code.delx.au - pulseaudio/blob - src/pulse/volume.h

   1 #ifndef foovolumehfoo
   2 #define foovolumehfoo
   3
   4 /***
   5   This file is part of PulseAudio.
   6
   7   Copyright 2004-2006 Lennart Poettering
   8   Copyright 2006 Pierre Ossman <ossman@cendio.se> for Cendio AB
   9
  10   PulseAudio is free software; you can redistribute it and/or modify
  11   it under the terms of the GNU Lesser General Public License as published
  12   by the Free Software Foundation; either version 2 of the License,
  13   or (at your option) any later version.
  14
  15   PulseAudio is distributed in the hope that it will be useful, but
  16   WITHOUT ANY WARRANTY; without even the implied warranty of
  17   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  18   General Public License for more details.
  19
  20   You should have received a copy of the GNU Lesser General Public License
  21   along with PulseAudio; if not, write to the Free Software
  22   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  23   USA.
  24 ***/
  25
  26 #include <inttypes.h>
  27
  28 #include <pulse/cdecl.h>
  29 #include <pulse/gccmacro.h>
  30 #include <pulse/sample.h>
  31 #include <pulse/channelmap.h>
  32 #include <pulse/version.h>
  33
  34 /** \page volume Volume Control
  35  *
  36  * \section overv_sec Overview
  37  *
  38  * Sinks, sources, sink inputs and samples can all have their own volumes.
  39  * To deal with these, The PulseAudio libray contains a number of functions
  40  * that ease handling.
  41  *
  42  * The basic volume type in PulseAudio is the \ref pa_volume_t type. Most of
  43  * the time, applications will use the aggregated pa_cvolume structure that
  44  * can store the volume of all channels at once.
  45  *
  46  * Volumes commonly span between muted (0%), and normal (100%). It is possible
  47  * to set volumes to higher than 100%, but clipping might occur.
  48  *
  49  * \section calc_sec Calculations
  50  *
  51  * The volumes in PulseAudio are logarithmic in nature and applications
  52  * shouldn't perform calculations with them directly. Instead, they should
  53  * be converted to and from either dB or a linear scale:
  54  *
  55  * \li dB - pa_sw_volume_from_dB() / pa_sw_volume_to_dB()
  56  * \li Linear - pa_sw_volume_from_linear() / pa_sw_volume_to_linear()
  57  *
  58  * For simple multiplication, pa_sw_volume_multiply() and
  59  * pa_sw_cvolume_multiply() can be used.
  60  *
  61  * Calculations can only be reliably performed on software volumes
  62  * as it is commonly unknown what scale hardware volumes relate to.
  63  *
  64  * The functions described above are only valid when used with
  65  * software volumes. Hence it is usually a better idea to treat all
  66  * volume values as opaque with a range from PA_VOLUME_MUTED (0%) to
  67  * PA_VOLUME_NORM (100%) and to refrain from any calculations with
  68  * them.
  69  *
  70  * \section conv_sec Convenience Functions
  71  *
  72  * To handle the pa_cvolume structure, the PulseAudio library provides a
  73  * number of convenienc functions:
  74  *
  75  * \li pa_cvolume_valid() - Tests if a pa_cvolume structure is valid.
  76  * \li pa_cvolume_equal() - Tests if two pa_cvolume structures are identical.
  77  * \li pa_cvolume_channels_equal_to() - Tests if all channels of a pa_cvolume
  78  *                             structure have a given volume.
  79  * \li pa_cvolume_is_muted() - Tests if all channels of a pa_cvolume
  80  *                             structure are muted.
  81  * \li pa_cvolume_is_norm() - Tests if all channels of a pa_cvolume structure
  82  *                            are at a normal volume.
  83  * \li pa_cvolume_set() - Set all channels of a pa_cvolume structure to a
  84  *                        certain volume.
  85  * \li pa_cvolume_reset() - Set all channels of a pa_cvolume structure to a
  86  *                          normal volume.
  87  * \li pa_cvolume_mute() - Set all channels of a pa_cvolume structure to a
  88  *                         muted volume.
  89  * \li pa_cvolume_avg() - Return the average volume of all channels.
  90  * \li pa_cvolume_snprint() - Pretty print a pa_cvolume structure.
  91  */
  92
  93 /** \file
  94  * Constants and routines for volume handling */
  95
  96 PA_C_DECL_BEGIN
  97
  98 /** Volume specification:
  99  *  PA_VOLUME_MUTED: silence;
 100  * < PA_VOLUME_NORM: decreased volume;
 101  *   PA_VOLUME_NORM: normal volume;
 102  * > PA_VOLUME_NORM: increased volume */
 103 typedef uint32_t pa_volume_t;
 104
 105 /** Normal volume (100%) */
 106 #define PA_VOLUME_NORM ((pa_volume_t) 0x10000U)
 107
 108 /** Muted volume (0%) */
 109 #define PA_VOLUME_MUTED ((pa_volume_t) 0U)
 110
 111 /** A structure encapsulating a per-channel volume */
 112 typedef struct pa_cvolume {
 113     uint8_t channels;                     /**< Number of channels */
 114     pa_volume_t values[PA_CHANNELS_MAX];  /**< Per-channel volume  */
 115 } pa_cvolume;
 116
 117 /** Return non-zero when *a == *b */
 118 int pa_cvolume_equal(const pa_cvolume *a, const pa_cvolume *b) PA_GCC_PURE;
 119
 120 /** Initialize the specified volume and return a pointer to
 121  * it. The sample spec will have a defined state but
 122  * pa_cvolume_valid() will fail for it. \since 0.9.13 */
 123 pa_cvolume* pa_cvolume_init(pa_cvolume *a);
 124
 125 /** Set the volume of all channels to PA_VOLUME_NORM */
 126 #define pa_cvolume_reset(a, n) pa_cvolume_set((a), (n), PA_VOLUME_NORM)
 127
 128 /** Set the volume of all channels to PA_VOLUME_MUTED */
 129 #define pa_cvolume_mute(a, n) pa_cvolume_set((a), (n), PA_VOLUME_MUTED)
 130
 131 /** Set the volume of all channels to the specified parameter */
 132 pa_cvolume* pa_cvolume_set(pa_cvolume *a, unsigned channels, pa_volume_t v);
 133
 134 /** Maximum length of the strings returned by
 135  * pa_cvolume_snprint(). Please note that this value can change with
 136  * any release without warning and without being considered API or ABI
 137  * breakage. You should not use this definition anywhere where it
 138  * might become part of an ABI.*/
 139 #define PA_CVOLUME_SNPRINT_MAX 320
 140
 141 /** Pretty print a volume structure */
 142 char *pa_cvolume_snprint(char *s, size_t l, const pa_cvolume *c);
 143
 144 /** Maximum length of the strings returned by
 145  * pa_cvolume_snprint_dB(). Please note that this value can change with
 146  * any release without warning and without being considered API or ABI
 147  * breakage. You should not use this definition anywhere where it
 148  * might become part of an ABI. \since 0.9.13 */
 149 #define PA_SW_CVOLUME_SNPRINT_DB_MAX 448
 150
 151 /** Pretty print a volume structure but show dB values. \since 0.9.13 */
 152 char *pa_sw_cvolume_snprint_dB(char *s, size_t l, const pa_cvolume *c);
 153
 154 /** Maximum length of the strings returned by
 155  * pa_volume_snprint(). Please note that this value can change with
 156  * any release without warning and without being considered API or ABI
 157  * breakage. You should not use this definition anywhere where it
 158  * might become part of an ABI. \since 0.9.15 */
 159 #define PA_VOLUME_SNPRINT_MAX 10
 160
 161 /** Pretty print a volume \since 0.9.15 */
 162 char *pa_volume_snprint(char *s, size_t l, pa_volume_t v);
 163
 164 /** Maximum length of the strings returned by
 165  * pa_volume_snprint_dB(). Please note that this value can change with
 166  * any release without warning and without being considered API or ABI
 167  * breakage. You should not use this definition anywhere where it
 168  * might become part of an ABI. \since 0.9.15 */
 169 #define PA_SW_VOLUME_SNPRINT_DB_MAX 10
 170
 171 /** Pretty print a volume but show dB values. \since 0.9.15 */
 172 char *pa_sw_volume_snprint_dB(char *s, size_t l, pa_volume_t v);
 173
 174 /** Return the average volume of all channels */
 175 pa_volume_t pa_cvolume_avg(const pa_cvolume *a) PA_GCC_PURE;
 176
 177 /** Return the maximum volume of all channels. \since 0.9.12 */
 178 pa_volume_t pa_cvolume_max(const pa_cvolume *a) PA_GCC_PURE;
 179
 180 /** Return TRUE when the passed cvolume structure is valid, FALSE otherwise */
 181 int pa_cvolume_valid(const pa_cvolume *v) PA_GCC_PURE;
 182
 183 /** Return non-zero if the volume of all channels is equal to the specified value */
 184 int pa_cvolume_channels_equal_to(const pa_cvolume *a, pa_volume_t v) PA_GCC_PURE;
 185
 186 /** Return 1 if the specified volume has all channels muted */
 187 #define pa_cvolume_is_muted(a) pa_cvolume_channels_equal_to((a), PA_VOLUME_MUTED)
 188
 189 /** Return 1 if the specified volume has all channels on normal level */
 190 #define pa_cvolume_is_norm(a) pa_cvolume_channels_equal_to((a), PA_VOLUME_NORM)
 191
 192 /** Multiply two volume specifications, return the result. This uses
 193  * PA_VOLUME_NORM as neutral element of multiplication. This is only
 194  * valid for software volumes! */
 195 pa_volume_t pa_sw_volume_multiply(pa_volume_t a, pa_volume_t b) PA_GCC_CONST;
 196
 197 /** Multiply two per-channel volumes and return the result in
 198  * *dest. This is only valid for software volumes! */
 199 pa_cvolume *pa_sw_cvolume_multiply(pa_cvolume *dest, const pa_cvolume *a, const pa_cvolume *b);
 200
 201 /** Divide two volume specifications, return the result. This uses
 202  * PA_VOLUME_NORM as neutral element of division. This is only valid
 203  * for software volumes! If a division by zero is tried the result
 204  * will be 0. \since 0.9.13 */
 205 pa_volume_t pa_sw_volume_divide(pa_volume_t a, pa_volume_t b) PA_GCC_CONST;
 206
 207 /** Multiply to per-channel volumes and return the result in
 208  * *dest. This is only valid for software volumes! \since 0.9.13 */
 209 pa_cvolume *pa_sw_cvolume_divide(pa_cvolume *dest, const pa_cvolume *a, const pa_cvolume *b);
 210
 211 /** Convert a decibel value to a volume. This is only valid for software volumes! */
 212 pa_volume_t pa_sw_volume_from_dB(double f) PA_GCC_CONST;
 213
 214 /** Convert a volume to a decibel value. This is only valid for software volumes! */
 215 double pa_sw_volume_to_dB(pa_volume_t v) PA_GCC_CONST;
 216
 217 /** Convert a linear factor to a volume. This is only valid for software volumes! */
 218 pa_volume_t pa_sw_volume_from_linear(double v) PA_GCC_CONST;
 219
 220 /** Convert a volume to a linear factor. This is only valid for software volumes! */
 221 double pa_sw_volume_to_linear(pa_volume_t v) PA_GCC_CONST;
 222
 223 #ifdef INFINITY
 224 #define PA_DECIBEL_MININFTY ((double) -INFINITY)
 225 #else
 226 /** This value is used as minus infinity when using pa_volume_{to,from}_dB(). */
 227 #define PA_DECIBEL_MININFTY ((double) -200.0)
 228 #endif
 229
 230 /** Remap a volume from one channel mapping to a different channel mapping. \since 0.9.12 */
 231 pa_cvolume *pa_cvolume_remap(pa_cvolume *v, const pa_channel_map *from, const pa_channel_map *to);
 232
 233 /** Return non-zero if the specified volume is compatible with the
 234  * specified sample spec. \since 0.9.13 */
 235 int pa_cvolume_compatible(const pa_cvolume *v, const pa_sample_spec *ss) PA_GCC_PURE;
 236
 237 /** Return non-zero if the specified volume is compatible with the
 238  * specified sample spec. \since 0.9.15 */
 239 int pa_cvolume_compatible_with_channel_map(const pa_cvolume *v, const pa_channel_map *cm) PA_GCC_PURE;
 240
 241 /** Calculate a 'balance' value for the specified volume with the
 242  * specified channel map. The return value will range from -1.0f
 243  * (left) to +1.0f (right). If no balance value is applicable to this
 244  * channel map the return value will always be 0.0f. See
 245  * pa_channel_map_can_balance(). \since 0.9.15 */
 246 float pa_cvolume_get_balance(const pa_cvolume *v, const pa_channel_map *map) PA_GCC_PURE;
 247
 248 /** Adjust the 'balance' value for the specified volume with the
 249  * specified channel map. v will be modified in place and
 250  * returned. The balance is a value between -1.0f and +1.0f. This
 251  * operation might not be reversible! Also, after this call
 252  * pa_cvolume_get_balance() is not guaranteed to actually return the
 253  * requested balance value (e.g. when the input volume was zero anyway for
 254  * all channels). If no balance value is applicable to
 255  * this channel map the volume will not be modified. See
 256  * pa_channel_map_can_balance(). \since 0.9.15 */
 257 pa_cvolume* pa_cvolume_set_balance(pa_cvolume *v, const pa_channel_map *map, float new_balance);
 258
 259 /** Calculate a 'fade' value (i.e. 'balance' between front and rear)
 260  * for the specified volume with the specified channel map. The return
 261  * value will range from -1.0f (rear) to +1.0f (left). If no fade
 262  * value is applicable to this channel map the return value will
 263  * always be 0.0f. See pa_channel_map_can_fade(). \since 0.9.15 */
 264 float pa_cvolume_get_fade(const pa_cvolume *v, const pa_channel_map *map) PA_GCC_PURE;
 265
 266 /** Adjust the 'fade' value (i.e. 'balance' between front and rear)
 267  * for the specified volume with the specified channel map. v will be
 268  * modified in place and returned. The balance is a value between
 269  * -1.0f and +1.0f. This operation might not be reversible! Also,
 270  * after this call pa_cvolume_get_fade() is not guaranteed to actually
 271  * return the requested fade value (e.g. when the input volume was
 272  * zero anyway for all channels). If no fade value is applicable to
 273  * this channel map the volume will not be modified. See
 274  * pa_channel_map_can_fade(). \since 0.9.15 */
 275 pa_cvolume* pa_cvolume_set_fade(pa_cvolume *v, const pa_channel_map *map, float new_fade);
 276
 277 /** Scale the passed pa_cvolume structure so that the maximum volume
 278  * of all channels equals max. The proportions between the channel
 279  * volumes are kept. \since 0.9.15 */
 280 pa_cvolume* pa_cvolume_scale(pa_cvolume *v, pa_volume_t max);
 281
 282 PA_C_DECL_END
 283
 284 #endif