Level Control

The level control value determines the full scale reference level (also known as trim) of an analog input or output. More...

Functions
hpi_err_t	HPI_LevelQueryRange (const hpi_hsubsys_t *phSubSys, hpi_handle_t hControl, short *nMinGain_01dB, short *nMaxGain_01dB, short *nStepGain_01dB)
	Query the allowed values of a level control.
hpi_err_t	HPI_LevelSetGain (const hpi_hsubsys_t *phSubSys, hpi_handle_t hControl, short anGain0_01dB[HPI_MAX_CHANNELS])
	Sets the value of a level control.
hpi_err_t	HPI_LevelGetGain (const hpi_hsubsys_t *phSubSys, hpi_handle_t hControl, short anGain0_01dB[HPI_MAX_CHANNELS])
	Gets the value of a level control.

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Detailed Description

The level control value determines the full scale reference level (also known as trim) of an analog input or output.

This is the signal level that corresponds to digital full scale (0dB peak).

The level control value is set in units of 0.01dBu (0dBu = 0.775 VRMS). For example a value of 1400 is 14dBu.

Note:

The level control is not a gain control. In particular, increasing an input level reduces the apparent input signal.

Control type: HPI_CONTROL_LEVEL

Found on node types: HPI_SOURCENODE_LINEIN, HPI_SOURCENODE_ANALOG, HPI_SOURCENODE_MICROPHONE, HPI_DESTNODE_LINEOUT, HPI_DESTNODE_ANALOG,

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Function Documentation

hpi_err_t HPI_LevelQueryRange	(	const hpi_hsubsys_t *	phSubSys,
		hpi_handle_t	hControl,
		short *	nMinGain_01dB,
		short *	nMaxGain_01dB,
		short *	nStepGain_01dB
	)

Query the allowed values of a level control.

Gets the minimum, maximum and step of the specified level control.

Returns:

0 on success, or one of the HPI_ERROR_CODES.

Parameters:

phSubSys	Vestigial subsys handle (unused), may be set to NULL
hControl	Handle to level control.
nMinGain_01dB	Minimum level setting in 100ths of a dBu.
nMaxGain_01dB	Maximum level setting in 100ths of a dBu.
nStepGain_01dB	Step size in 100ths of a dBu.

hpi_err_t HPI_LevelSetGain	(	const hpi_hsubsys_t *	phSubSys,
		hpi_handle_t	hControl,
		short	anGain0_01dB[HPI_MAX_CHANNELS]
	)

Sets the value of a level control.

Returns:

0 on success, or one of the HPI_ERROR_CODES.

Parameters:

phSubSys	Vestigial subsys handle (unused), may be set to NULL
hControl	Handle to control of type HPI_CONTROL_LEVEL.
anGain0_01dB	Array containing the stereo level control value. Index 0 is the left channel and index 1 is the right channel.

hpi_err_t HPI_LevelGetGain	(	const hpi_hsubsys_t *	phSubSys,
		hpi_handle_t	hControl,
		short	anGain0_01dB[HPI_MAX_CHANNELS]
	)

Gets the value of a level control.

Returns:

0 on success, or one of the HPI_ERROR_CODES.

Parameters:

phSubSys	Vestigial subsys handle (unused), may be set to NULL
hControl	Handle to control of type HPI_CONTROL_LEVEL.
anGain0_01dB	Array containing the stereo level control value. Index 0 is the left channel and index 1 is the right channel.