| #ifndef foovolumehfoo |
| #define foovolumehfoo |
| |
| /* $Id: volume.h 1971 2007-10-28 19:13:50Z lennart $ */ |
| |
| /*** |
| 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/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 (0x10000) |
| |
| /** Muted volume (0%) */ |
| #define PA_VOLUME_MUTED (0) |
| |
| /** 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) PA_GCC_PURE; |
| |
| /** Convert a decibel value to a volume. This is only valid for software volumes! \since 0.4 */ |
| 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! \since 0.4 */ |
| 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! \since 0.8 */ |
| 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! \since 0.8 */ |
| double pa_sw_volume_to_linear(pa_volume_t v) PA_GCC_CONST; |
| |
| #ifdef INFINITY |
| #define PA_DECIBEL_MININFTY (-INFINITY) |
| #else |
| /** This value is used as minus infinity when using pa_volume_{to,from}_dB(). \since 0.4 */ |
| #define PA_DECIBEL_MININFTY (-200) |
| #endif |
| |
| PA_C_DECL_END |
| |
| #endif |