code.delx.au - pulseaudio/blob - polyp/volume.h

   1 #ifndef foovolumehfoo
   2 #define foovolumehfoo
   3
   4 /* $Id$ */
   5
   6 /***
   7   This file is part of polypaudio.
   8
   9   polypaudio is free software; you can redistribute it and/or modify
  10   it under the terms of the GNU Lesser General Public License as published
  11   by the Free Software Foundation; either version 2 of the License,
  12   or (at your option) any later version.
  13
  14   polypaudio is distributed in the hope that it will be useful, but
  15   WITHOUT ANY WARRANTY; without even the implied warranty of
  16   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  17   General Public License for more details.
  18
  19   You should have received a copy of the GNU Lesser General Public License
  20   along with polypaudio; if not, write to the Free Software
  21   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  22   USA.
  23 ***/
  24
  25 #include <inttypes.h>
  26 #include <polyp/cdecl.h>
  27 #include <polyp/sample.h>
  28
  29 /** \file
  30  * Constants and routines for volume handling */
  31
  32 PA_C_DECL_BEGIN
  33
  34 /** Volume specification:
  35  *  PA_VOLUME_MUTED: silence;
  36  * < PA_VOLUME_NORM: decreased volume;
  37  *   PA_VOLUME_NORM: normal volume;
  38  * > PA_VOLUME_NORM: increased volume */
  39 typedef uint32_t pa_volume_t;
  40
  41 /** Normal volume (100%) */
  42 #define PA_VOLUME_NORM (0x10000)
  43
  44 /** Muted volume (0%) */
  45 #define PA_VOLUME_MUTED (0)
  46
  47 /** A structure encapsulating a per-channel volume */
  48 struct pa_cvolume {
  49     uint8_t channels;
  50     pa_volume_t values[PA_CHANNELS_MAX];
  51 };
  52
  53 /** Return non-zero when *a == *b */
  54 int pa_cvolume_equal(const struct pa_cvolume *a, const struct pa_cvolume *b);
  55
  56 /** Set the volume of all channels to PA_VOLUME_NORM */
  57 void pa_cvolume_reset(struct pa_cvolume *a);
  58
  59 /** Set the volume of all channels to PA_VOLUME_MUTED */
  60 void pa_cvolume_mute(struct pa_cvolume *a);
  61
  62 /** Set the volume of all channels to the specified parameter */
  63 void pa_cvolume_set(struct pa_cvolume *a, pa_volume_t v);
  64
  65 /** Pretty print a volume structure */
  66 char *pa_cvolume_snprintf(char *s, size_t l, const struct pa_cvolume *c, unsigned channels);
  67
  68 /** Return the average volume of all channels */
  69 pa_volume_t pa_cvolume_avg(const struct pa_cvolume *a);
  70
  71 /** Return non-zero if the volume of all channels is equal to the specified value */
  72 int pa_cvolume_channels_equal_to(const struct pa_cvolume *a, uint8_t channels, pa_volume_t v);
  73
  74 /** Multiply two volumes specifications, return the result. This uses PA_VOLUME_NORM as neutral element of multiplication. */
  75 pa_volume_t pa_sw_volume_multiply(pa_volume_t a, pa_volume_t b);
  76
  77 /** Convert a decibel value to a volume. \since 0.4 */
  78 pa_volume_t pa_sw_volume_from_dB(double f);
  79
  80 /** Convert a volume to a decibel value.  \since 0.4 */
  81 double pa_sw_volume_to_dB(pa_volume_t v);
  82
  83 /** Convert a linear factor to a volume. \since 0.8 */
  84 pa_volume_t pa_sw_volume_from_linear(double v);
  85
  86 /** Convert a volume to a linear factor. \since 0.8 */
  87 double pa_sw_volume_to_linear(pa_volume_t v);
  88
  89 #ifdef INFINITY
  90 #define PA_DECIBEL_MININFTY (-INFINITY)
  91 #else
  92 /** This value is used as minus infinity when using pa_volume_{to,from}_dB(). \since 0.4 */
  93 #define PA_DECIBEL_MININFTY (-200)
  94 #endif
  95
  96 PA_C_DECL_END
  97
  98 #endif