Python OpenCV Opening Vid File vs. Opening Webcam -

i cant figure out why not working.

the following code works using webcam:

import numpy np import cv2 cap = cv2.videocapture(0) # define codec , create videowriter object fourcc = cv2.videowriter_fourcc(*'xvid') out = cv2.videowriter('output.avi',fourcc, 20.0, (640,480)) while(cap.isopened()):     ret, frame = cap.read()     if ret==true:         frame = cv2.flip(frame,0)         # write flipped frame         out.write(frame)         cv2.imshow('frame',frame)         if cv2.waitkey(1) & 0xff == ord('q'):             break     else:         break # release if job finished cap.release() out.release() cv2.destroyallwindows() 

yet when exchange webcam video file, output not generate video. 5.7kb file named output.avi:

import numpy np import cv2 cap = cv2.videocapture('input.avi') # define codec , create videowriter object fourcc = cv2.videowriter_fourcc(*'xvid') out = cv2.videowriter('output.avi',fourcc, 20.0, (640,480)) while(cap.isopened()):     ret, frame = cap.read()     if ret==true:         frame = cv2.flip(frame,0)         # write flipped frame         out.write(frame)         cv2.imshow('frame',frame)         if cv2.waitkey(1) & 0xff == ord('q'):             break     else:         break # release if job finished cap.release() out.release() cv2.destroyallwindows() 

i can see in windows video being processed not being saved. have tried changing resolution match initial video file.

i'm using opencv on ubuntu, , worked me:

out = cv2.videowriter("output.avi", cv.cv_fourcc(*'divx'), fps, (640, 480)) 

see if works on windows.