OpenGL and OpenCV with python 2.7 - part 002.

I deal today with opencv and I fix some of my errors.

One is this error I got with cv2.VideoCapture . When I try to used with load video and createBackgroundSubtractorMOG2() i got this:

cv2.error: C:\builds\master_PackSlaveAddon-win64-vc12-static\opencv\modules\highgui\src\window.cpp:281: error: (-215) size.width<0 amp="" cv::imshow="" function="" i="" in="" size.height="">

You need also to have opencv_ffmpeg310.dll and opencv_ffmpeg310_64.dll into your windows C:\Windows\System32 , this will help me to play videos.

Now make sure you have the opencv version 3.1.0 because opencv come with some changes over python.

C:\Python27\python

Python 2.7.8 (default, Jun 30 2014, 16:08:48) [MSC v.1500 64 bit (AMD64)] on win32

Type "help", "copyright", "credits" or "license" for more information.

>>>import cv2

>>>print cv2.__version__

3.1.0

You can take some infos from about opencv python module - cv2 with:

>>>cv2.getBuildInformation()

...

>>>cv2.getCPUTickCount()

...

>>>print cv2.getNumberOfCPUs()

...

>>>print cv2.ocl.haveOpenCL()

True

You can also see some error by disable OpenCL:

>>>cv2.ocl.setUseOpenCL(False)

>>>print cv2.ocl.useOpenCL()

False

Now will show you how to use webcam gray and color , and play one video:

webcam color

import numpy as np

import cv2

cap = cv2.VideoCapture(0)

while(True):

ret, frame = cap.read()

cv2.imshow('frame',frame)

if 0xFF & cv2.waitKey(5) == 27:

break

cap.release()

cv2.destroyAllWindows()

webcam gray

import numpy as np

import cv2

cap = cv2.VideoCapture(0)

while(True):

ret, frame = cap.read()

gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)

cv2.imshow('frame',gray)

if 0xFF & cv2.waitKey(5) == 27:

break

cap.release()

cv2.destroyAllWindows()

play video

import cv2

from cv2 import *

capture = cv2.VideoCapture("avi_test_001.avi")

while True:

ret, img = capture.read()

cv2.imshow('some', img)

if 0xFF & cv2.waitKey(5) == 27:

break

cv2.destroyAllWindows()