AAM_EQBandControl

This function controls the gain, center frequency, and bandwidth of each band.

Syntax

DWORD AAM_EQBandControl( DWORD dwIndex, DWORD dwFlags, LONG *plValue );

Parameters

dwIndex

Specifies the index of the band.

dwFlags

Specifies a bitmask for flags. It is one of the following values:

AAM_FLAG_CENTERFREQ: Get or set the center frequency; in hertz.
AAM_FLAG_BANDWIDTH: Get or set the bandwidth; in hertz.
AAM_FLAG_GAIN: Get or set the gain in decibels.

To set a property, use a bitwise OR to combine the chosen flag with AAM_FLAG_SET, and set pValue to the desired value. To get a property, use a bitwise OR to combine the chosen flag with AAM_FLAG_GET and pValue is set to the current value. To get the range, use a bitwise OR to combine the chosen flag with AAM_FLAG_RANGE, and pValue is set to the current value.

plValue

Pointer to the value of dwFlags.

When you combine the AAM_FLAG_RANGE flag with one of the flags specified in dwFlags, pValue represents the following:

For center frequency or bandwidth, the high-order word contains the minimum value and the low-order word contains the maximum value. If these two values are the same, then the value cannot be changed.
For gain, the high-order word has the maximum attenuation level and the low-order word has the maximum gain level. For example, if the gain can be adjusted from -16 to +16, the high-order word contains -16 and the low-order word contains 16.

Return Values

Zero indicates success. AAM_ERR_INVALIDPARAM indicates an invalid parameter. AAM_ERR_DEVICEFAIL indicates failure. AAM_ERR_NOTSUPPORTED indicates that the device does not support this feature.

Remarks

This function is a member of the equalization API. The equalizer only supports decibel-based gain units.