Mutlti Threads Not working

[Tricky]

Newbee question.
I try to screenshot multiple rtsp streams using threads. unfortunately it seems that opencv only handle one stream at the time

ex;

def mutiple_threads() # run x 100 threads
cap = cv2.VideoCapture(stream)
ret, frame = cap.read()
cv2.imwrite(pathtosave, frame)

only one opencv is running and blocking the rest from the threads.
Is there a way to run multiple opencv at the same time using threads ?

also how do i kill a running opencv after a certain time. Can’t find a timeout or similar.

timer + cap.release() no succes.

regards,
Tricky

[cudawarped]

VideoCapture with the FFMpeg backend has a lock in VideoCapture::open() which means that only one open can happen in any thread at any one time. See below for more details

Windows FFMPEG back end VideoCapture::open() blocks VideoCapture::open() and VideoWriter::open() in other threads

With rtsp streams this is more apparent because each stream can take a number of seconds to open. Try with a video file to see if the situation improves.