?
Solved

Problems with double / multiple buffering for low level wave input

Posted on 1997-09-22
6
Medium Priority
?
1,128 Views
Last Modified: 2013-12-04
Hi,
I am trying to get realtime throughput of the wave input to the wave output in full duplex.  I am using the code suggested by Creative Lab examples.  It works , except that in my MM_WIM_DATA  when I have passed on the buffer to the output, and unprepared the input header, preparing the just received buffer to recycle it for adding into the input queue seems to give problems. Error no. 7 memory alloc error.
here is the code for my mem allocation, start of input, and the function for processing MM_WIM_DATA.

      for (int i = 0; i < MAX_BUFFERS; i++)
      {
      
            hWaveInHdr[i] = GlobalAlloc(GHND | GMEM_SHARE, sizeof(WAVEHDR));
            lpWaveInHdr[i] = (LPWAVEHDR) GlobalLock(hWaveInHdr[i]);
            hWaveInBuffer[i] = GlobalAlloc(GHND | GMEM_SHARE, BUFFER_SIZE);
            lpWaveInBuffer[i] = (LPSTR) GlobalLock(hWaveInBuffer[i]);
            lpWaveInHdr[i]->lpData = lpWaveInBuffer[i];
            lpWaveInHdr[i]->dwBufferLength = BUFFER_SIZE;

            hWaveOutBuffer[i] = GlobalAlloc(GHND | GMEM_SHARE, BUFFER_SIZE);
            lpWaveOutBuffer[i] = (LPSTR) GlobalLock(hWaveOutBuffer[i]);
            hWaveOutHdr[i] = GlobalAlloc(GHND | GMEM_SHARE, sizeof(WAVEHDR));
            lpWaveOutHdr[i] = (LPWAVEHDR) GlobalLock(hWaveOutHdr[i]);
            lpWaveOutHdr[i]->lpData = lpWaveInBuffer[i];
            lpWaveOutHdr[i]->dwBufferLength = BUFFER_SIZE;

      }



///////////////////////////////////////////////////////////
      // Prepare and send input buffers to input device
      /////////////////////////
      nBufferIn = 0;
      nBufferOut = 0;
      for(int i=0; i<MAX_BUFFERS; i++)
      {
            // Prepare wave in header
            if (waveInPrepareHeader(hWaveIn, lpWaveInHdr[i], sizeof(WAVEHDR)))
            {
                  AfxMessageBox("OnPlay-error preparing header");
            }
            // Add buffer to recording queue
            if (waveInAddBuffer(hWaveIn, lpWaveInHdr[i], sizeof(WAVEHDR)))
            {
                  AfxMessageBox("OnPlay-error adding buffer");
            }
            else nBufferIn++;
      }


      // Start the wave input - begin sampling
      ///////////////////////
      waveInStart(hWaveIn);
      CDC* pDC = GetDC();
      pDC->TextOut(100,100,"Wave Started");
      ReleaseDC(pDC);


///////////////////////////////////////////////////////////
LONG CCreativeAudioView::OnMMWIMDATA (UINT wParam, LONG lParam)
{
//  Procedure to handle message from device driver saying it has filled a buffer
//  code from creative labs sample code

 nBufferIn--;
LPWAVEHDR lpWaveHdrTmp;
 lpWaveHdrTemp = (LPWAVEHDR) lParam;
lpWaveHdrTempOut = (LPWAVEHDR) lParam;
waveInUnprepareHeader(hWaveIn, lpWaveHdrTemp, sizeof(WAVEHDR));

// Send received buffer to output queue
      ///////////////////////////////////////////////////////////////
    waveOutPrepareHeader(hWaveOut, ((LPWAVEHDR) lParam),sizeof(WAVEHDR));
    waveOutWrite(hWaveOut, ((LPWAVEHDR) lParam), sizeof(WAVEHDR));
      
      //add another buffer to input queue
//////   THIS IS WHERE THE PROBLEMS COME IN, IT WORKS FOR 16 BUFFERS AND THEN SOUND STOPS AND I GET ERROR 7 EACH TIME I TRY TO PREPARE THE HEADER///////////      ////////////////////////////////////////////////////////
nError = waveInPrepareHeader( hWaveIn, lpWaveHdrTmp, sizeof(WAVEHDR));
if (nError != 0)
{
      strMessageText.Format("Error preparing next input header %d", nError);
      AfxMessageBox(strMessageText);
};
waveInAddBuffer(hWaveIn, lpWaveHdrTemp, sizeof(WAVEHDR));
nBufferIn++;
      return 0L;
}


i'D BE GRATEFUL FOR ANY HELP
Thanks

Kingpie
0
Comment
Question by:kingpie
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
  • 2
6 Comments
 
LVL 5

Expert Comment

by:y96andha
ID: 1406974
Does the waveinunprepareheader always succeed? Do you unprepare the waveout buffers?
0
 
LVL 2

Accepted Solution

by:
alexxx earned 100 total points
ID: 1406975
Since you use the same buffers for both recording (wave in) and playback (wave out) you should synchronize their sending to these devices. Don't add buffers to wave in in its callback. Instead register callback function for wave out device and add buffer returned from wave out back to wave in. The data won't be lost because there are several buffers.


->Wave In-->(Wave In callback)-->Wave Out-->(Wave Out callback)-
^---<

0
 

Author Comment

by:kingpie
ID: 1406976
It seems that waveInUnprepareHeader does always work.  The wave out buffers are unprepared in OnMM_WOM_DONE:

LONG CCreativeAudioView::OnMMWOMDONE (UINT wParam, LONG lParam)
{      
      lpWaveHdrTempOut = (LPWAVEHDR) lParam;
      waveOutUnprepareHeader(hWaveOut, lpWaveHdrTempOut,         sizeof(WAVEHDR));
      return 0L;
}
0
Free learning courses: Active Directory Deep Dive

Get a firm grasp on your IT environment when you learn Active Directory best practices with Veeam! Watch all, or choose any amount, of this three-part webinar series to improve your skills. From the basics to virtualization and backup, we got you covered.

 

Author Comment

by:kingpie
ID: 1406977
It seems that waveInUnprepareHeader does always work.  The wave out buffers are unprepared in OnMM_WOM_DONE:

LONG CCreativeAudioView::OnMMWOMDONE (UINT wParam, LONG lParam)
{      
      lpWaveHdrTempOut = (LPWAVEHDR) lParam;
      waveOutUnprepareHeader(hWaveOut, lpWaveHdrTempOut,         sizeof(WAVEHDR));
      return 0L;
}
0
 
LVL 2

Expert Comment

by:alexxx
ID: 1406978
So add buffers to Wave In on MM_WOM_DONE too and everything should be OK.
Good luck!
0
 

Author Comment

by:kingpie
ID: 1406979
It works!  thanks very much. (and it makes sense!)
KingPie
0

Featured Post

Free Tool: IP Lookup

Get more info about an IP address or domain name, such as organization, abuse contacts and geolocation.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

With most software applications trying to cater to multiple user needs nowadays, the focus is to make them as configurable as possible. For e.g., when creating Silverlight applications which will connect to WCF services, the service end point usuall…
A theme is a collection of property settings that allow you to define the look of pages and controls, and then apply the look consistently across pages in an application. Themes can be made up of a set of elements: skins, style sheets, images, and o…
This is Part 3 in a 3-part series on Experts Exchange to discuss error handling in VBA code written for Excel. Part 1 of this series discussed basic error handling code using VBA. http://www.experts-exchange.com/videos/1478/Excel-Error-Handlin…
Sometimes it takes a new vantage point, apart from our everyday security practices, to truly see our Active Directory (AD) vulnerabilities. We get used to implementing the same techniques and checking the same areas for a breach. This pattern can re…

770 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question