Thank!
to cheka: 安装xing是不理想的步骤
to feng: 用DirectX也会遇到不兼容问题
to jumphigh: 综合来看,还是您的方案好一些
to seeking: mcisendstring是什么东东?!!我还不清楚
to Nicrosoft: 无奈的世界也还是有人有能耐,嘻嘻!
Retrieves the current volume level of the specified waveform-audio output device.
?Returns MMSYSERR_NOERROR if successful or an error otherwise. Possible error values include the following:
MMSYSERR_INVALHANDLE Specified device handle is invalid.
MMSYSERR_NODRIVER No device driver is present.
MMSYSERR_NOMEM Unable to allocate or lock memory.
MMSYSERR_NOTSUPPORTED Function isn't supported.
hwo
Handle of an open waveform-audio output device.
pdwVolume
Address of a variable to be filled with the current volume setting. The low-order word of this location contains the left-channel volume setting, and the high-order word contains the right-channel setting. A value of 0xFFFF represents full volume, and a value of 0x0000 is silence.
If a device does not support both left and right volume control, the low-order word of the specified location contains the mono volume level.
The full 16-bit setting(s) set with the waveOutSetVolume function is returned, regardless of whether the device supports the full 16 bits of volume-level control.
Not all devices support volume changes. To determine whether the device supports volume control, use the WAVECAPS_VOLUME flag to test the dwSupport member of the WAVEOUTCAPS structure (filled by the waveOutGetDevCaps function).
To determine whether the device supports left- and right-channel volume control, use the WAVECAPS_LRVOLUME flag to test the dwSupport member of the WAVEOUTCAPS structure (filled by waveOutGetDevCaps).
Volume settings are interpreted logarithmically. This means the perceived increase in volume is the same when increasing the volume level from 0x5000 to 0x6000 as it is from 0x4000 to 0x5000.
The waveOutSetVolume function sets the volume level of the specified waveform-audio output device.
MMRESULT waveOutSetVolume(
HWAVEOUT hwo,
DWORD dwVolume
);
Parameters
hwo
Handle of an open waveform-audio output device. This parameter can also be a device identifier.
dwVolume
New volume setting. The low-order word contains the left-channel volume setting, and the high-order word contains the right-channel setting. A value of 0xFFFF represents full volume, and a value of 0x0000 is silence.
If a device does not support both left and right volume control, the low-order word of dwVolume specifies the volume level, and the high-order word is ignored.
Return Values
Returns MMSYSERR_NOERROR if successful or an error otherwise. Possible error values include the following:
MMSYSERR_INVALHANDLE Specified device handle is invalid.
MMSYSERR_NODRIVER No device driver is present.
MMSYSERR_NOMEM Unable to allocate or lock memory.
MMSYSERR_NOTSUPPORTED Function is not supported.
Remarks
If a device identifier is used, then the result of the waveOutSetVolume call applies to all instances of the device. If a device handle is used, then the result applies only to the instance of the device referenced by the device handle.
Not all devices support volume changes. To determine whether the device supports volume control, use the WAVECAPS_VOLUME flag to test the dwSupport member of the WAVEOUTCAPS structure (filled by the waveOutGetDevCaps function). To determine whether the device supports volume control on both the left and right channels, use the WAVECAPS_LRVOLUME flag.
Most devices do not support the full 16 bits of volume-level control and will not use the high-order bits of the requested volume setting. For example, for a device that supports 4 bits of volume control, requested volume level values of 0x4000, 0x4FFF, and 0x43BE all produce the same physical volume setting: 0x4000. The waveOutGetVolume function returns the full 16-bit setting set with waveOutSetVolume.
Volume settings are interpreted logarithmically. This means the perceived increase in volume is the same when increasing the volume level from 0x5000 to 0x6000 as it is from 0x4000 to 0x5000.
procedure tform1.trackbar1changer (sender:tobject);//左声道
var t,v:longint;
begin
t:=trackbar1.postion;
wavoutgetvolume(0,@v);
v:=v and $ffff0000 or (t shl 8);
wavoutsetvolume(0,v);
end;
procedure tform1.trackbar2changer (sender:tobject);//右声道
var t,v:longint;
begin
t:=trackbar2.postion;
wavoutgetvolume(0,@v);
v:=v and $0000ffff or (t shl 24);
wavoutsetvolume(0,v);
end;