src/pcm_resample_fallback.c

   1 /*
   2  * Copyright (C) 2003-2010 The Music Player Daemon Project
   3  * http://www.musicpd.org
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #include "config.h"
  21 #include "pcm_resample_internal.h"
  22
  23 #include <assert.h>
  24
  25 void
  26 pcm_resample_fallback_deinit(struct pcm_resample_state *state)
  27 {
  28         pcm_buffer_deinit(&state->buffer);
  29 }
  30
  31 /* resampling code blatantly ripped from ESD */
  32 const int16_t *
  33 pcm_resample_fallback_16(struct pcm_resample_state *state,
  34                          uint8_t channels,
  35                          unsigned src_rate,
  36                          const int16_t *src_buffer, size_t src_size,
  37                          unsigned dest_rate,
  38                          size_t *dest_size_r)
  39 {
  40         unsigned src_pos, dest_pos = 0;
  41         unsigned src_frames = src_size / channels / sizeof(*src_buffer);
  42         unsigned dest_frames =
  43                 (src_frames * dest_rate + src_rate - 1) / src_rate;
  44         unsigned dest_samples = dest_frames * channels;
  45         size_t dest_size = dest_samples * sizeof(*src_buffer);
  46         int16_t *dest_buffer = pcm_buffer_get(&state->buffer, dest_size);
  47
  48         assert((src_size % (sizeof(*src_buffer) * channels)) == 0);
  49
  50         switch (channels) {
  51         case 1:
  52                 while (dest_pos < dest_samples) {
  53                         src_pos = dest_pos * src_rate / dest_rate;
  54
  55                         dest_buffer[dest_pos++] = src_buffer[src_pos];
  56                 }
  57                 break;
  58         case 2:
  59                 while (dest_pos < dest_samples) {
  60                         src_pos = dest_pos * src_rate / dest_rate;
  61                         src_pos &= ~1;
  62
  63                         dest_buffer[dest_pos++] = src_buffer[src_pos];
  64                         dest_buffer[dest_pos++] = src_buffer[src_pos + 1];
  65                 }
  66                 break;
  67         }
  68
  69         *dest_size_r = dest_size;
  70         return dest_buffer;
  71 }
  72
  73 const int32_t *
  74 pcm_resample_fallback_32(struct pcm_resample_state *state,
  75                          uint8_t channels,
  76                          unsigned src_rate,
  77                          const int32_t *src_buffer, size_t src_size,
  78                          unsigned dest_rate,
  79                          size_t *dest_size_r)
  80 {
  81         unsigned src_pos, dest_pos = 0;
  82         unsigned src_frames = src_size / channels / sizeof(*src_buffer);
  83         unsigned dest_frames =
  84                 (src_frames * dest_rate + src_rate - 1) / src_rate;
  85         unsigned dest_samples = dest_frames * channels;
  86         size_t dest_size = dest_samples * sizeof(*src_buffer);
  87         int32_t *dest_buffer = pcm_buffer_get(&state->buffer, dest_size);
  88
  89         assert((src_size % (sizeof(*src_buffer) * channels)) == 0);
  90
  91         switch (channels) {
  92         case 1:
  93                 while (dest_pos < dest_samples) {
  94                         src_pos = dest_pos * src_rate / dest_rate;
  95
  96                         dest_buffer[dest_pos++] = src_buffer[src_pos];
  97                 }
  98                 break;
  99         case 2:
 100                 while (dest_pos < dest_samples) {
 101                         src_pos = dest_pos * src_rate / dest_rate;
 102                         src_pos &= ~1;
 103
 104                         dest_buffer[dest_pos++] = src_buffer[src_pos];
 105                         dest_buffer[dest_pos++] = src_buffer[src_pos + 1];
 106                 }
 107                 break;
 108         }
 109
 110         *dest_size_r = dest_size;
 111         return dest_buffer;
 112 }