reader.py

import queue
import threading

import cv2


class VideoCapture:

    def __init__(self, name):
        self.fourcc = cv2.VideoWriter_fourcc(*'XVID')
        self.out = cv2.VideoWriter(
            'output.avi', self.fourcc, 20.0, (640, 480))

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

    # read frames as soon as they are available, keeping only most recent one
    def _reader(self):
        while True:
            ret, frame = self.cap.read()
            if not ret:
                break
            if not self.q.empty():
                try:
                    self.q.get_nowait()  # discard previous (unprocessed) frame
                except queue.Empty:
                    pass
            self.out.write(frame)
            self.q.put(frame)

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