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 typedef struct pa_cvolume {
  49     uint8_t channels;
  50     pa_volume_t values[PA_CHANNELS_MAX];
  51 } pa_cvolume;
  52
  53 /** Return non-zero when *a == *b */
  54 int pa_cvolume_equal(const pa_cvolume *a, const pa_cvolume *b);
  55
  56 /** Set the volume of all channels to PA_VOLUME_NORM */
  57 #define pa_cvolume_reset(a, n) pa_cvolume_set((a), (n), PA_VOLUME_NORM)
  58
  59 /** Set the volume of all channels to PA_VOLUME_MUTED */
  60 #define pa_cvolume_mute(a, n) pa_cvolume_set((a), (n), PA_VOLUME_MUTED)
  61
  62 /** Set the volume of all channels to the specified parameter */
  63 pa_cvolume* pa_cvolume_set(pa_cvolume *a, unsigned channels, pa_volume_t v);
  64
  65 /** Pretty print a volume structure */
  66 #define PA_CVOLUME_SNPRINT_MAX 64
  67 char *pa_cvolume_snprint(char *s, size_t l, const pa_cvolume *c);
  68
  69 /** Return the average volume of all channels */
  70 pa_volume_t pa_cvolume_avg(const pa_cvolume *a);
  71
  72 /** Return TRUE when the passed cvolume structure is valid, FALSE otherwise */
  73 int pa_cvolume_valid(const pa_cvolume *v);
  74
  75 /** Return non-zero if the volume of all channels is equal to the specified value */
  76 int pa_cvolume_channels_equal_to(const pa_cvolume *a, pa_volume_t v);
  77
  78 #define pa_cvolume_is_muted(a) pa_cvolume_channels_equal_to((a), PA_VOLUME_MUTED)
  79 #define pa_cvolume_is_norm(a) pa_cvolume_channels_equal_to((a), PA_VOLUME_NORM)
  80
  81 /** Multiply two volumes specifications, return the result. This uses PA_VOLUME_NORM as neutral element of multiplication. */
  82 pa_volume_t pa_sw_volume_multiply(pa_volume_t a, pa_volume_t b);
  83
  84 pa_cvolume *pa_sw_cvolume_multiply(pa_cvolume *dest, const pa_cvolume *a, const pa_cvolume *b);
  85
  86 /** Convert a decibel value to a volume. \since 0.4 */
  87 pa_volume_t pa_sw_volume_from_dB(double f);
  88
  89 /** Convert a volume to a decibel value.  \since 0.4 */
  90 double pa_sw_volume_to_dB(pa_volume_t v);
  91
  92 /** Convert a linear factor to a volume. \since 0.8 */
  93 pa_volume_t pa_sw_volume_from_linear(double v);
  94
  95 /** Convert a volume to a linear factor. \since 0.8 */
  96 double pa_sw_volume_to_linear(pa_volume_t v);
  97
  98 #ifdef INFINITY
  99 #define PA_DECIBEL_MININFTY (-INFINITY)
 100 #else
 101 /** This value is used as minus infinity when using pa_volume_{to,from}_dB(). \since 0.4 */
 102 #define PA_DECIBEL_MININFTY (-200)
 103 #endif
 104
 105 PA_C_DECL_END
 106
 107 #endif