modules/audio_mixer/integer.c

   1 /*****************************************************************************
   2  * integer.c: integer software volume
   3  *****************************************************************************
   4  * Copyright (C) 2011 Rémi Denis-Courmont
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU Lesser General Public License as published by
   8  * the Free Software Foundation; either version 2.1 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public License
  17  * along with this program; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  19  *****************************************************************************/
  20
  21 #ifdef HAVE_CONFIG_H
  22 # include "config.h"
  23 #endif
  24
  25 #include <math.h>
  26 #include <limits.h>
  27
  28 #include <vlc_common.h>
  29 #include <vlc_plugin.h>
  30 #include <vlc_aout.h>
  31 #include <vlc_aout_volume.h>
  32
  33 static int Activate (vlc_object_t *);
  34
  35 vlc_module_begin ()
  36     set_category (CAT_AUDIO)
  37     set_subcategory (SUBCAT_AUDIO_MISC)
  38     set_description (N_("Integer audio volume"))
  39     set_capability ("audio volume", 9)
  40     set_callbacks (Activate, NULL)
  41 vlc_module_end ()
  42
  43 static void FilterS32N (audio_volume_t *vol, block_t *block, float volume)
  44 {
  45     int32_t *p = (int32_t *)block->p_buffer;
  46
  47     int_fast32_t mult = lroundf (volume * 0x1.p24f);
  48     if (mult == (1 << 24))
  49         return;
  50
  51     for (size_t n = block->i_buffer / sizeof (*p); n > 0; n--)
  52     {
  53         int_fast64_t s = (*p * (int_fast64_t)mult) >> INT64_C(24);
  54         if (s > INT32_MAX)
  55             s = INT32_MAX;
  56         else
  57         if (s < INT32_MIN)
  58             s = INT32_MIN;
  59         *(p++) = s;
  60     }
  61     (void) vol;
  62 }
  63
  64 static void FilterS16N (audio_volume_t *vol, block_t *block, float volume)
  65 {
  66     int16_t *p = (int16_t *)block->p_buffer;
  67
  68     int_fast16_t mult = lroundf (volume * 0x1.p8f);
  69     if (mult == (1 << 8))
  70         return;
  71
  72     for (size_t n = block->i_buffer / sizeof (*p); n > 0; n--)
  73     {
  74         int_fast32_t s = (*p * (int_fast32_t)mult) >> 8;
  75         if (s > INT16_MAX)
  76             s = INT16_MAX;
  77         else
  78         if (s < INT16_MIN)
  79             s = INT16_MIN;
  80         *(p++) = s;
  81     }
  82     (void) vol;
  83 }
  84
  85 static void FilterU8 (audio_volume_t *vol, block_t *block, float volume)
  86 {
  87     uint8_t *p = (uint8_t *)block->p_buffer;
  88
  89     int_fast16_t mult = lroundf (volume * 0x1.p8f);
  90     if (mult == (1 << 8))
  91         return;
  92
  93     for (size_t n = block->i_buffer / sizeof (*p); n > 0; n--)
  94     {
  95         int_fast32_t s = (((int_fast8_t)(*p - 128)) * (int_fast32_t)mult) >> 8;
  96         if (s > INT8_MAX)
  97             s = INT8_MAX;
  98         else
  99         if (s < INT8_MIN)
 100             s = INT8_MIN;
 101         *(p++) = s + 128;
 102     }
 103     (void) vol;
 104 }
 105
 106 static int Activate (vlc_object_t *obj)
 107 {
 108     audio_volume_t *vol = (audio_volume_t *)obj;
 109
 110     switch (vol->format)
 111     {
 112         case VLC_CODEC_S32N:
 113             vol->amplify = FilterS32N;
 114             break;
 115         case VLC_CODEC_S16N:
 116             vol->amplify = FilterS16N;
 117             break;
 118         case VLC_CODEC_U8:
 119             vol->amplify = FilterU8;
 120             break;
 121         default:
 122             return -1;
 123     }
 124     return 0;
 125 }