Release webcamera stream

[leonidwang]

WebcamVideoStream initialized stream from cv2.VideoCapture but didn't release it in stop().

[jrosebr1]

Releasing the cv2.VideoCapture pointer should be performed in your main thread. An example of which can be found here:

https://www.pyimagesearch.com/2018/08/13/opencv-people-counter/

[leonidwang]

Nice example on people counter! :)

However, I still think WebcamVideoStream shall release camera.
People call vs.start() / vs.stop() as a pair, it's unusual to ask people to release camera by manually calling vs.stream.release(), people shouldn't even be aware of vs.stream if it's been wrapped by WebcamVideoStream.

See the snippet below, we shall eliminate manual reference and release of vs.stream, right?

In [1]: from imutils.video import WebcamVideoStream

In [2]: vs = WebcamVideoStream(src=0)
   ...: vs.start()
   ...:
   ...:
Out[2]: <imutils.video.webcamvideostream.WebcamVideoStream at 0x1c42477d470>

In [3]: cap = vs.stream

In [4]: vs.stop()

In [5]: cap.isOpened()
Out[5]: True

In [6]: cap.release()

In [7]: cap.isOpened()
Out[7]: False

[liquiddandruff]

I agree that having vs.stream.release() called automatically from vs.stop() should be the default, expected behavior.

[Abik1111]

Well, this technique worked for me, the previous vs.stop() didn't work!!