mpg123 volume and equalizer

Enumerations
enum	mpg123_channels {   MPG123_LEFT =0x1 , MPG123_RIGHT =0x2 ,   MPG123_LR =0x3 }

Functions
MPG123_EXPORT int	mpg123_eq (mpg123_handle *mh, enum mpg123_channels channel, int band, double val)
MPG123_EXPORT int	mpg123_eq2 (mpg123_handle *mh, int channel, int band, double val)
MPG123_EXPORT int	mpg123_eq_bands (mpg123_handle *mh, int channel, int a, int b, double factor)
MPG123_EXPORT int	mpg123_eq_change (mpg123_handle *mh, int channel, int a, int b, double db)
MPG123_EXPORT double	mpg123_geteq (mpg123_handle *mh, enum mpg123_channels channel, int band)
MPG123_EXPORT double	mpg123_geteq2 (mpg123_handle *mh, int channel, int band)
MPG123_EXPORT int	mpg123_reset_eq (mpg123_handle *mh)
MPG123_EXPORT int	mpg123_volume (mpg123_handle *mh, double vol)
MPG123_EXPORT int	mpg123_volume_change (mpg123_handle *mh, double change)
MPG123_EXPORT int	mpg123_volume_change_db (mpg123_handle *mh, double db)
MPG123_EXPORT int	mpg123_getvolume (mpg123_handle *mh, double *base, double *really, double *rva_db)

Detailed Description

Enumeration Type Documentation

mpg123_channels

enum mpg123_channels

another channel enumeration, for left/right choice

Enumerator
MPG123_LEFT	The Left Channel.
MPG123_RIGHT	The Right Channel.
MPG123_LR	Both left and right channel; same as MPG123_LEFT|MPG123_RIGHT

Definition at line 1219 of file mpg123.h.

Function Documentation

mpg123_eq()

MPG123_EXPORT int mpg123_eq	(	mpg123_handle *	mh,
		enum mpg123_channels	channel,
		int	band,
		double	val
	)

Set the 32 Band Audio Equalizer settings.

Note that this name is mapped to mpg123_eq2() instead unless MPG123_ENUM_API is defined.

Parameters

mh	handle
channel	Can be MPG123_LEFT, MPG123_RIGHT or MPG123_LEFT|MPG123_RIGHT for both.
band	The equaliser band to change (from 0 to 31)
val	The (linear) adjustment factor.

Returns

MPG123_OK on success

mpg123_eq2()

MPG123_EXPORT int mpg123_eq2	(	mpg123_handle *	mh,
		int	channel,
		int	band,
		double	val
	)

Set the 32 Band Audio Equalizer settings. No enums.

This is actually called instead of mpg123_eq() unless MPG123_ENUM_API is defined.

Parameters

mh	handle
channel	Can be MPG123_LEFT, MPG123_RIGHT or MPG123_LEFT|MPG123_RIGHT for both.
band	The equaliser band to change (from 0 to 31)
val	The (linear) adjustment factor.

Returns

MPG123_OK on success

mpg123_eq_bands()

MPG123_EXPORT int mpg123_eq_bands	(	mpg123_handle *	mh,
		int	channel,
		int	a,
		int	b,
		double	factor
	)

Set a range of equalizer bands

Parameters

channel	Can be MPG123_LEFT, MPG123_RIGHT or MPG123_LEFT|MPG123_RIGHT for both.
a	The first equalizer band to set (from 0 to 31)
b	The last equalizer band to set (from 0 to 31)
factor	The (linear) adjustment factor, 1 being neutral.

Returns

MPG123_OK on success

mpg123_eq_change()

MPG123_EXPORT int mpg123_eq_change	(	mpg123_handle *	mh,
		int	channel,
		int	a,
		int	b,
		double	db
	)

Change a range of equalizer bands

Parameters

channel	Can be MPG123_LEFT, MPG123_RIGHT or MPG123_LEFT|MPG123_RIGHT for both.
a	The first equalizer band to change (from 0 to 31)
b	The last equalizer band to change (from 0 to 31)
db	The adjustment in dB (limited to +/- 60 dB).

Returns

MPG123_OK on success

mpg123_geteq()

MPG123_EXPORT double mpg123_geteq	(	mpg123_handle *	mh,
		enum mpg123_channels	channel,
		int	band
	)

Get the 32 Band Audio Equalizer settings.

Note that this name is mapped to mpg123_geteq2() instead unless MPG123_ENUM_API is defined.

Parameters

mh	handle
channel	Can be MPG123_LEFT, MPG123_RIGHT or MPG123_LEFT|MPG123_RIGHT for (arithmetic mean of) both.
band	The equaliser band to change (from 0 to 31)

Returns

The (linear) adjustment factor (zero for pad parameters)

mpg123_geteq2()

MPG123_EXPORT double mpg123_geteq2	(	mpg123_handle *	mh,
		int	channel,
		int	band
	)

Get the 32 Band Audio Equalizer settings.

This is actually called instead of mpg123_geteq() unless MPG123_ENUM_API is defined.

Parameters

mh	handle
channel	Can be MPG123_LEFT, MPG123_RIGHT or MPG123_LEFT|MPG123_RIGHT for (arithmetic mean of) both.
band	The equaliser band to change (from 0 to 31)

Returns

The (linear) adjustment factor (zero for pad parameters)

mpg123_reset_eq()

MPG123_EXPORT int mpg123_reset_eq

(

mpg123_handle *

mh

)

Reset the 32 Band Audio Equalizer settings to flat

Parameters

mh

handle

Returns

MPG123_OK on success

mpg123_volume()

MPG123_EXPORT int mpg123_volume	(	mpg123_handle *	mh,
		double	vol
	)

Set the absolute output volume including the RVA setting, vol<0 just applies (a possibly changed) RVA setting.

Parameters

mh	handle
vol	volume value (linear factor)

Returns

MPG123_OK on success

mpg123_volume_change()

MPG123_EXPORT int mpg123_volume_change	(	mpg123_handle *	mh,
		double	change
	)

Adjust output volume including the RVA setting by chosen amount

Parameters

mh	handle
change	volume value (linear factor increment)

Returns

MPG123_OK on success

mpg123_volume_change_db()

MPG123_EXPORT int mpg123_volume_change_db	(	mpg123_handle *	mh,
		double	db
	)

Adjust output volume including the RVA setting by chosen amount

Parameters

mh	handle
db	volume adjustment in decibels (limited to +/- 60 dB)

Returns

MPG123_OK on success

mpg123_getvolume()

MPG123_EXPORT int mpg123_getvolume	(	mpg123_handle *	mh,
		double *	base,
		double *	really,
		double *	rva_db
	)

Return current volume setting, the actual value due to RVA, and the RVA adjustment itself. It's all as double float value to abstract the sample format. The volume values are linear factors / amplitudes (not percent) and the RVA value is in decibels.

Parameters

mh	handle
base	return address for base volume (linear factor)
really	return address for actual volume (linear factor)
rva_db	return address for RVA value (decibels)

Returns

MPG123_OK on success