Read a video in opencv (python)

Question

I'm trying to read a video file in opencv (python 2.7), and I just copied the example in the opencv tutorial, but nothing happens:

import numpy as np
import cv2

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

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

   gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

   cv2.imshow('frame',gray)
   if cv2.waitKey(1) & 0xFF == ord('q'):
     break

cap.release()
cv2.destroyAllWindows()

The function cap.isOpened always returns FALSE.I have already tried to use absolute path in the argument of VideoCapture, but I still get the same result. What am I getting wrong?

Answer 1

Maybe your OpenCV version is not properly installed. You can check your build infos with print cv2.getBuildInformation() if there is any weird components.

I would suggest to rebuild it, or install it via Anaconda to be sure not to miss any package.

Answer 2

您需要定义视频位置或将视频安装到python安装位置

Answer 3

Keep the full path of the video file. For example :-

cap = cv2.VideoCapture("D:\\Video Folder\\input.mp4")

I believe this would solve this issue.