DirectSound examples

Existing document

\com\win32comext\directsound\src\directsound.cpp

Just the commented code at the end of the file.

Example

Our raison d’etre - playing sounds:

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

def wav_header_unpack(data):
   '''Unpack a wav header and stuff it into a WAVEFORMATEX structure'''
   (riff, riffsize, wave, fmt, fmtsize, format, nchannels, samplespersecond,
   datarate, blockalign, bitspersample, data, datalength) \
   = struct.unpack('<4sl4s4slhhllhh4sl', data)

   if riff != 'RIFF' or fmtsize != 16 or fmt != 'fmt ' or data != 'data':
      raise ValueError, 'illegal wav header'

   wfx = pywintypes.WAVEFORMATEX()
   wfx.wFormatTag = format
   wfx.nChannels = nchannels
   wfx.nSamplesPerSec = samplespersecond
   wfx.nAvgBytesPerSec = datarate
   wfx.nBlockAlign = blockalign
   wfx.wBitsPerSample = bitspersample

   return wfx, datalength

# Play a wav file and wait until it's finished
fname = os.path.join(os.path.dirname(__file__), "01-Intro.wav")
f = open(fname, 'rb')

# Read and unpack the wav header
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)

@ex This example shows how to record into a wav file:|

import pywintypes
import struct
import win32event
import win32com.directsound.directsound as ds

def wav_header_pack(wfx, datasize):
   return struct.pack('<4sl4s4slhhllhh4sl', 'RIFF', 36 + datasize,
                     'WAVE', 'fmt ', 16,
                     wfx.wFormatTag, wfx.nChannels, wfx.nSamplesPerSec,
                     wfx.nAvgBytesPerSec, wfx.nBlockAlign,
                     wfx.wBitsPerSample, 'data', datasize);

d = ds.DirectSoundCaptureCreate(None, None)

sdesc = ds.DSCBUFFERDESC()
sdesc.dwBufferBytes = 352800 # 2 seconds
sdesc.lpwfxFormat = pywintypes.WAVEFORMATEX()
sdesc.lpwfxFormat.wFormatTag = pywintypes.WAVE_FORMAT_PCM
sdesc.lpwfxFormat.nChannels = 2
sdesc.lpwfxFormat.nSamplesPerSec = 44100
sdesc.lpwfxFormat.nAvgBytesPerSec = 176400
sdesc.lpwfxFormat.nBlockAlign = 4
sdesc.lpwfxFormat.wBitsPerSample = 16

buffer = d.CreateCaptureBuffer(sdesc)

event = win32event.CreateEvent(None, 0, 0, None)
notify = buffer.QueryInterface(ds.IID_IDirectSoundNotify)

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

buffer.Start(0)

win32event.WaitForSingleObject(event, -1)

# in real life, more, smaller buffers should be retrieved
data = buffer.Update(0, 352800)

f = open('recording.wav', 'wb')
f.write(wav_header_pack(sdesc.lpwfxFormat, 352800))
f.write(data)