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#ifndef foovolumehfoo
#define foovolumehfoo
/***
This file is part of PulseAudio.
Copyright 2004-2006 Lennart Poettering
Copyright 2006 Pierre Ossman <ossman@cendio.se> for Cendio AB
PulseAudio is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published
by the Free Software Foundation; either version 2 of the License,
or (at your option) any later version.
PulseAudio is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with PulseAudio; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
USA.
***/
#include <inttypes.h>
#include <pulse/cdecl.h>
#include <pulse/gccmacro.h>
#include <pulse/sample.h>
/** \page volume Volume Control
*
* \section overv_sec Overview
*
* Sinks, sources, sink inputs and samples can all have their own volumes.
* To deal with these, The PulseAudio libray contains a number of functions
* that ease handling.
*
* The basic volume type in PulseAudio is the \ref pa_volume_t type. Most of
* the time, applications will use the aggregated pa_cvolume structure that
* can store the volume of all channels at once.
*
* Volumes commonly span between muted (0%), and normal (100%). It is possible
* to set volumes to higher than 100%, but clipping might occur.
*
* \section calc_sec Calculations
*
* The volumes in PulseAudio are logarithmic in nature and applications
* shouldn't perform calculations with them directly. Instead, they should
* be converted to and from either dB or a linear scale:
*
* \li dB - pa_sw_volume_from_dB() / pa_sw_volume_to_dB()
* \li Linear - pa_sw_volume_from_linear() / pa_sw_volume_to_linear()
*
* For simple multiplication, pa_sw_volume_multiply() and
* pa_sw_cvolume_multiply() can be used.
*
* Calculations can only be reliably performed on software volumes
* as it is commonly unknown what scale hardware volumes relate to.
*
* The functions described above are only valid when used with
* software volumes. Hence it is usually a better idea to treat all
* volume values as opaque with a range from PA_VOLUME_MUTE (0%) to
* PA_VOLUME_NORM (100%) and to refrain from any calculations with
* them.
*
* \section conv_sec Convenience Functions
*
* To handle the pa_cvolume structure, the PulseAudio library provides a
* number of convenienc functions:
*
* \li pa_cvolume_valid() - Tests if a pa_cvolume structure is valid.
* \li pa_cvolume_equal() - Tests if two pa_cvolume structures are identical.
* \li pa_cvolume_channels_equal_to() - Tests if all channels of a pa_cvolume
* structure have a given volume.
* \li pa_cvolume_is_muted() - Tests if all channels of a pa_cvolume
* structure are muted.
* \li pa_cvolume_is_norm() - Tests if all channels of a pa_cvolume structure
* are at a normal volume.
* \li pa_cvolume_set() - Set all channels of a pa_cvolume structure to a
* certain volume.
* \li pa_cvolume_reset() - Set all channels of a pa_cvolume structure to a
* normal volume.
* \li pa_cvolume_mute() - Set all channels of a pa_cvolume structure to a
* muted volume.
* \li pa_cvolume_avg() - Return the average volume of all channels.
* \li pa_cvolume_snprint() - Pretty print a pa_cvolume structure.
*/
/** \file
* Constants and routines for volume handling */
PA_C_DECL_BEGIN
/** Volume specification:
* PA_VOLUME_MUTED: silence;
* < PA_VOLUME_NORM: decreased volume;
* PA_VOLUME_NORM: normal volume;
* > PA_VOLUME_NORM: increased volume */
typedef uint32_t pa_volume_t;
/** Normal volume (100%) */
#define PA_VOLUME_NORM ((pa_volume_t) 0x10000U)
/** Muted volume (0%) */
#define PA_VOLUME_MUTED ((pa_volume_t) 0U)
/** A structure encapsulating a per-channel volume */
typedef struct pa_cvolume {
uint8_t channels; /**< Number of channels */
pa_volume_t values[PA_CHANNELS_MAX]; /**< Per-channel volume */
} pa_cvolume;
/** Return non-zero when *a == *b */
int pa_cvolume_equal(const pa_cvolume *a, const pa_cvolume *b) PA_GCC_PURE;
/** Set the volume of all channels to PA_VOLUME_NORM */
#define pa_cvolume_reset(a, n) pa_cvolume_set((a), (n), PA_VOLUME_NORM)
/** Set the volume of all channels to PA_VOLUME_MUTED */
#define pa_cvolume_mute(a, n) pa_cvolume_set((a), (n), PA_VOLUME_MUTED)
/** Set the volume of all channels to the specified parameter */
pa_cvolume* pa_cvolume_set(pa_cvolume *a, unsigned channels, pa_volume_t v);
/** Maximum length of the strings returned by pa_cvolume_snprint() */
#define PA_CVOLUME_SNPRINT_MAX 64
/** Pretty print a volume structure */
char *pa_cvolume_snprint(char *s, size_t l, const pa_cvolume *c);
/** Return the average volume of all channels */
pa_volume_t pa_cvolume_avg(const pa_cvolume *a) PA_GCC_PURE;
/** Return TRUE when the passed cvolume structure is valid, FALSE otherwise */
int pa_cvolume_valid(const pa_cvolume *v) PA_GCC_PURE;
/** Return non-zero if the volume of all channels is equal to the specified value */
int pa_cvolume_channels_equal_to(const pa_cvolume *a, pa_volume_t v) PA_GCC_PURE;
/** Return 1 if the specified volume has all channels muted */
#define pa_cvolume_is_muted(a) pa_cvolume_channels_equal_to((a), PA_VOLUME_MUTED)
/** Return 1 if the specified volume has all channels on normal level */
#define pa_cvolume_is_norm(a) pa_cvolume_channels_equal_to((a), PA_VOLUME_NORM)
/** Multiply two volumes specifications, return the result. This uses PA_VOLUME_NORM as neutral element of multiplication. This is only valid for software volumes! */
pa_volume_t pa_sw_volume_multiply(pa_volume_t a, pa_volume_t b) PA_GCC_CONST;
/** Multiply to per-channel volumes and return the result in *dest. This is only valid for software volumes! */
pa_cvolume *pa_sw_cvolume_multiply(pa_cvolume *dest, const pa_cvolume *a, const pa_cvolume *b);
/** Convert a decibel value to a volume. This is only valid for software volumes! */
pa_volume_t pa_sw_volume_from_dB(double f) PA_GCC_CONST;
/** Convert a volume to a decibel value. This is only valid for software volumes! */
double pa_sw_volume_to_dB(pa_volume_t v) PA_GCC_CONST;
/** Convert a linear factor to a volume. This is only valid for software volumes! */
pa_volume_t pa_sw_volume_from_linear(double v) PA_GCC_CONST;
/** Convert a volume to a linear factor. This is only valid for software volumes! */
double pa_sw_volume_to_linear(pa_volume_t v) PA_GCC_CONST;
#ifdef INFINITY
#define PA_DECIBEL_MININFTY ((double) -INFINITY)
#else
/** This value is used as minus infinity when using pa_volume_{to,from}_dB(). */
#define PA_DECIBEL_MININFTY ((double) -200.0)
#endif
PA_C_DECL_END
#endif
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