Python OpenCV Writing to Video

Python OpenCV

About Lesson

In this Python OpenCV lesson we are going to learn about Python OpenCV Writing to Video, basically we want to add a circle in our video.

This is the complete source code for this lesson.

import cv2



def main():
    windowname = "Writing To A Video"
    cv2.namedWindow(windowname)


    cap = cv2.VideoCapture('myvidsample.mp4')

    filename = "out.avi"
    codec = cv2.VideoWriter_fourcc('X', 'V', 'I', 'D')
    framerate = 29
    resolution = (640, 480)

    VideoOutPut = cv2.VideoWriter(filename, codec, framerate, resolution)


    if cap.isOpened():
        ret, frame = cap.read()
    else:
        ret = False


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



        cv2.circle(frame, (200,200), 80, (0,255,0), -1)

        VideoOutPut.write(frame)
        cv2.imshow(windowname, frame)


        if cv2.waitKey(1) == 27:
            break

    cv2.destroyAllWindows()
    VideoOutPut.release()
    cap.release()



if __name__ == "__main__":
    main()

import cv2

def main():

windowname = "Writing To A Video"

cv2.namedWindow(windowname)

cap = cv2.VideoCapture('myvidsample.mp4')

filename = "out.avi"

codec = cv2.VideoWriter_fourcc('X', 'V', 'I', 'D')

framerate = 29

resolution = (640, 480)

VideoOutPut = cv2.VideoWriter(filename, codec, framerate, resolution)

if cap.isOpened():

ret, frame = cap.read()

else:

ret = False

while ret:

ret, frame = cap.read()

cv2.circle(frame, (200,200), 80, (0,255,0), -1)

VideoOutPut.write(frame)

cv2.imshow(windowname, frame)

if cv2.waitKey(1) == 27:

break

cv2.destroyAllWindows()

VideoOutPut.release()

cap.release()

if __name__ == "__main__":

main()

This section of code is for creating and reading from input file. If the input is a camera pass 0 instead of the video filename.

 cap = cv2.VideoCapture('myvidsample.mp4')

1	cap = cv2.VideoCapture('myvidsample.mp4')

When we want to write a video in OpenCV we need some more works. We need to create a VideoWriter object. first, we should specify the output file name with its format (eg: output.avi). then, we should specify the FourCC code and the number of frames per second (FPS). Lastly, the frame size should be passed.

    filename = "out.avi"
    codec = cv2.VideoWriter_fourcc('X', 'V', 'I', 'D')
    framerate = 29
    resolution = (640, 480)

    VideoOutPut = cv2.VideoWriter(filename, codec, framerate, resolution)

filename = "out.avi"

codec = cv2.VideoWriter_fourcc('X', 'V', 'I', 'D')

framerate = 29

resolution = (640, 480)

VideoOutPut = cv2.VideoWriter(filename, codec, framerate, resolution)

We want to add a circle in the video, so this code is used for creating a circle.

 cv2.circle(frame, (200,200), 80, (0,255,0), -1)

1	cv2.circle(frame, (200,200), 80, (0,255,0), -1)

Run the code and this is the result.