使用Pyglet播放音频文件的子集

Question

How can I use the pyglet API for sound to play subsets of a sound file eg from 1 second in to 3.5seconds of a 6 second sound clip?

I can load a sound file and play it, and can seek to the start of the interval desired, but am wondering how to stop playback at the point indicated?

Answer 1

It doesn't appear that pyglet has support for setting a stop time. Your options are:

1. Poll the current time and stop playback when you've reached your desired endpoint. This may not be precise enough for you.
2. Or, use a sound file library to extract the portion you want into a temporary sound file, then use pyglet to play that sound file in its entirety. Python has built-in support for .wav files (the "wave" module), or you could shell out to a command-line tool like "sox".

Answer 2

This approach seems to work: rather than poll the current time manually to stop playback, use the pyglet clock scheduler to run a stop callback once after a given interval. This is precise enough for my use case ;-)

player = None

def stop_callback(dt):
  if player != None:
    player.stop()

def play_sound_interval(mp3File, start=None, end=None):
  sound = pyglet.resource.media(mp3File)
  global player
  player = pyglet.media.ManagedSoundPlayer()
  player.queue(sound)
  if start != None:
    player.seek(start)
  if end != None and start != None:
    pyglet.clock.schedule_once(stop_callback, end-start)
  elif end != None and start == None:
    pyglet.clock.schedule_once(stop_callback, end)
  player.play()