C / C++ / MFC

// Check that we actually have an Audio input device<br />
uiNumWaveInDevices = waveInGetNumDevs();<br />
<br />
waveInGetDevCaps(0, &WaveInCaps, sizeof(WaveInCaps));  // I always use device 0<br />
<br />
// Check that the audio device supports 16-bit mono 11.025 kHz<br />
if (!(WaveInCaps.dwFormats & WAVE_FORMAT_1M16))<br />
	// Abort audio capture<br />
<br />
// Hard-code the wave format!<br />
AudioFormat.wFormatTag = WAVE_FORMAT_PCM;<br />
AudioFormat.nChannels = 1; // Mono<br />
AudioFormat.nSamplesPerSec = 11025; // 11.025 kHz<br />
AudioFormat.nBlockAlign = 2; // 2 bytes per sample<br />
AudioFormat.wBitsPerSample = 16; // 16 bits per sample<br />
AudioFormat.nAvgBytesPerSec = 11025 * 2; // obvious<br />
AudioFormat.cbSize = 0; // no additional data<br />
<br />
hAudioInDevice = NULL;<br />
<br />
// Open wave in device number 0<br />
uiReturn = waveInOpen(&hAudioInDevice, 0, &AudioFormat, 0, 0, CALLBACK_NULL);<br />
if (uiReturn != MMSYSERR_NOERROR)<br />
	// Abort audio capture<br />
<br />
uiAudioBufferMaxSize = AudioFormat.nSamplesPerSec * 	AudioFormat.nBlockAlign * AudioFormat.nChannels / 25;<br />
// 25 = number video & audio frames per second for PAL<br />
<br />
AudioHeader[uiCounter].lpData = GlobalLock(GlobalAlloc(GMEM_FIXED, uiAudioBufferMaxSize));<br />
<br />
for(uiCounter = 1; uiCounter<uiMaxNumOfFrames; uiCounter++)<br />
	pAudioDataBlock[uiCounter] = pAudioDataBlock[0] + uiCounter * uiAudioBufferMaxSize;<br />
<br />
// Prepare the buffers<br />
uiAudioBufferActualSize = uiAudioBufferMaxSize;<br />
for(uiCounter = 0; uiCounter<DEF_NumberAudioDeviceBuffers; uiCounter++)<br />
{<br />
	AudioHeader[uiCounter].dwBufferLength = uiAudioBufferActualSize;<br />
	AudioHeader[uiCounter].dwBytesRecorded = 0;<br />
	AudioHeader[uiCounter].dwUser = 0;<br />
	AudioHeader[uiCounter].dwFlags = 0;<br />
	AudioHeader[uiCounter].dwLoops = 0;<br />
	uiResult = waveInPrepareHeader(hAudioInDevice, &(AudioHeader[uiCounter]), sizeof(WAVEHDR));<br />
}<br />
<br />
// Start capture - initially queue about 5 audio buffers, to keep the audio capture busy if the<br />
// processor is busy on other stuff - I think this is handled by the audio hardware.<br />
<br />
// Queue the corresponding audio buffer<br />
for (i = 1 to 5)<br />
	waveInAddBuffer(hAudioInDevice, &(AudioHeader[uiNextIndexToQueue]), sizeof(WAVEHDR))<br />
<br />
// If this is the first audio buffer, start the waveIn device<br />
if (bThisIsFirstBuffer)<br />
	waveInStart(hAudioInDevice);<br />
<br />
// Now, in the main capture loop, wait for audio (and video) buffers to be ready<br />
<br />
while (!(AudioHeader[uiAudioNextIndexToProcess].dwFlags & WHDR_DONE))<br />
	;<br />
<br />
// Copy the completed device audio block to our program audio data storage area<br />
// The block which is ready to be saved is in<br />
// AudioHeader[uiAudioNextIndexToProcess]<br />
// and we need to copy uiAudioBufferActualSize bytes<br />
// to the memory pointed to by <br />
// pAudioDataBlock[uiNextIndexToProcess]<br />
<br />
memcpy(pAudioDataBlock[uiNextIndexToProcess], AudioHeader[uiAudioNextIndexToProcess].lpData, uiAudioBufferActualSize);<br />
 // You can process this with your algorithm<br />
<br />
// Queue the next audio buffer<br />
waveInAddBuffer(hAudioInDevice, &(AudioHeader[uiAudioNextIndexToQueue]), sizeof(WAVEHDR))<br />
// Don't queue any more if you are stopping capture, of course!<br />
<br />
//End of main capture loop<br />
<br />
// And when you have finished capturing, stop capture device<br />
waveInStop(hAudioInDevice);<br />
<br />
// Once all capture is finished (i.e. when closing the program), do clean-up<br />
// First UnPrepare the audio buffers<br />
for(uiCounter = 0; uiCounter<DEF_NumberAudioDeviceBuffers; uiCounter++)<br />
{<br />
	while (!(AudioHeader[uiCounter ].dwFlags & WHDR_DONE))<br />
		;<br />
	waveInUnprepareHeader(hAudioInDevice, &(AudioHeader[uiCounter]), sizeof(WAVEHDR)))<br />
	GlobalFree(GlobalHandle(AudioHeader[uiCounter].lpData));<br />
}<br />
<br />
GlobalFree(GlobalHandle(pAudioDataBlock[0]));<br />
<br />
GlobalFree(GlobalHandle(pAudioDataBlock));<br />
<br />
waveInClose(hAudioInDevice);

xianwuluo wrote:

if use PostMessage() to pass pointer and length, then the buffer could be overwriten by HighPriorityThread() before LowPriorityThread read the buffer.

CreateMutex(...)<br />
OpenMutex(...)<br />
ReleaseMutex(...)

suezzz00 wrote:

I suspect that the event that is created is not an OS event , but rather local to the running application.

HANDLE h = CreateEvent(NULL, FALSE, FALSE, "TestEvent");
WaitForSingleObject(h, 5000);
cout << "past event";

[DllImport("kernel32.dll")]
static extern bool SetEvent(IntPtr hEvent);

[DllImport("Kernel32.dll", SetLastError=true)]
static extern IntPtr OpenEvent(uint dwDesiredAccess, bool bInheritHandle, string lpName);

IntPtr handle = OpenEvent(0x000F0000 | 0x00100000 | 0x3, false, "TestEvent"); // First parameter is EVENT_ALL_ACCESS
SetEvent(handle);