Function: Convert the format of a video

[HeZhang1994]

This repository does not provide the code for converting video formats. You can modify the code as below:

command = "ffmpeg -i input_video.mkv -c copy input_video.mp4"

该项目没有提供视频格式转换的代码，如果需要转换视频格式，可以用如下的程序命令：

command = "ffmpeg -i input_video.mkv -c copy input_video.mp4"