OpenCV Python VideoWriter wrong fps rate for some codecs

Question

I'm trying to read Videos, resize them and write them with a different codec, using OpenCV for Python3. The original frame rate should stay the same.

This works fine if I'm using MJPG as codec, but for other codecs the frame rate of the output is set to 600 fps. (I tried XVID, DIVX, WMV1, WMV2)

Is it possible to write Videos with those codecs with the original frame rate?

import os
import numpy as np
import cv2

codec = 'XVID'
new_size = (256, 256)

for root, dirs, files in os.walk("UCF-101"):
    new_root = root.replace('UCF-101', 'UCF-101_resized_' + codec)
    if not os.path.exists(new_root):
        os.makedirs(new_root)
    for file in files:
        cap = cv2.VideoCapture(root + '/' + file)
        fps = cap.get(cv2.CAP_PROP_FPS)
        fourcc = cv2.VideoWriter_fourcc(*codec)
        out = cv2.VideoWriter(new_root + '/' + file, fourcc, fps, new_size, isColor=True)
        while(cap.isOpened()):
            ret, frame = cap.read()
            if ret == True:
                frame = cv2.resize(src=frame, dst=frame, dsize=new_size)
                out.write(frame)
            else:
                break
        cap.release()
        out.release()
        print('wrote ' + new_root + '/' + file)

Juan Manuel Restrepo Quijano Juan Manuel Restrepo Quijano · Accepted Answer · 2018-07-10T16:15:07

Try changing your file extension to output file name with .mp4, not avi

codec = 'x264'

Replace if ret == True: with if frame is not None:

OpenCV Python VideoWriter wrong fps rate for some codecs

1 Answers