code.delx.au - pulseaudio/blob - polyp/sample.c

   1 /* $Id$ */
   2
   3 /***
   4   This file is part of polypaudio.
   5
   6   polypaudio is free software; you can redistribute it and/or modify
   7   it under the terms of the GNU General Public License as published
   8   by the Free Software Foundation; either version 2 of the License,
   9   or (at your option) any later version.
  10
  11   polypaudio is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   General Public License for more details.
  15
  16   You should have received a copy of the GNU General Public License
  17   along with polypaudio; if not, write to the Free Software
  18   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  19   USA.
  20 ***/
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include <config.h>
  24 #endif
  25
  26 #include <stdio.h>
  27 #include <assert.h>
  28 #include <math.h>
  29
  30 #include "sample.h"
  31
  32 size_t pa_frame_size(const struct pa_sample_spec *spec) {
  33     size_t b = 1;
  34     assert(spec);
  35
  36     switch (spec->format) {
  37         case PA_SAMPLE_U8:
  38         case PA_SAMPLE_ULAW:
  39         case PA_SAMPLE_ALAW:
  40             b = 1;
  41             break;
  42         case PA_SAMPLE_S16LE:
  43         case PA_SAMPLE_S16BE:
  44             b = 2;
  45             break;
  46         case PA_SAMPLE_FLOAT32LE:
  47         case PA_SAMPLE_FLOAT32BE:
  48             b = 4;
  49             break;
  50         default:
  51             assert(0);
  52     }
  53
  54     return b * spec->channels;
  55 }
  56
  57 size_t pa_bytes_per_second(const struct pa_sample_spec *spec) {
  58     assert(spec);
  59     return spec->rate*pa_frame_size(spec);
  60 }
  61
  62 uint32_t pa_bytes_to_usec(size_t length, const struct pa_sample_spec *spec) {
  63     assert(spec);
  64
  65     return (uint32_t) (((double) length/pa_frame_size(spec)*1000000)/spec->rate);
  66 }
  67
  68 int pa_sample_spec_valid(const struct pa_sample_spec *spec) {
  69     assert(spec);
  70
  71     if (!spec->rate || !spec->channels)
  72         return 0;
  73
  74     if (spec->format >= PA_SAMPLE_MAX)
  75         return 0;
  76
  77     return 1;
  78 }
  79
  80 int pa_sample_spec_equal(const struct pa_sample_spec*a, const struct pa_sample_spec*b) {
  81     assert(a && b);
  82
  83     return (a->format == b->format) && (a->rate == b->rate) && (a->channels == b->channels);
  84 }
  85
  86 void pa_sample_spec_snprint(char *s, size_t l, const struct pa_sample_spec *spec) {
  87     static const char* const table[]= {
  88         [PA_SAMPLE_U8] = "U8",
  89         [PA_SAMPLE_ALAW] = "ALAW",
  90         [PA_SAMPLE_ULAW] = "ULAW",
  91         [PA_SAMPLE_S16LE] = "S16LE",
  92         [PA_SAMPLE_S16BE] = "S16BE",
  93         [PA_SAMPLE_FLOAT32LE] = "FLOAT32LE",
  94         [PA_SAMPLE_FLOAT32BE] = "FLOAT32BE",
  95     };
  96
  97     assert(pa_sample_spec_valid(spec));
  98     snprintf(s, l, "%s %uch %uHz", table[spec->format], spec->channels, spec->rate);
  99 }
 100
 101 pa_volume_t pa_volume_multiply(pa_volume_t a, pa_volume_t b) {
 102     uint64_t p = a;
 103     p *= b;
 104     p /= PA_VOLUME_NORM;
 105
 106     return (pa_volume_t) p;
 107 }
 108
 109 pa_volume_t pa_volume_from_dB(double f) {
 110     if (f <= PA_DECIBEL_MININFTY)
 111         return PA_VOLUME_MUTED;
 112
 113     return (pa_volume_t) (pow(10, f/20)*PA_VOLUME_NORM);
 114 }
 115
 116 double pa_volume_to_dB(pa_volume_t v) {
 117     if (v == PA_VOLUME_MUTED)
 118         return PA_DECIBEL_MININFTY;
 119
 120     return 20*log10((double) v/PA_VOLUME_NORM);
 121 }