How to export video as .mp4 using openCV?

Question

I am trying to export video as .mp4 with openCV. I have tried several codecs but for now I had no success.

This is a function that constructs a video from frames:

def create_movie(self, out_directory, fps, total_frames):
    img1 = cv2.imread("temp/scr0.png")
    height, width, layers =  img1.shape
    codec = cv2.cv.CV_FOURCC('X','V','I','D')
    video = cv2.VideoWriter(out_directory, codec, fps, (width, height))

    for i in range(total_frames):
        img_name = "temp/scr" + str(i) + ".png"
        img = cv2.imread(img_name)
        video.write(img)

    video.release()
    cv2.destroyAllWindows()

I usually get next error message, using different codecs:

Tag XVID/0x44495658 incompatible with output codec id '13'

Is is possible to do this and how?

Answer 1

There is a non-direct solution. You export as .avi and then convert to .mp4 using python's call which calls terminal command.

from subprocess import call

dir = out_directory.strip(".avi")
command = "avconv -i %s.avi -c:v libx264 -c:a copy %s.mp4" % (dir, dir)
call(command.split())

Answer 2

May be a little bit late to answer this, but if you want to write an .MP4 file with OpenCV try this:

import cv2
#your previous code here

fourcc = cv2.VideoWriter_fourcc(*'a\0\0\0')
out = cv2.VideoWriter('out.mp4', fourcc, fps, res)

#the character '\0' is the Null-Terminator or simply 0x00 in the ASCII-Table
#tag: *'a\0\0\0' corresponds to 0x00000061

#your following code here