Python Forum

I have multiple processes running, and in each, I am trying to resize and image using cv2.resize()

However, when I try, it just seems like the processes end there and then. There are no errors - not a single bit of output, it just ends.

Say I have this:

#do some image processing - image is now stored in 'img':
resized = cv2.resize(img, (10,10))
print(resize)

The output will be some resized numpy array which is correct.
However, if I now do this:

#create some processes - each process runs the piece of code below:
#do some image processing - image is now stored in 'img':
resized = cv2.resize(img, (10,10))
print(resize)

There is NO output. It just ends the process at the resize line.

I have tried debugging it with pdb, and I get no info on it - again it just ends.
I also added this at the beginning of the script:

import logging
mpl = multiprocessing.log_to_stderr()
mpl.setLevel(logging.DEBUG)

And then ran it with pdb - this is what I got:

Output:
(Pdb) b 439
Breakpoint 1 at /Users/everyone/Desktop/SubreddimagesV2/get_images_no_gif.py:439
(Pdb) c
END Value missing from arguments!
[LOG]: Creating gif
[INFO/Process-1] child process calling self.run()
[INFO/Process-2] child process calling self.run()
> /Users/everyone/Desktop/SubreddimagesV2/get_images_no_gif.py(439)create_image_gif()
-> resized = cv2.resize(new_img, (new_img.shape[1]//2, new_img.shape[0]//2, new_img.shape[2]))
(Pdb) 
[INFO/Process-1] process shutting down
[DEBUG/Process-1] running all "atexit" finalizers with priority >= 0
[DEBUG/Process-1] running the remaining "atexit" finalizers
Process Process-1:
Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/multiprocessing/process.py", line 258, in _bootstrap
    self.run()
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/multiprocessing/process.py", line 93, in run
    self._target(*self._args, **self._kwargs)
  File "/Users/everyone/Desktop/SubreddimagesV2/get_images_no_gif.py", line 439, in create_image_gif
    resized = cv2.resize(new_img, (new_img.shape[1]//2, new_img.shape[0]//2, new_img.shape[2]))
  File "/Users/everyone/Desktop/SubreddimagesV2/get_images_no_gif.py", line 439, in create_image_gif
    resized = cv2.resize(new_img, (new_img.shape[1]//2, new_img.shape[0]//2, new_img.shape[2]))
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/bdb.py", line 51, in trace_dispatch
    return self.dispatch_line(frame)
  File "/Library/Frameworks/Python.framework/Versions/3.6/lib/python3.6/bdb.py", line 70, in dispatch_line
    if self.quitting: raise BdbQuit
bdb.BdbQuit
[INFO/Process-1] process exiting with exitcode 1

Now, 'exitcode 1' means there was some kind of error - i'm not sure if this is what is causing the problem, or if it is just because it was quit through this line:

if self.quitting: raise BdbQuit

Either way, what is going on here? Why is cv2.resize not working?

Anyone got an idea?

I already have a workaround in my code but I'm still curious as to know what's going on.