在程序中怎样调节麦克风音量？(更新）

[mountlin]

调节喇叭音量可以用waveOutSetVolume()函数，但却没有waveInSetVolume()函数，那么该怎样编程，实现象netmeeting向导那样调节麦克风音量呢？

[zhq2000]

用 mixerOpen(hMixer,0,0,0) 取得句柄hMixer ， GetVolumeControl(hMixer,MIXERLINE_COMPONENTTYPE_SRC_MICROPHONE,MIXERCONTROL_CONTROLTYPE_VOLUME,
micCtrl) ，然后再用 SetVolumeControl(hMixer,micCtrl, vol /*音量值*/) 就可以了。
详细资料参考MSDN。
程序片段：

BOOL GetVolumeControl(HMIXER hmix,DWORD dwComponentType ,DWORD dwControlType,LPMIXERCONTROL mixCtrl)
{
MIXERLINECONTROLS mixlc;
MIXERLINE mxl;
MMHRESULT res;

ZeroMemory(&mxl,sizeof(mxl));
mxl.cbStruct=sizeof(mxl);
mxl.dwComponentType=dwConponentType;
res=mixerGetLineControls((HMIXEROBJ)hmix,&mxl,MIXER_GETLINECONTROLSF_ONEBYTYPE);
if(res!=MMSYSERR_NOERROR)
return FALSE;

ZeroMemory(mixCtrl,sizeof(MIXERCONTROL));
mixCtrl->cbStruct=sizeof(MIXERCONTROL);

ZeroMemory(&mixlc,sizeof(mixlc));
mixlc.cbStruct=sizeof(mixlc);
mixlc.dwLineID=mxl.dwLineID;
mixlc.dwControl=dwControlType;
mixlc.cControls=1;
mixlc.cbmxctrl=sizeof(MIXERCONTROL);
mix1c.pamxctrl=mixCtrl;

res=mixerGetLineControls((HMIXEROBJ)hmix,mixlc,MIXER_GETLINECONTROLSF_ONEBYTYPE);
if(res!=MMSYSERR_NOERROR)
return FALSE;

return TRUE;
}

BOOL SetVolumeControl(HMIXER hmix,LPMIXERCONTROL mxc,DWORD dwVol)
{
MIXERCONTROLDETAILS mxcd;
MIXERCONTROLDETAILS_UNSIGNED vol;

vol.dwValue=dwVol;

ZeroMemory(&mxcd,sizeof(mxcd));
mxcd.cbStruct=sizeof(mxcd);
mxcd.item=0;
mxcd.cbDetails=sizeof(vol);
mxcd.paDetails=&vol;

MMRESULT res=mixerSetControlDetails((HMIXEROBJ)hmix,&mxcd,MIXER_SETCONTROLDETAILSF_VALUE);

if(res!=MMSYSERR_NOERROR)
return FALSE

return TRUE;
}

HMIXER hMixer;
MMRESULT mmr;
MIXERCONTROL mix
DWORD dwVolume=5050;
mmr=mixerOpen(&hMixer,0,0,0);
if(mmr==MMSYSERR_NOERROR)
{
if(GetVolumeControl( hMixer , MIXERLINE_COMPONENTTYPE_SRC_MICROPHONE , MIXERCONTROL_CONTROLTYPE_VOLUME , &mix))
{
SetVolumeControl(hmixer,&mix,dwVolume);
}
}

[hew]

INT CMixer::ProcessLine(BOOL bIsSet, UINT iCardIndex, DWORD dwType,LPVOID paDetails,DWORD cbDetails,long *plMin,long *plMax)
{
MMRESULT rc; // Return code.
HMIXER hMixer; // Mixer handle used in mixer API calls.
MIXERCONTROL mxc; // Holds the mixer control data.
MIXERLINE mxl; // Holds the mixer line data.
MIXERLINECONTROLS mxlc; // Obtains the mixer control.
// Open the mixer. This opens the mixer with a deviceID of 0. If you
// have a single sound card/mixer, then this will open it. If you have
// multiple sound cards/mixers, the deviceIDs will be 0, 1, 2, and
// so on.
rc = mixerOpen(&hMixer, iCardIndex,0,0,0);
if (MMSYSERR_NOERROR != rc) { // Couldn't open the mixer.
mixerClose(hMixer);
return 1;
}
// Initialize MIXERLINE structure.
ZeroMemory(&mxl,sizeof(mxl));
mxl.cbStruct = sizeof(mxl);
// Specify the line you want to get. You are getting the input line
// here. If you want to get the output line, you need to use
// MIXERLINE_COMPONENTTYPE_SRC_WAVEOUT.
mxl.dwComponentType = dwType;
rc = mixerGetLineInfo((HMIXEROBJ)hMixer, &mxl,
MIXER_GETLINEINFOF_COMPONENTTYPE);
if (MMSYSERR_NOERROR != rc) { // Couldn't get the mixer line.
mixerClose(hMixer);
return 2;
}
// Get the control.
ZeroMemory(&mxlc, sizeof(mxlc));
mxlc.cbStruct = sizeof(mxlc);
mxlc.dwLineID = mxl.dwLineID;
mxlc.dwControlType = MIXERCONTROL_CONTROLTYPE_VOLUME;
mxlc.cControls = 1;
mxlc.cbmxctrl = sizeof(mxc);
mxlc.pamxctrl = &mxc;
ZeroMemory(&mxc, sizeof(mxc));
mxc.cbStruct = sizeof(mxc);
rc = mixerGetLineControls((HMIXEROBJ)hMixer,&mxlc,
MIXER_GETLINECONTROLSF_ONEBYTYPE);
if (MMSYSERR_NOERROR != rc) { // Couldn't get the control.
mixerClose(hMixer);
return 3;
}
if (plMin) *plMin = mxc.Bounds.lMinimum;
if (plMax) *plMax = mxc.Bounds.lMaximum;
// After successfully getting the peakmeter control, the volume range
// will be specified by mxc.Bounds.lMinimum to mxc.Bounds.lMaximum.
MIXERCONTROLDETAILS mxcd; // Gets the control values.
// Initialize the MIXERCONTROLDETAILS structure
ZeroMemory(&mxcd, sizeof(mxcd));
mxcd.cbStruct = sizeof(mxcd);
mxcd.cbDetails = cbDetails;
mxcd.dwControlID = mxc.dwControlID;
mxcd.paDetails = paDetails;
mxcd.cChannels = 1;
// Get the current value of the peakmeter control. Typically, you
// would set a timer in your program to query the volume every 10th
// of a second or so.
if (bIsSet)
{
rc = mixerSetControlDetails((HMIXEROBJ)hMixer, &mxcd,
MIXER_GETCONTROLDETAILSF_VALUE);
if (MMSYSERR_NOERROR != rc) { // Couldn't get the current volume.
mixerClose(hMixer);
return 4;
}
}
else
{
rc = mixerGetControlDetails((HMIXEROBJ)hMixer, &mxcd,
MIXER_GETCONTROLDETAILSF_VALUE);
if (MMSYSERR_NOERROR != rc) { // Couldn't get the current volume.
mixerClose(hMixer);
return 5;
}
}
return 0;
}

STDMETHODIMP CMixer::GetMicVolume(short iCardIndex, long *plVolume, long *plMin, long *plMax)
{
// TODO: Add your implementation code here
MIXERCONTROLDETAILS_SIGNED volStruct;
INT iRet = ProcessLine(FALSE,iCardIndex,
MIXERLINE_COMPONENTTYPE_SRC_MICROPHONE,
&volStruct,sizeof(volStruct),plMin,plMax);
*plVolume = volStruct.lValue;
if (iRet)
return S_FALSE;
else
return S_OK;
}

STDMETHODIMP CMixer::SetMicVolume(short iCardIndex, long lVolume)
{
// TODO: Add your implementation code here
MIXERCONTROLDETAILS_SIGNED volStruct;
volStruct.lValue = lVolume;
INT iRet = ProcessLine(TRUE,iCardIndex,
MIXERLINE_COMPONENTTYPE_SRC_MICROPHONE,
&volStruct,sizeof(volStruct));
if (iRet)
return S_FALSE;
else
return S_OK;
}

STDMETHODIMP CMixer::GetWaveoutVolume(short iCardIndex, long *plVolume, long *plMin, long *plMax)
{
// TODO: Add your implementation code here
MIXERCONTROLDETAILS_SIGNED volStruct;
INT iRet = ProcessLine(FALSE,iCardIndex,
MIXERLINE_COMPONENTTYPE_SRC_WAVEOUT,
&volStruct,sizeof(volStruct),plMin,plMax);
*plVolume = volStruct.lValue;
if (iRet)
return S_FALSE;
else
return S_OK;
}

STDMETHODIMP CMixer::SetWaveoutVolume(short iCardIndex, long lVolume)
{
// TODO: Add your implementation code here
MIXERCONTROLDETAILS_SIGNED volStruct;
volStruct.lValue = lVolume;
INT iRet = ProcessLine(TRUE,iCardIndex,
MIXERLINE_COMPONENTTYPE_SRC_WAVEOUT,
&volStruct,sizeof(volStruct));
if (iRet)
return S_FALSE;
else
return S_OK;
}