Mapping ISpMMSysAudio::SetLineId and mixerLineId

Question

I want to set the lineId for SAPI by calling ISpMMSysAudio::SetLineId. I find out the line which I wish to set from the mixer handle I have. However the line id I get from the mixer is not what SAPI assumes. It results in SAPI listening to the wrong input line for mic thus getting no input.

I'm getting the mux control for "DST_WAVEIN" for the mixer handle and then checking which source line for microphone is active. I wish to set the active line as "input" to the SAPI.

I am getting Line Id from mixer by enumerating MUX control as follows:

int GetSelectedWaveInLine(UINT uMixrId) { int iRetVal = -1; MMRESULT mmResult; HMIXER dwMixerHandle;

mmResult = mixerOpen( (LPHMIXER)&dwMixerHandle, uMixrId, 0L, 0L, 0L);
if (MMSYSERR_NOERROR != mmResult)
{ 
 LOG_ERROR("FAILURE: Could not Open mixer, with id: %d. mmResult=%d",uMixrId, mmResult );
 return -1;
}

MIXERLINE MixerLine;
memset( &MixerLine, 0, sizeof(MIXERLINE) );
MixerLine.cbStruct = sizeof(MIXERLINE);
MixerLine.dwComponentType = MIXERLINE_COMPONENTTYPE_DST_WAVEIN;
mmResult = mixerGetLineInfo( (HMIXEROBJ)dwMixerHandle, &MixerLine, MIXER_GETLINEINFOF_COMPONENTTYPE );
if (MMSYSERR_NOERROR != mmResult)
{
 mixerClose( (HMIXER)dwMixerHandle );
 LOG_ERROR("FAILURE: Could not get WaveIn Destionation Line for the requested source while enumerating. mmResult=%d", mmResult );
 return -1;
}

// get the MUX
MIXERCONTROL mxc;
MIXERLINECONTROLS mxlc;
mxlc.cbStruct = sizeof(MIXERLINECONTROLS);
mxlc.dwLineID = MixerLine.dwLineID;
mxlc.dwControlType = MIXERCONTROL_CONTROLTYPE_MUX;
mxlc.cControls = 1;
mxlc.cbmxctrl = sizeof(MIXERCONTROL);
mxlc.pamxctrl = &mxc;
mmResult = ::mixerGetLineControls(reinterpret_cast<HMIXEROBJ>(uMixrId),
         &mxlc,
         MIXER_OBJECTF_HMIXER |
         MIXER_GETLINECONTROLSF_ONEBYTYPE);
if (MMSYSERR_NOERROR != mmResult)
{
 LOG_INFO0("Could not get Mux control for waveIn line. Get selected id");
 mixerClose( (HMIXER)dwMixerHandle );
 return -1;
}
LOG_INFO("Got mux controls. Total lines associated with mux = %d", mxc.cMultipleItems); 

// from the MUX get as many lines for "MIXERLINE_COMPONENTTYPE_SRC_MICROPHONE" {from dwParam1/dwParam2 }
// then get the boolean control for the line and return the one currently selected
MIXERCONTROLDETAILS_LISTTEXT *pmxcdSelectText = new MIXERCONTROLDETAILS_LISTTEXT[mxc.cMultipleItems];
if (pmxcdSelectText != NULL)
{
 MIXERCONTROLDETAILS mxcd;
 mxcd.cbStruct = sizeof(MIXERCONTROLDETAILS);
 mxcd.dwControlID = mxc.dwControlID;
 mxcd.cChannels = 1;
 mxcd.cMultipleItems = mxc.cMultipleItems;
 mxcd.cbDetails = sizeof(MIXERCONTROLDETAILS_LISTTEXT);
 mxcd.paDetails = pmxcdSelectText;
 if (::mixerGetControlDetails(reinterpret_cast<HMIXEROBJ>(uMixrId),
         &mxcd,
         MIXER_OBJECTF_HMIXER |
         MIXER_GETCONTROLDETAILSF_LISTTEXT)
  != MMSYSERR_NOERROR)
 {
  delete []pmxcdSelectText;
  mixerClose( (HMIXER)dwMixerHandle );
  return -1;
 }
}

//get all the boolean values for the mux
MIXERCONTROLDETAILS_BOOLEAN *pmxcdSelectValue = new MIXERCONTROLDETAILS_BOOLEAN[mxc.cMultipleItems];
if (pmxcdSelectValue != NULL)
{
 MIXERCONTROLDETAILS mxcd;
 mxcd.cbStruct = sizeof(MIXERCONTROLDETAILS);
 mxcd.dwControlID = mxc.dwControlID;
 mxcd.cChannels = 1;
 mxcd.cMultipleItems = mxc.cMultipleItems;
 mxcd.cbDetails = sizeof(MIXERCONTROLDETAILS_BOOLEAN);
 mxcd.paDetails = pmxcdSelectValue;
 if (::mixerGetControlDetails(reinterpret_cast<HMIXEROBJ>(uMixrId),
         &mxcd,
         MIXER_OBJECTF_HMIXER |
         MIXER_GETCONTROLDETAILSF_VALUE)
  != MMSYSERR_NOERROR)
 {
  delete []pmxcdSelectValue;
  mixerClose( (HMIXER)dwMixerHandle );
  return -1;
 }
}

for (int i = 0; i < mxc.cMultipleItems; i++)
{
 if(/*(pmxcdSelectText[i].dwParam2 == MIXERLINE_COMPONENTTYPE_SRC_MICROPHONE) && */pmxcdSelectValue[i].fValue)
 {
  LOG_INFO("Got SELECTED microphone source line. Line index = %d, Line name = %s",i,pmxcdSelectText[i].szName); 
  iRetVal  = i;
  break;
 }
}
//LOG_INFO("Got mux controls. Total lines associated with mux = %d", mxc.cMultipleItems); 
delete []pmxcdSelectText;
delete []pmxcdSelectValue;
mixerClose( (HMIXER)dwMixerHandle );
return iRetVal;

}

The index returned by Mixer does not match the index used by ISpMMSysAudio. And my speech engine picks different line ID.

Thanks

Answer 1

ISpMMSysAudio::SetLineId actually specifies the mixer index, not the line ID. (Confusing, I know.) So what you want to do is to enumerate the mixer lines to find the index that corresponds to the line ID, and return the index.