and run the same OpenCV script, the image editor does not appear and I get multiple CRITICAL GStreamer messages in the command line as shown in the OpenCV log. And when I terminate and rerun the script again then it throws an error

opencvError
opencvError1074×206 12.3 KB

Any idea why it is happening? It seems when I unplug the camera, it’s still locked by the hardware. But I do use cam.release() at the end of my script to release both software and hardware resource.
Here is cvlog
cvlog.txt (5.7 KB)

Further, I just realized that if I unplug and plug the camera (roughly after 30sec), the script again works!!
Anyway to rlease the CSI handle from the Jetson nano?

3

Hi,
After you remove the camera, please stop nvargus-daemon:

$ sudo service nvargus-daemon stop

And once the camera is re-plugged, please re-start the service:

$ sudo service nvargus-daemon start
4

It still doesn’t work. I just see black image editor.

5

I may be wrong, but I don’t think CSI or camera driver supports hot-plugging. Did you find any reference it should ?
It may work in some cases, but not sure the driver will properly handle any possible case.

I don’t think this is opencv related. You may just use nvgstcapture for checking.

6

Well, the hot-plugging certainly works for pi camera v2 but fails for other cameras so I thought if there was a way to release the CSI lock. But I guess you are right, it depends on how the hardware handles each camera pipeline.