Python - Writing to video with OpenCV

Last Updated : 03 Jan, 2023

In this article, we will discuss how to write to a video using OpenCV in Python.

Approach

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

Syntax:

cap = cv2.VideoCapture("path")

Create a output file using cv2.VideoWriter_fourcc() method

Syntax:

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

Then edit the frames of the video by adding shapes to it (for the example given here, the same can be applied to any other technique.).

Syntax:

cv2.rectangle(frame, (100,100), (500,500), (0,255,0), 3)

Then write the video.

Syntax:

output.write(frame)

Example: Program to write to video

Video Used:

Python

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 rectangle on each frame
            cv2.rectangle(frame, (100, 100), (500, 500), (0, 255, 0), 3)
            
            # writing the new frame in output
            output.write(frame)
            cv2.imshow("output", frame)
            if cv2.waitKey(1) & 0xFF == ord('s'):
                break

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


if __name__ == "__main__":
    main()