Playing a sound (AIFF) file from Python using PySDL2

import sdl2
import sys
import aifc
import threading

class ReadAIFF:
  def __init__(self, fileName):
    self.a = aifc.open(fileName)
    self.frameUpto = 0
    self.bytesPerFrame = self.a.getnchannels() * self.a.getsampwidth()
    self.numFrames = self.a.getnframes()
    self.done = threading.Event()
    
  def playNextChunk(self, unused, buf, bufSize):
    framesInBuffer = bufSize/self.bytesPerFrame
    framesToRead = min(framesInBuffer, self.numFrames-self.frameUpto)

    if self.frameUpto == self.numFrames:
      self.done.set()

    # TODO: is there a faster way to copy the string into the ctypes
    # pointer/array?
    for i, b in enumerate(self.a.readframes(framesToRead)):
      buf[i] = ord(b)

    # Play silence after:
    # TODO: is there a faster way to zero out the array?
    for i in range(self.bytesPerFrame*framesToRead, self.bytesPerFrame*framesInBuffer):
      buf[i] = 0

    self.frameUpto += framesToRead

if sdl2.SDL_Init(sdl2.SDL_INIT_AUDIO) != 0:
  raise RuntimeError('failed to init audio')

p = ReadAIFF(sys.argv[1])
spec = sdl2.SDL_AudioSpec(p.a.getframerate(),
                          sdl2.AUDIO_S16MSB,
                          p.a.getnchannels(),
                          512,
                          sdl2.SDL_AudioCallback(p.playNextChunk))

# TODO: instead of passing None for the 4th arg, I really should pass
# another AudioSpec and then confirm it matched what I asked for:
devID = sdl2.SDL_OpenAudioDevice(None, 0, spec, None, 0)
if devID == 0:
  raise RuntimeError('failed to open audio device')

# Tell audio device to start playing:
sdl2.SDL_PauseAudioDevice(devID, 0)

# Wait until all samples are done playing
p.done.wait()

sdl2.SDL_CloseAudioDevice(devID)