将多个视频中的帧提取到多个文件夹中

我想每3秒钟从3个视频（即001_134.flv，028_233.flv和033_993.flv）中提取帧，并将这些相应的帧保存到其特定的文件夹（文件夹名称是视频名称，即001_134， 028_233和033_993）。我怎样才能做到这一点？

目前，我只能提取一部视频的帧，这是一部视频的代码：

import cv2
import os
import logging


def read_video(input_filename):
    return cv2.VideoCapture(input_filename)


def save_frame(count, sec, vid_cap, output_directory):
    vid_cap.set(cv2.CAP_PROP_POS_MSEC, sec * 1000)
    hasFrames, frame = vid_cap.read()

    if hasFrames:
        name = os.path.join(os.getcwd(), output_directory, "frame" + str(count) + ".png")
        cv2.imwrite(name, frame)

    return hasFrames


def get_frames(input_filename, output_directory, frameRate):
    """
    Capture images from a video at every (i.e, 5 sec, 5 mn, etc.)
    :param frameRate: the time we want to capture the images, in seconds.
    """
    try:
        if not os.path.exists(output_directory):
            os.makedirs(output_directory)
    except OSError:
        logging.error('Error creating directory')

    sec = 0
    count = 1
    vid_cap = read_video(input_filename)
    success = save_frame(count, sec, vid_cap, output_directory)

    while success:
        count += 1
        sec = sec + frameRate
        sec = round(sec, 2)
        success = save_frame(count, sec, vid_cap, output_directory)


if __name__ == "__main__":
    input_filename = 'videos/01_123.flv'
    output_directory = 'frames'
    seconds = 30

    get_frames(input_filename, output_directory, seconds)