cv2: [ WARN:0] global cap_msmf.cpp (674) SourceReaderCB::~SourceReaderCB terminating async callback [duplicate]

Answer 1

A warning message is not an error!

But if that bothers you so much, you might try to disable MSMF by setting the following Environment Variable to 0 on Windows:

OPENCV_VIDEOIO_PRIORITY_MSMF

How to set the path and environment variables in Windows

Answer 2

I've solved, the problem was that i had open my code executing already, make sure you have closed all your builds

Answer 3

This seems to be a bug in MSMF backend of opencv. You can see more details in this issue.

I don't think this problem exists on Linux platforms. So I am providing the solution for windows.

Windows only solution

For windows platform, you can change the backend to something else (most preferably DirectShow backend. For this, add to your VideoCapture like below:

captureDevice = cv2.VideoCapture(0, cv2.CAP_DSHOW) #captureDevice = camera

This works for OpenCV>=3.4.