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to loop through a video, but I've found that it always errors out on the last frame. I'm currently using this instead

while (cap.get(1) < cap.get(7)):
but is there something I need to do to get the first method to work and not error out?
I'm just doing normal things within the while loop; an example is below:
while (cap.get(1) < cap.get(7)): #(cap.isOpened()):
    ret, frame = cap.read()
    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
    cv2.imshow('frame',gray)
    if cv2.waitKey(1) & 0xFF == ord('q'): 
        break
The first method is most likely failing because you're reading a frame after the video is over (and thus getting a blank frame), and then trying to do things to that blank frame which aren't allowed. You can add a check to see if the frame you got was blank:
    while(cap.isOpened()):
        ret, frame = cap.read()
        if frame is None:
            break
I believe this should fix the issue.
    # reading frames
    success, img = cap.read()
    # success will be true if the images are read successfully.
    if success:
        # Do your work here
    else:
        print("Did not read the frame")
                What does this answer add to the answer that has already been accepted? If there is a valuable addition, please explain it. Otherwise, please delete it.
– Captain Hat
                Dec 9, 2022 at 13:12
        
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