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From: sid on 20 Apr 2006 06:53
Hi Guys

Apologies for such a lengthy mail but I want to be elaborate so that
things are clear to the reader...

I am trying to record microphone input into a buffer which I can later
manipulate accordingly or even record on a wave file if need be, but I
am facing nightmares. Can anyone help me out so that I can get going...

At present i have a START and STOP button and the code is as follows in
both click events..(Just to remind its running on a PPC 2003)

Problem: The code hangs after starting the recording and never stops it
and goes in a deadlock situation. I am using a callback routine to
handle messages

HWAVEIN hWaveIn;
WAVEFORMATEX wfex;
WAVEHDR wvhdr;
LPSTR p_Buff;
BOOL fRecording;
MMRESULT mRes;


START
=====

UINT numDevices=waveInGetNumDevs();

/* Initialize the WAVEFORMATEX and WAVEHDR*/

wfex.wFormatTag=WAVE_FORMAT_PCM;
wfex.nChannels=1;//Monoaural data Recording..For stereo use 2
wfex.nSamplesPerSec=8000;
wfex.wBitsPerSample=8;//can use 16 also for WAVE_FORMAT_PCM
wfex.nBlockAlign=(wfex.nChannels*wfex.wBitsPerSample)/8;
wfex.nAvgBytesPerSec=wfex.nSamplesPerSec*wfex.nBlockAlign;
wfex.cbSize=0;

mRes=waveInOpen(&hWaveIn,0,&wfex,(DWORD)waveInProcHandler,0,CALLBACK_FUNCTION);

ZeroMemory(&wvhdr,sizeof(WAVEHDR));
wvhdr.dwBufferLength=wfex.nAvgBytesPerSec*5;//5 second data

p_Buff=(LPSTR)LocalAlloc(LMEM_FIXED,wvhdr.dwBufferLength);
wvhdr.lpData=p_Buff;
wvhdr.dwFlags=0;

mRes=waveInPrepareHeader(hWaveIn,&wvhdr,sizeof(WAVEHDR));
if(mRes==MMSYSERR_NOERROR)
{
mRes=waveInAddBuffer(hWaveIn,&wvhdr,sizeof(WAVEHDR));
if(mRes==MMSYSERR_NOERROR)
{
mRes=waveInStart(hWaveIn);
if(mRes==MMSYSERR_NOERROR)
{
fRecording=TRUE;
SetDlgItemText(hwnd,IDC_DISPLAYAREA,TEXT("Recording Started..."));
}
else
SetDlgItemText(hwnd,IDC_DISPLAYAREA,TEXT("Recording Not Started"));
}
This code seems to be working as it gives me Recording
Started...notification without any hassels, but thereafter everything
hangs and my STOP button never works and comes out of a hang...

STOP
====
if(fRecording)
{
waveInStop(hWaveIn);
waveInReset(hWaveIn);
waveInUnprepareHeader(hWaveIn,&wvhdr,sizeof(WAVEHDR));
fRecording=FALSE;
SetDlgItemText(hwnd,IDC_DISPLAYAREA,TEXT("Recording Terminated..."));
}

Ideally I guess waveInUnprepareHeader should fire the WIM_DATA event
wherein I have coded as under

case WIM_DATA:
if(fRecording)
{
waveInStop(hWaveIn);
waveInReset(hWaveIn);
waveInUnprepareHeader(hWaveIn,&wvhdr,sizeof(WAVEHDR));
fRecording=FALSE;
}
waveInReset(hWaveIn);
waveInClose(hWaveIn);

Regards
Sid

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