python批量提取视频中的音频

import moviepy.editor as mp
import os
from tkinter import Tk,Button,messagebox
from tkinter.filedialog import askdirectory
from tkinter.ttk import Progressbar

def extract_audio():
    pb['value']=0
    num=0
    video_folder=askdirectory()
    video_paths=os.listdir(video_folder)
    if video_paths:
        for x in video_paths:
            if x.endswith(".mp4"):
                num+=1
        for i in video_paths:
            if i.endswith(".mp4"):
                pb['value']+=int(100/num)
                root.update()
                video_path=video_folder+"/"+i
                video_name=os.path.splitext(i)[0]
                audio_path=video_folder+"/"+video_name
                #视频读取到my_clip
                my_clip=mp.VideoFileClip(video_path)
                my_clip.audio.write_audiofile(f'{audio_path}.mp3')
        messagebox.showinfo("提示","提取完成")
    else:
        messagebox.showinfo("提示","文件夹为空")
    
if __name__=='__main__':
    root=Tk()
    root.resizable(False,False)
    root.title('提取音频')
    sw=root.winfo_screenwidth()
    sh=root.winfo_screenheight()
    ww=230
    wh=90
    x=(sw-ww)/2
    y=(sh-wh)/2
    root.geometry("%dx%d+%d+%d"%(ww,wh,x,y))
    pb=Progressbar(root,length=210)
    pb.grid(row=0,column=0,padx=10,pady=10)
    pb['maximum']=100
    bt=Button(root,text='选择视频所在的文件夹',command=extract_audio)
    bt.grid(row=1,column=0,padx=10,pady=5)
    root.mainloop()