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wavein-problems

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Last Modified: 2013-12-04
I wrote the following Callback-Function in order to
add the filled buffer, which is returned by the driver, again to drivers queue. I don't know why it doesn't work.
The driver stopps recording when the buffer is filled.
I would be verry glad if you could help me.

stephan




void CALLBACK  __export  WaveProc(

       HWAVE  hWave,      // handle of waveform device
       UINT  uMsg,      // sent message
       DWORD  dwInstance,      // instance data
       DWORD  dwParam1,      // application-defined parameter
       DWORD  dwParam2      // application-defined parameter
       )
{

 LPWAVEHDR lpWaveHdrTemp = (LPWAVEHDR) dwParam1;

  if( uMsg == WIM_DATA)
       {

             waveInUnprepareHeader((HWAVEIN) hWave, lpWaveHdrTemp ,sizeof(WAVEHDR) ) ;
              waveInPrepareHeader((HWAVEIN)hWave, lpWaveHdrTemp, sizeof(WAVEHDR));
              waveInAddBuffer((HWAVEIN)hWave, lpWaveHdrTemp, sizeof(WAVEHDR));
             
       }
}


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API Reference for WaveProc says:Applications should not call any system-defined functions from inside a callback function, except for EnterCriticalSection, LeaveCriticalSection, midiOutLongMsg, midiOutShortMsg, OutputDebugString, PostMessage, PostThreadMessage, SetEvent, timeGetSystemTime, timeGetTime, timeKillEvent, and timeSetEvent. Calling other wave functions will cause deadlock.

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By the way, I said it before in answer to your question Q861187135 (4/16/97). But 'this question is locked until stephan papadakis evaluates the answer'  :(.

Author

Commented:
Thank's a lot for your answere.

The only problem is, how can i solve my problem?

What should i do know. Should i create a dummy Callback -Window?

If i do so the waveinopen-function returns errorcode 11h

wich means "function is called with wrong parameters".

Author

Commented:
Thank's a lot for your answere.

The only problem is, how can i solve my problem?

What should i do know. Should i create a dummy Callback -Window?

If i do so the waveinopen-function returns errorcode 11h

wich means "function is called with wrong parameters".

To avoid crash, you can try to process buffers in your window procedure, not in the callback function. For example:// Define our notify message#define WMU_FINISHED   (WM_USER+1)// Fill it with handle of our windowHWND wnd;// Callback functionvoid CALLBACK WaveProc(HWAVE hWave, UINT uMsg, DWORD dwInstance, DWORD dwParam1, DWORD dwParam2)
{
  if( uMsg == WIM_DATA) {
      // Device driver is finished!      // Notify our window.      PostMessage(wnd,WMU_FINISHED,0,(LPARAM) dwParam1);   }}// Here is our window procedure... wndProc(HWND hWnd,UINT uMsg,WPARAM wParam,LPARAM lParam){   LPWAVEHDR lpWaveHdrTemp = (LPWAVEHDR) lParam;
  switch(uMsg) {      // ...      case WMU_FINISHED:
          waveInUnprepareHeader((HWAVEIN) hWave, lpWaveHdrTemp, sizeof(WAVEHDR));
          waveInPrepareHeader((HWAVEIN)hWave, lpWaveHdrTemp, sizeof(WAVEHDR));
          waveInAddBuffer((HWAVEIN)hWave, lpWaveHdrTemp, sizeof(WAVEHDR));
      // .....
}Also you can try to use callback window instead of callback function. May be there are no restrictions on calling wave* functions from inside of callback window.P.S. It will be nice if you can post me your source code to nick@rtzi.ru

Author

Commented:
Thank's a lot.

I got it.
The problem is solved.


stephan
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