camera_async.py

import cv2, queue, threading, time


class VideoCapture:
    def __init__(self, name):
        self.cap = cv2.VideoCapture(name)
        self.q = queue.Queue()
        t = threading.Thread(target=self._reader)
        t.daemon = True
        t.start()

    def _reader(self):
        while True:
            ret, frame = self.cap.read()
            if not ret:
                break
            if not self.q.empty():
                try:
                    self.q.get_nowait()
                except Queue.Empty:
                    pass
            self.q.put(frame)

    def read(self):
        return self.q.get()


def capture_img(cap, tt):
    if tt == 'tt':
        frame = cap.read()
        cv2.imshow("demo", frame)
        

if __name__=='__main__':

    cap = VideoCapture(0)
    while True:
        tt = input('Type something: ')
        capture_img(cap, tt)
        tt = ''

        if chr(cv2.waitKey(1)&255) == 'q':
            break
    # try https://pypi.org/project/acapture/ if you need