2

I am using a common logitech webcam with OpenCV. When I was using my RPI3 I had no trouble, but I wanted to improve my system so I bought a RPI4.

Upon setting up my system with RPI4 using raspian buster I've started getting:

VIDIOC_DQBUF: Resource temporarily unavailable

After I saw this question here I tried:

pi@raspberrypi:~ $ sudo rmmod uvcvideo
pi@raspberrypi:~ $ sudo modprobe uvcvideo nodrop=1 timeout=5000 quirks=0x80

Now my image comes like this:

Half green image

The upper part of the image is ok, it's night time and it is pointing to my backyard, however I don't know how to solve the green part problem.

Any ideas?

  • Your webcam device is in this list in Supported device : Device works state for 046d:0825 Logitech HD Webcam C270, can you put your dmesg or syslog output ? – Ephemeral Jan 9 at 11:41
  • How did you install opencv? – Ephemeral Jan 9 at 11:53
0

I've managed to do it!!!

This is really needed:

pi@raspberrypi:~ $ sudo rmmod uvcvideo
pi@raspberrypi:~ $ sudo modprobe uvcvideo nodrop=1 timeout=5000 quirks=0x80

But also, I had to set my webcam FPS prop to a low value.

0. CV_CAP_PROP_POS_MSEC Current position of the video file in milliseconds.
1. CV_CAP_PROP_POS_FRAMES 0-based index of the frame to be decoded/captured next.
2. CV_CAP_PROP_POS_AVI_RATIO Relative position of the video file
3. CV_CAP_PROP_FRAME_WIDTH Width of the frames in the video stream.
4. CV_CAP_PROP_FRAME_HEIGHT Height of the frames in the video stream.
5. CV_CAP_PROP_FPS Frame rate.
6. CV_CAP_PROP_FOURCC 4-character code of codec.
7. CV_CAP_PROP_FRAME_COUNT Number of frames in the video file.
8. CV_CAP_PROP_FORMAT Format of the Mat objects returned by retrieve() .
9. CV_CAP_PROP_MODE Backend-specific value indicating the current capture mode.
10. CV_CAP_PROP_BRIGHTNESS Brightness of the image (only for cameras).
11. CV_CAP_PROP_CONTRAST Contrast of the image (only for cameras).
12. CV_CAP_PROP_SATURATION Saturation of the image (only for cameras).
13. CV_CAP_PROP_HUE Hue of the image (only for cameras).
14. CV_CAP_PROP_GAIN Gain of the image (only for cameras).
15. CV_CAP_PROP_EXPOSURE Exposure (only for cameras).
16. CV_CAP_PROP_CONVERT_RGB Boolean flags indicating whether images should be converted to RGB.
17. CV_CAP_PROP_WHITE_BALANCE Currently unsupported
18. CV_CAP_PROP_RECTIFICATION Rectification

Before starting to read the cam just do:

cam.set(cv2.CAP_PROP_FPS, 10)

All set! :)

| improve this answer | |
  • Please accept your own answer with a click on the tick on its left side. Only this will finish the question and it will not pop up again year for year. – Ingo Feb 9 at 14:51
  • There's no checkmark to accept the answer, don't know what to do :( – user113246 Feb 11 at 12:40
  • Sorry, haven't seen that you have just made the answer. Please wait 48 hours, then it should be possible to accept an own answer. – Ingo Feb 11 at 13:03
  • It´s been a month already... – user113246 Feb 13 at 12:23
  • Seems you are using two accounts with the same name. Please use the same account you have made the question, the account with 21 reputation. Only the owner of a question can accept answers, of course. – Ingo Feb 13 at 17:59

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.