更改视频播放速度 Python/Opencv

功能
根据更改原始视频的播放速度并保存更改视频
可指定fps，也可指定播放倍速，两者同时指定时，以fps为主

依赖库
python3，cv2

代码实现
#!/usr/bin/env python
# -*- coding: utf-8 -*-
# @Time : 2021/04/08
# @Author : Devil_Xiao
# Purpose: This script is used to change the video_speed
# You can choose to specify the fps,
# or you can choose to change the multiple of the original playback speed

import cv2
from cv2 import VideoWriter, VideoWriter_fourcc
import argparse

def video_speed(video_root, out_root, fps=None, scale=1):
“””When fps and scale are specified at the same time, fps is the dominant”””
cap = cv2.VideoCapture(video_root)
video_width = int(cap.get(3))
video_height = int(cap.get(4))
fourcc = cv2.VideoWriter_fourcc(‘m’, ‘p’, ‘4’, ‘v’)
if fps:
videoWriter = cv2.VideoWriter(out_root, fourcc, fps, (video_width, video_height))
else:
fps = int(cap.get(cv2.CAP_PROP_FPS) * scale)
videoWriter = cv2.VideoWriter(out_root, fourcc, fps, (video_width, video_height))
flag = cap.isOpened()

while (flag):
flag, frame = cap.read()
videoWriter.write(frame)
videoWriter.release()

if __name__ == ‘__main__’:
parser = argparse.ArgumentParser()
parser.add_argument(‘–video_name’, type=str, default=r’video.mp4′, help=’original video name’)
parser.add_argument(‘–result_name’, type=str, default=r’result.mp4′, help=’result name’)
parser.add_argument(‘–fps’, type=int, default=None, help=’Specify the playback frame rate’)
parser.add_argument(‘–scale’, type=float, default=’0.5′, help=’Change the original video speed’)
opt = parser.parse_args()
print(opt)
video_speed(opt.video_name, opt.result_name, opt.fps, opt.scale)