OpenCV runs out of memory when reading video file

Question

This example of reading video from file with cv2.VideoCapture in python OpenCV runs out of memory:

import cv2
cap = cv2.VideoCapture('file.mp4')
while True:
    ret, frame = cap.read()

It takes ~300 frames at 1920x1080 before it runs out. Tested in both OpenCV 3.0.0 beta and 2.4.8, running in latest Pythonxy on Windows 7 64-bit.

What needs to be added to this code to make it not run out of memory but rather free each frame before reading the next frame?

Answer 1

You can use scikit-image which has a video loader and supports Opencv and Gstreamer backends as per documentation. I have never used Gstreamer.

import cv2
from skimage.io import Video

cap = Video(videofile)
fc = cap.frame_count()
for i in np.arange(fc):
   z = cap.get_index_frame(i)

Now use the frame z for whatever you want to do!

Answer 2

Try

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

to make sure the frame is valid to avoid reading frames forever even not valid.