2 usb cameras error


I’m trying to connect two usb2 cameras to the board (regular uvc protocol MJPEG stream)
and I’m getting the flowing error trying to open both simultaneously :

“VIDIOC_STREAMON: No space left on device”

This does not happen on any SBC we have(RPI3,RPI4,tx2 etc…)
Running on latest Ubuntu server image, vim3 pro.

@rider Can you provide complete log information ? We can’t infer from this message where the problem is.THX

khadas@Khadas:~$ $ python3
Python 3.7.3 (default, Apr  3 2019, 19:16:38)
[GCC 8.0.1 20180414 (experimental) [trunk revision 259383]] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import cv2
>>> cc0 = cv2.VideoCapture('/dev/video0',cv2.CAP_V4L)
>>> cc3 = cv2.VideoCapture('/dev/video3',cv2.CAP_V4L)
>>> cc0.read()
(True, array([[[ 28, 133, 160],
    [ 27, 132, 158],  **(cut to fit msg)  ...** , dtype=uint8))  
>>> cc3.read()
VIDIOC_STREAMON: No space left on device
(False, None)

note - if i release the stream a can read from cc3:

    >>> cc0.release()
    >>> cc3.read()
    (True, array([[[246, 248, 248],
     **(cut to fit msg)  ...** , dtype=uint8))


hi frank,

Did you have a chance to check this?

@rider We had check it last week. But we hadn’t found the reason yet. This will be in our plan, but it may take some time.