python - Pygame/Tkinter 音乐播放器 : Time slider causes choppy audio

Question

我正在使用 Pygame 和 Tkinter 构建一个音乐播放器，目前正在尝试添加一个工作时间 slider ，允许您通过拖动 slider 跳到歌曲中的特定点。

我将 slider 结尾的值(配置中的“to”)设置为当前歌曲的长度，然后用“after”更新 slider ，如下所示:

def update_timeslider(self, _ = None):
    time = (pygame.mixer.music.get_pos()/1000)
    timeslider.set(time)
    self.after(1000, self.update_timeslider)

这可以随着歌曲的时间移动 slider ，但现在我正在尝试实现提示功能并遇到问题。我尝试使用

将歌曲位置更新为 slider 的值

def cue(self, _ = None):
    pygame.mixer.music.set_pos(timeslider.get()) 

现在当我播放这首歌时，它非常不稳定。当我移动 slider 时，它会在“after”函数更新之前工作一瞬间，但随后会跳回到移动之前的位置。我尝试提高刷新率，但它只会使它更快地跳回并保持不稳定。

有更好的方法吗？

完整代码:

import os
import pygame
import tkinter
from tkinter.filedialog import askdirectory
from tkinter import *
from tkinter import ttk

playlist = [] 
index = 0
paused = False

class Application(tkinter.Tk):
    def __init__(self, parent):
        tkinter.Tk.__init__(self, parent)
        self.minsize(400,400)
        self.parent = parent
        self.main()

    def main(self):
        global v
        global songlabel
        global listbox
        global volumeslider
        global timeslider
        global time_elapsed
        global songlength

        self.configure(background='grey')
        self.grid()
        self.listbox = Listbox(self, width=20, height=25, relief='ridge', bd=3)
        self.listbox.grid(padx=30, pady=15, row=1, columnspan=11, sticky='NSEW')

        v = StringVar()
        songlabel = tkinter.Label(self, textvariable=v, width=30, anchor="n")

        rewbtn = PhotoImage(file="rew.gif")
        stopbtn = PhotoImage(file="stop.gif")
        playbtn = PhotoImage(file="play.gif")
        pausebtn = PhotoImage(file="pause.gif")
        ffbtn = PhotoImage(file="ff.gif")

        prevbutton = Button(self, width=30, height=30, image=rewbtn, anchor='w')
        prevbutton.image = rewbtn
        prevbutton.bind("<Button-1>", self.prevsong)
        prevbutton.grid(row=10, column=0, padx=(30,0), sticky='w')

        playbutton = Button(self, width=30, height=30, image=playbtn, anchor='w')
        playbutton.image = playbtn
        playbutton.bind("<Button-1>", self.play)
        playbutton.grid(row=10, column=1, sticky='w')

        pausebutton = Button(self, width=30, height=30, image=pausebtn, anchor='w')
        pausebutton.image = pausebtn
        pausebutton.bind("<Button-1>", self.pause)
        pausebutton.grid(row=10, column=2, sticky='w')

        stopbutton = Button(self, width=30, height=30, image=stopbtn, anchor='w') 
        stopbutton.image = stopbtn
        stopbutton.bind("<Button-1>", self.stop)
        stopbutton.grid(row=10, column=3, sticky='w')

        nextbutton = Button(self, width=30, height=30, image=ffbtn, anchor='w')
        nextbutton.image = ffbtn
        nextbutton.bind("<Button-1>", self.nextsong)
        nextbutton.grid(row=10, column=4, sticky='w')

        volumeslider = Scale(self, from_=0, to = 1, resolution = 0.01, orient = HORIZONTAL, showvalue = 'yes', command = self.change_vol)
        volumeslider.grid(row=10, column=8, columnspan=3, padx=30, pady=(0,10), sticky='wse')
        volumeslider.set(50)

        timeslider = Scale(self, from_=0, to=100, resolution=1, orient=HORIZONTAL, showvalue = 'no', command=self.cue) 
        timeslider.grid(row=12, column=0, columnspan=11, padx = 30, sticky='wse')
        timeslider.set(0)

        time_elapsed = Label(text="0:00:00")
        time_elapsed.grid(row=13, columnspan=11, padx=(30,0), pady=(0,30), sticky='ws')
        # time_remaining = Label(text="0:00:00")
        # time_remaining.grid(row=13, column = 7, columnspan=5, padx=(0,30), pady=(0,30), sticky='se')

    # FILE OPEN
        self.directorychooser()
        playlist.reverse()
        for items in playlist:
            self.listbox.insert(0, items)
        playlist.reverse()
        self.listbox.bind("<Double-Button-1>", self.selectsong)
        self.listbox.bind("<Return>", self.selectsong)
        songlabel.grid(row = 0, column = 0, columnspan = 10, padx = 55, pady=(10,0), sticky=W+N+E)

    # GRID WEIGHT
        self.grid_columnconfigure(5,weight=1)
        self.grid_columnconfigure(7,weight=1)
        self.grid_rowconfigure(1,weight=1)


    def prevsong(self, event):
        global index

        if index > 0:
            index-=1
            print(index)
        elif index == 0:
            index = len(playlist)-1

        pygame.mixer.music.load(playlist[index])
        self.set_timescale()
        pygame.mixer.music.play()
        self.get_time_elapsed()
        self.update_timeslider()
        self.update_currentsong()


    def play(self, event):
        self.set_timescale()        
        pygame.mixer.music.play()
        self.get_time_elapsed()
        self.update_timeslider()
        self.update_currentsong()


    def pause(self, event): 
        global paused
        if paused == True:
            pygame.mixer.music.unpause()
            paused = False
        elif paused == False:
            pygame.mixer.music.pause()
            paused = True


    def nextsong(self, event):
        global index

        if index < len(playlist)-1:
            index+=1
        elif index == (len(playlist)-1):
            index = 0
        pygame.mixer.music.load(playlist[index])
        self.set_timescale()
        pygame.mixer.music.play()
        self.get_time_elapsed()
        self.update_timeslider()
        self.update_currentsong()


    def stop(self, event):
        pygame.mixer.music.stop()
        v.set("")
        return songlabel


    def selectsong(self, event):
        global index
        global songtime
        global songlength

        idx = self.listbox.curselection()
        index = idx[0]
        pygame.mixer.music.load(playlist[index])

        self.set_timescale()
        pygame.mixer.music.play()
        self.get_time_elapsed()
        # self.get_time_remaining()
        self.update_timeslider()
        self.update_currentsong()


    def change_vol(self, _ = None):
        pygame.mixer.music.set_volume(volumeslider.get())


    def cue(self, _ = None):
        pygame.mixer.music.set_pos(timeslider.get())


    def getsonglen(self):
        s = pygame.mixer.Sound(playlist[index])
        songlength = s.get_length()
        return songlength


    def set_timescale(self):
        songlength = self.getsonglen()
        timeslider.config(to=songlength)    


    def get_time_elapsed(self):
        global time_elapsed
        time = int(pygame.mixer.music.get_pos()/1000)
        m, s = divmod(time, 60)
        h, m = divmod(m, 60)
        clock = "%d:%02d:%02d" % (h, m, s)
        time_elapsed.configure(text=clock)
        self.after(100, self.get_time_elapsed)

    # def get_time_remaining(self):
    #   global time_remaining
    #   time = int(pygame.mixer.music.get_pos()/1000)
    #   songlen = int(self.getsonglen())
    #   rem = songlen - time
    #   m, s = divmod(rem, 60)
    #   h, m = divmod(m, 60)
    #   clock2 = "%d:%02d:%02d" % (h, m, s)
    #   time_remaining.configure(text=clock2)
    #   self.after(100, self.get_time_remaining)


    def update_timeslider(self, _ = None):
        time = (pygame.mixer.music.get_pos()/1000)
        timeslider.set(time)
        self.after(10, self.update_timeslider)


    def update_currentsong(self):
        global index
        global songlabel
        v.set(playlist[index])
        return songlabel


    def directorychooser(self):
        directory = askdirectory()
        os.chdir(directory)
        for files in os.listdir(directory):
            if files.endswith(".flac"):
                realdir = os.path.realpath(files)
                playlist.append(files)
                print(files)
        pygame.mixer.init()
        pygame.mixer.music.load(playlist[0])
        self.update_currentsong()

app = Application(None)
app.mainloop()

Answer 1

问题似乎是 update_timeslider 被调用的次数比您想象的要多。

当你这样做时:

self.update_timeslider()

... 它导致每秒调用 100 次 self.update_timeslider。

问题是您从代码中的多个位置调用它，这意味着您最终可能每秒调用该函数 500-1000 次甚至更多次。如果每次调用都花费很大部分时间，那么您最终会花费比播放声音更多的 CPU 时间来更新 slider 。

当您调用 after 时，它将返回一个 id。您可以使用此 ID 稍后在开始新循环之前取消任何现有调用。例如，您可能想做这样的事情:

class Application(tkinter.Tk):
    def __init__(self, parent):
        ...
        self.after_id = None

    def update_timeslider(self, _ = None):
        if self.after_id is not None:
            self.after_cancel(self.after_id)
            self.after_id = None

        time = (pygame.mixer.music.get_pos()/1000)
        timeslider.set(time)
        self.after_id = self.after(1000, self.update_timeslider)