IPerChannelDbLevel::GetLevelRange method (devicetopology.h)
The GetLevelRange method gets the range, in decibels, of the volume level of the specified channel.
Syntax
HRESULT GetLevelRange(
[in] UINT nChannel,
[out] float *pfMinLevelDB,
[out] float *pfMaxLevelDB,
[out] float *pfStepping
);
Parameters
[in] nChannel
The number of the selected channel. If the audio stream has n channels, the channels are numbered from 0 to n– 1. To get the number of channels in the stream, call the IPerChannelDbLevel::GetChannelCount method.
[out] pfMinLevelDB
Pointer to a float variable into which the method writes the minimum volume level in decibels.
[out] pfMaxLevelDB
Pointer to a float variable into which the method writes the maximum volume level in decibels.
[out] pfStepping
Pointer to a float variable into which the method writes the stepping value between consecutive volume levels in the range *pfMinLevelDB to *pfMaxLevelDB. If the difference between the maximum and minimum volume levels is d decibels, and the range is divided into n steps (uniformly sized intervals), then the volume can have n + 1 discrete levels and the size of the step between consecutive levels is d / n decibels.
Return value
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.
| Return code | Description |
|---|---|
|
Parameter nChannel is out of range. |
|
Pointer pfminLevelDB, pfmaxLevelDB, or pfmaxLevelDB is NULL. |
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows Vista [desktop apps only] |
| Minimum supported server | Windows Server 2008 [desktop apps only] |
| Target Platform | Windows |
| Header | devicetopology.h |