Issue with displaying live stream video using cv2.imshow (error :-215)

1

Hello,

I am currently working on a project where I am using OpenCV to capture frames from a video stream and display them using cv2.imshow. However, I am encountering an issue, and I would appreciate your assistance in resolving it.

The error message I’m facing is:

“(-215:assertion failed) size.width>0 && size.height>0 in function ‘cv::imshow’”

I have included the relevant code snippet below:

import cv2

print(cv2.__version__)

# Open the video capture device (0 represents the default camera)
cap = cv2.VideoCapture(r"http://6*.2**.**1.**8/nphMotionJpeg?Resolution=320x240&Quality=Standard")

# Check if the camera opened successfully
try:
    if not cap.isOpened():
        raise Exception("Error: Could not open camera.")
except Exception as e:
    print(e)

# Set color options (you can choose between cv2.COLOR_BGR2RGB or cv2.COLOR_BGR2GRAY)
color_option = cv2.COLOR_BGR2RGB  # Example: convert to RGB color space

# Loop to continuously capture and display frames
while True:
    # Read a frame from the camera
    try:
        ret, frame = cap.read()

        # Check if the frame was read successfully
        if not ret:
            raise Exception("Error: Could not read frame.")

        # Check if the frame dimensions are valid
        if frame.shape[0] > 0 and frame.shape[1] > 0:
            # Apply color option if needed
            if color_option:
                frame = cv2.cvtColor(frame, color_option)

            # Display the captured frame
            cv2.imshow("Video Capture", frame)

            # Save the frame as an image file (example: JPEG format)
            # Change the file extension and parameters as needed
            #cv2.imwrite("captured_frame.jpg", frame)

        else:
            raise Exception("Error: Invalid frame dimensions.")

    except Exception as e:
        print(e)
        # If an error occurs, you can choose to continue or break the loop
        continue

    # Break the loop if 'q' key is pressed
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break

# Release the video capture object and close the OpenCV window
cap.release()
cv2.destroyAllWindows()

After 2-3 min screen look like
image

I have implemented checks to ensure that the frame is read successfully and that its dimensions are valid before attempting to display it. Despite this, I am still encountering the assertion error mentioned above.

Any other way to ignore the frame which is unreadable.

Thank you in advance for your time and assistance.

Best regards,
Nipesh J.

2

After the size check you call cvtColor. That might fail and give you an empty frane

3

I agree with you, but I have removed ‘cvtColor’ and only checked the size, yet I still get the same error.

4

this defies logic.

please print frame.shape before every imshow() call. look at the last value before the exception happens.