我在编写音量控制的代码时,碰到一个问题.
当调整volume音量时,左右声道的平衡会突然变到左声道.
不知道这是为什么？
代码如下
void CMixer::SetVolume(DWORD dwVol)
{
HMIXER hMixer;
HRESULT hr;
hr = mixerOpen(&hMixer, 0, 0, 0, 0);
if (FAILED(hr)) return; MIXERCONTROLDETAILS mxcd;
MIXERCONTROLDETAILS_UNSIGNED mxdu; mxdu.dwValue = dwVol; mxcd.cMultipleItems = 0;
mxcd.cChannels = m_dwChannels;//全局变量，保存声道数
mxcd.cbStruct = sizeof(mxcd);
mxcd.dwControlID = m_dwControlID;//全局变量
mxcd.cbDetails = sizeof(mxdu);
mxcd.paDetails = &mxdu;
hr = mixerSetControlDetails((HMIXEROBJ)hMixer, &mxcd, MIXER_SETCONTROLDETAILSF_VALUE);
mixerClose(hMixer);
}
请高手指教
当调整volume音量时,左右声道的平衡会突然变到左声道.
不知道这是为什么？
代码如下
void CMixer::SetVolume(DWORD dwVol)
{
HMIXER hMixer;
HRESULT hr;
hr = mixerOpen(&hMixer, 0, 0, 0, 0);
if (FAILED(hr)) return; MIXERCONTROLDETAILS mxcd;
MIXERCONTROLDETAILS_UNSIGNED mxdu; mxdu.dwValue = dwVol; mxcd.cMultipleItems = 0;
mxcd.cChannels = m_dwChannels;//全局变量，保存声道数
mxcd.cbStruct = sizeof(mxcd);
mxcd.dwControlID = m_dwControlID;//全局变量
mxcd.cbDetails = sizeof(mxdu);
mxcd.paDetails = &mxdu;
hr = mixerSetControlDetails((HMIXEROBJ)hMixer, &mxcd, MIXER_SETCONTROLDETAILSF_VALUE);
mixerClose(hMixer);
}
请高手指教
#include <mmsystem.h> 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, 0,0,0,0);
if (MMSYSERR_NOERROR == rc) {
// Couldn't open the mixer.
} // 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 = MIXERLINE_COMPONENTTYPE_DST_WAVEIN; rc = mixerGetLineInfo((HMIXEROBJ)hMixer, &mxl,
MIXER_GETLINEINFOF_COMPONENTTYPE);
if (MMSYSERR_NOERROR == rc) {
// Couldn't get the mixer line.
} // Get the control.
ZeroMemory(&mxlc, sizeof(mxlc));
mxlc.cbStruct = sizeof(mxlc);
mxlc.dwLineID = mxl.dwLineID;
mxlc.dwControlType = MIXERCONTROL_CONTROLTYPE_PEAKMETER;
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.
} // 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.
MIXERCONTROLDETAILS_SIGNED volStruct; // Gets the control values.
long volume; // Holds the final volume value. // Initialize the MIXERCONTROLDETAILS structure
ZeroMemory(&mxcd, sizeof(mxcd));
mxcd.cbStruct = sizeof(mxcd);
mxcd.cbDetails = sizeof(volStruct);
mxcd.dwControlID = mxc.dwControlID;
mxcd.paDetails = &volStruct;
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.
rc = mixerGetControlDetails((HMIXEROBJ)hMixer, &mxcd,
MIXER_GETCONTROLDETAILSF_VALUE);
if (MMSYSERR_NOERROR == rc) {
// Couldn't get the current volume.
}
volume = volStruct.lValue; // Get the absolute value of the volume.
if (volume < 0)
volume = -volume;