Only shows first frame / image then errors out

[gotschi]

I always get this error, Script connects successfully, turns Hue Gradient dark and then shows colors of picture / first frame.

python3 harmonize.py -g 2 -i a.b.c.d -f bigbuckbunny.mp4

Then this shows up:

  File "/usr/lib/python3.9/threading.py", line 954, in _bootstrap_inner
    self.run()
  File "/usr/lib/python3.9/threading.py", line 892, in run
    self._target(*self._args, **self._kwargs)
  File "/HarmonizeProject/harmonize.py", line 378, in cv2input_to_buffer
    rgbframe = cv2.cvtColor(bgrframe, cv2.COLOR_BGR2RGB) #corrects BGR to RGB
cv2.error: OpenCV(4.5.1) ../modules/imgproc/src/color.cpp:182: error: (-215:Assertion failed) !_src.empty() in function 'cvtColor'```