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

   1 /* $Id$ */
   2
   3 /***
   4   This file is part of PulseAudio.
   5
   6   Copyright 2004-2006 Lennart Poettering
   7
   8   PulseAudio is free software; you can redistribute it and/or modify
   9   it under the terms of the GNU Lesser General Public License as published
  10   by the Free Software Foundation; either version 2 of the License,
  11   or (at your option) any later version.
  12
  13   PulseAudio is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with PulseAudio; if not, write to the Free Software
  20   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  21   USA.
  22 ***/
  23
  24 #ifdef HAVE_CONFIG_H
  25 #include <config.h>
  26 #endif
  27
  28 #include <assert.h>
  29 #include <stdio.h>
  30 #include <string.h>
  31
  32 #include "volume.h"
  33
  34 int pa_cvolume_equal(const pa_cvolume *a, const pa_cvolume *b) {
  35     int i;
  36     assert(a);
  37     assert(b);
  38
  39     if (a->channels != b->channels)
  40         return 0;
  41
  42     for (i = 0; i < a->channels; i++)
  43         if (a->values[i] != b->values[i])
  44             return 0;
  45
  46     return 1;
  47 }
  48
  49 pa_cvolume* pa_cvolume_set(pa_cvolume *a, unsigned channels, pa_volume_t v) {
  50     int i;
  51
  52     assert(a);
  53     assert(channels > 0);
  54     assert(channels <= PA_CHANNELS_MAX);
  55
  56     a->channels = channels;
  57
  58     for (i = 0; i < a->channels; i++)
  59         a->values[i] = v;
  60
  61     return a;
  62 }
  63
  64 pa_volume_t pa_cvolume_avg(const pa_cvolume *a) {
  65     uint64_t sum = 0;
  66     int i;
  67     assert(a);
  68
  69     for (i = 0; i < a->channels; i++)
  70         sum += a->values[i];
  71
  72     sum /= a->channels;
  73
  74     return (pa_volume_t) sum;
  75 }
  76
  77 pa_volume_t pa_sw_volume_multiply(pa_volume_t a, pa_volume_t b) {
  78     return pa_sw_volume_from_linear(pa_sw_volume_to_linear(a)* pa_sw_volume_to_linear(b));
  79 }
  80
  81 #define USER_DECIBEL_RANGE 30
  82
  83 pa_volume_t pa_sw_volume_from_dB(double dB) {
  84     if (dB <= -USER_DECIBEL_RANGE)
  85         return PA_VOLUME_MUTED;
  86
  87     return (pa_volume_t) ((dB/USER_DECIBEL_RANGE+1)*PA_VOLUME_NORM);
  88 }
  89
  90 double pa_sw_volume_to_dB(pa_volume_t v) {
  91     if (v == PA_VOLUME_MUTED)
  92         return PA_DECIBEL_MININFTY;
  93
  94     return ((double) v/PA_VOLUME_NORM-1)*USER_DECIBEL_RANGE;
  95 }
  96
  97 pa_volume_t pa_sw_volume_from_linear(double v) {
  98
  99     if (v <= 0)
 100         return PA_VOLUME_MUTED;
 101
 102     if (v > .999 && v < 1.001)
 103         return PA_VOLUME_NORM;
 104
 105     return pa_sw_volume_from_dB(20*log10(v));
 106 }
 107
 108 double pa_sw_volume_to_linear(pa_volume_t v) {
 109
 110     if (v == PA_VOLUME_MUTED)
 111         return 0;
 112
 113     return pow(10, pa_sw_volume_to_dB(v)/20);
 114 }
 115
 116 char *pa_cvolume_snprint(char *s, size_t l, const pa_cvolume *c) {
 117     unsigned channel;
 118     int first = 1;
 119     char *e;
 120
 121     assert(s);
 122     assert(l > 0);
 123     assert(c);
 124
 125     *(e = s) = 0;
 126
 127     for (channel = 0; channel < c->channels && l > 1; channel++) {
 128         l -= snprintf(e, l, "%s%u: %3u%%",
 129                       first ? "" : " ",
 130                       channel,
 131                       (c->values[channel]*100)/PA_VOLUME_NORM);
 132
 133         e = strchr(e, 0);
 134         first = 0;
 135     }
 136
 137     return s;
 138 }
 139
 140 /** Return non-zero if the volume of all channels is equal to the specified value */
 141 int pa_cvolume_channels_equal_to(const pa_cvolume *a, pa_volume_t v) {
 142     unsigned c;
 143     assert(a);
 144
 145     for (c = 0; c < a->channels; c++)
 146         if (a->values[c] != v)
 147             return 0;
 148
 149     return 1;
 150 }
 151
 152 pa_cvolume *pa_sw_cvolume_multiply(pa_cvolume *dest, const pa_cvolume *a, const pa_cvolume *b) {
 153     unsigned i;
 154
 155     assert(dest);
 156     assert(a);
 157     assert(b);
 158
 159     for (i = 0; i < a->channels && i < b->channels && i < PA_CHANNELS_MAX; i++) {
 160
 161         dest->values[i] = pa_sw_volume_multiply(
 162             i < a->channels ? a->values[i] : PA_VOLUME_NORM,
 163             i < b->channels ? b->values[i] : PA_VOLUME_NORM);
 164     }
 165
 166     dest->channels = i;
 167
 168     return dest;
 169 }
 170
 171 int pa_cvolume_valid(const pa_cvolume *v) {
 172     assert(v);
 173
 174     if (v->channels <= 0 || v->channels > PA_CHANNELS_MAX)
 175         return 0;
 176
 177     return 1;
 178 }