app.py

#!/usr/bin/env python3
import numpy as np
from vcamera import VCamera


class MyVCamera(VCamera):
    """
    Slow motion
    """

    FRAMES = 10
    LAMBDA = 0.2

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

        self.prev_frame = None

    def transform(self, bgr_frame):
        if self.prev_frame is None:
            self.prev_frame = bgr_frame

        frame = (
            MyVCamera.LAMBDA * bgr_frame + (1.0 - MyVCamera.LAMBDA) * self.prev_frame
        )
        self.prev_frame = frame

        return frame.astype(np.uint8)


class MementoCamera(VCamera):
    FRAMES = 100

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

        self.new_memory = []
        self.current_memory = []

    def transform(self, bgr_frame):
        self.new_memory.append(bgr_frame)

        if len(self.new_memory) == MementoCamera.FRAMES:
            self.current_memory = self.new_memory
            self.new_memory = []

        if len(self.current_memory) == 0:
            return bgr_frame
        else:
            return self.current_memory[-1 - len(self.new_memory)]


if __name__ == "__main__":
    vcam = MementoCamera(flip=True)
    vcam.start()
    vcam.join()