OpenCV: how to restart a video when it finishes?

Question

I'm playing a video file, but how to play it again when it finishes?

Javier

Answer 1

If you want to restart the video over and over again (aka looping it), you can do it by using an if statement for when the frame count reaches cap.get(cv2.cv.CV_CAP_PROP_FRAME_COUNT) and then resetting the frame count and cap.set(cv2.cv.CV_CAP_PROP_POS_FRAMES, num) to the same value. I'm using OpenCV 2.4.9 with Python 2.7.9 and the below example keeps looping the video for me.

import cv2

cap = cv2.VideoCapture('path/to/video') 
frame_counter = 0
while(True):
    # Capture frame-by-frame
    ret, frame = cap.read()
    frame_counter += 1
    #If the last frame is reached, reset the capture and the frame_counter
    if frame_counter == cap.get(cv2.cv.CV_CAP_PROP_FRAME_COUNT):
        frame_counter = 0 #Or whatever as long as it is the same as next line
        cap.set(cv2.cv.CV_CAP_PROP_POS_FRAMES, 0)
    # Our operations on the frame come here
    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
    # Display the resulting frame
    cv2.imshow('frame',gray)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break
# When everything done, release the capture
cap.release()
cv2.destroyAllWindows()

It also works to recapture the video instead of resetting the frame count:

if frame_counter == cap.get(cv2.cv.CV_CAP_PROP_FRAME_COUNT):
    frame_counter = 0
    cap = cv2.VideoCapture(video_name)