OpenCV VideoCapture(FILE) don't work WINDOWS

Question

I'm using this script.py:

import cv2,numpy as np

face_cascade = cv2.CascadeClassifier('haarcascade_frontalface_default1.xml')

cap = cv2.VideoCapture('video.flv')
ret,frame = cap.read()
print ret

while (cap.isOpened()):

    ret,frame = cap.read()

    img = frame

    gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
    faces = face_cascade.detectMultiScale(gray, 1.5, 5)
    for (x,y,w,h) in faces:
    cv2.rectangle(img,(x,y),(x+w,y+h),(255,0,0),2)

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

cv2.destroyAllWindows()

I have added ffmpeg to the path with the bat script:

set PATH=%PATH%;C:\opencv\sources\3rdparty\ffmpeg

I have tried to change the file format to .avi, .flv, .mp4 but it still doesn't work.

I don't have any error, but 'ret = False' everytime.

Answer 1

It's hard to tell what exactly is wrong without more informations about error, but you may try following solutions:

• Rebuild OpenCV with ffmpeg. If you are using Mac OSX you only need to use brew install opencv --with-ffpmeg (or similar command - i can't check it right now, but brew options opencv will give the answer. On Windows probably it's not necessary, but you may try.
• If you are using pre-built binaries, download source (latest STABLE version - right now it's 2.4.10, i wouldn't recommend you 3.0.0 beta version) and build it(with ffpmeg). Use builded binaries (you may need to copy all dll files to directory with cv2.pyd (most likely python_version/Lib/ or python_version/Lib/site-packages). Instruction is here , part "Installation by Making Your Own Libraries from the Source Files". Make sure to check following options: WITH_FFMPEG ( WITH_DSHOW might be usefull on windows as well) and 'BUILD_opencv_python' and configure python (it's decribed in tutorial - instead of using setuptools you may prefer to use pip ). After building solution, in opencv_build/lib/[Release/Debug] you should find cv2.lib , cv2.pyd and cv2.ilk files and in opencv_build/bin/[Release/bin] should be opencv_...version.dll files (... - module name, version - version number). Copy all those files (from lib/[Debug/Release]' and from bin/[Debug/Release]`) to folder in which you currently have cv2.pyd.'