IAudioStreamVolume::SetAllVolumes method (audioclient.h)
The SetAllVolumes method sets the individual volume levels for all the channels in the audio stream.
HRESULT SetAllVolumes( UINT32 dwCount, const float *pfVolumes );
The number of elements in the pfVolumes array. This parameter must equal the number of channels in the stream format. To get the number of channels, call the IAudioStreamVolume::GetChannelCount method.
Pointer to an array of volume levels for the channels in the audio stream. The number of elements in the pfVolumes array is specified by the dwCount parameter. The caller writes the volume level for each channel to the array element whose index matches the channel number. If the stream format has N channels, the channels are numbered from 0 to N– 1. Valid volume levels are in the range 0.0 to 1.0.
If the method succeeds, it returns S_OK. If it fails, possible return codes include, but are not limited to, the values shown in the following table.
||Parameter dwCount does not equal the number of channels in the stream, or the value of a pfVolumes array element is not in the range 0.0 to 1.0.|
||Parameter pfVolumes is NULL.|
||The audio endpoint device has been unplugged, or the audio hardware or associated hardware resources have been reconfigured, disabled, removed, or otherwise made unavailable for use.|
||The Windows audio service is not running.|
|Minimum supported client||Windows Vista [desktop apps only]|
|Minimum supported server||Windows Server 2008 [desktop apps only]|