简述Python如何调用系统底层API播放wav文件

# Our raison d'etre - playing sounds

import pywintypes

import struct

import win32event

import win32com.directsound.directsound as ds

import os

WAV_HEADER_SIZE = struct.calcsize('<4sl4s4slhhllhh4sl')

def wav_header_unpack(data):

  '''解包wav文件头信息'''

  (riff, riffsize, wave, fmt, fmtsize, format, nchannels, samplespersecond, \

  datarate, blockalign, bitspersample, data, datalength) = struct.unpack('<4sl4s4slhhllhh4sl', data)

  if riff != b'RIFF' or fmtsize != 16 or fmt != b'fmt ' or data != b'data':

    raise ValueError

  wfx = pywintypes.WAVEFORMATEX()

  wfx.wFormatTag = format

  wfx.nChannels = nchannels

  wfx.nSamplesPerSec = samplespersecond

  wfx.nAvgBytesPerSec = datarate

  wfx.nBlockAlign = blockalign

  wfx.wBitsPerSample = bitspersample

  return wfx, datalength

# 播放wav文件，直到结束

sound_file = "音效-足球观众的欢呼声.wav"

fname = os.path.join(os.path.dirname(__file__), sound_file)

f = open(fname, 'rb')

# 读取/解包wav文件头

hdr = f.read(WAV_HEADER_SIZE)

wfx, size = wav_header_unpack(hdr)

d = ds.DirectSoundCreate(None, None)

d.SetCooperativeLevel(None, ds.DSSCL_PRIORITY)

sdesc = ds.DSBUFFERDESC()

sdesc.dwFlags = ds.DSBCAPS_STICKYFOCUS | ds.DSBCAPS_CTRLPOSITIONNOTIFY

sdesc.dwBufferBytes = size

sdesc.lpwfxFormat = wfx

buffer = d.CreateSoundBuffer(sdesc, None)

event = win32event.CreateEvent(None, 0, 0, None)

notify = buffer.QueryInterface(ds.IID_IDirectSoundNotify)

notify.SetNotificationPositions((ds.DSBPN_OFFSETSTOP, event))

buffer.Update(0, f.read(size))

buffer.Play(0)

win32event.WaitForSingleObject(event, -1)