[FIXED] error: (-215:Assertion failed) !ssize.empty() in function 'resize' shows up when setting a cv2.resize for frame. What should be done?

Issue

I was following a tutorial to build facial recognition software:

small_frame = cv2.resize(frame, (0,0), fx=0.25,fy=0.25),
rgb_small_frame = small_frame[:,:,::-1]

when this error showed up:

cv2.error: OpenCV(4.6.0) /Users/xperience/actions-runner/_work/opencv-python/opencv-python/opencv/modules/imgproc/src/resize.cpp:4052: error: (-215:Assertion failed) !ssize.empty() in function 'resize'

Solution

This problem was few times on Stackoverflow.

When cv2 can't get frame from file or webcam then it doesn't raise error but it returns status False, and frame None and you should check one of these values before you run rest of code

ret, frame = cap.read()

if ret:  # if ret is True:
    small_frame = cv2.resize(frame, (0,0), fx=0.25,fy=0.25)
    # ... rest of code ...

or

ret, frame = cap.read()

if frame is not None:  # it can't be `if frame:` 
    small_frame = cv2.resize(frame, (0,0), fx=0.25,fy=0.25)
    # ... rest of code ...

Answered By - furas