How to draw Filled rectangle to every frame of video by using Python-OpenCV?

In this article, we will discuss how to draw a filled rectangle on every frame of video through OpenCV in Python.

Stepwise Implementation:

• Import the required libraries into the working space.
• Read the video on which you have to write.

Syntax:

cap = cv2.VideoCapture(“path”)

• Create an output file using cv2.VideoWriter_fourcc() method. Here you will have options of video formats.

Syntax:

output = cv2.VideoWriter(“output.avi”, cv2.VideoWriter_fourcc(*’MPEG’), 30, (1080, 1920))

• Then edit the frames of the video by adding shapes to it (In our case it is a filled rectangle). We will use the cv2.rectangle() method. This method is used to draw a rectangle on any image.

Syntax:

cv2.rectangle(frame, (100, 100), (500, 500), (0, 255, 0), -1)

• Then write all the frames in the video file.

Syntax:

output.write(frame)

Example:

In this example, we add a green rectangle to the video.

Input Video:

Python3

import cv2


def main():

    # reading the input
    cap = cv2.VideoCapture("input.mp4")

    output = cv2.VideoWriter(
        "output.avi", cv2.VideoWriter_fourcc(*'MPEG'),
      30, (1080, 1920))

    while(True):
        ret, frame = cap.read()
        if(ret):

            # adding filled rectangle on each frame
            cv2.rectangle(frame, (100, 150), (500, 600),
                          (0, 255, 0), -1)

            # writing the new frame in output
            output.write(frame)
            cv2.imshow("output", frame)
            if cv2.waitKey(1) & 0xFF == ord('s'):
                break
        else:
            break

    cv2.destroyAllWindows()
    output.release()
    cap.release()


if __name__ == "__main__":
    main()

Output: