codecs/codec_resample.c

   1 /*
   2  * Asterisk -- An open source telephony toolkit.
   3  *
   4  * Copyright (C) 2007, Digium, Inc.
   5  *
   6  * Russell Bryant <russell@digium.com>
   7  *
   8  * See http://www.asterisk.org for more information about
   9  * the Asterisk project. Please do not directly contact
  10  * any of the maintainers of this project for assistance;
  11  * the project provides a web site, mailing lists and IRC
  12  * channels for your use.
  13  *
  14  * This program is free software, distributed under the terms of
  15  * the GNU General Public License Version 2. See the LICENSE file
  16  * at the top of the source tree.
  17  */
  18
  19 /*!
  20  * \file
  21  *
  22  * \brief Resample slinear audio
  23  *
  24  * \ingroup codecs
  25  */
  26
  27 #include "asterisk.h"
  28
  29 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
  30
  31 /* These are for SHRT_MAX and FLT_MAX -- { */
  32 #if defined(__Darwin__) || defined(__OpenBSD__) || defined(__FreeBSD__) || defined(__NetBSD__) || defined(__CYGWIN__)
  33 #include <float.h>
  34 #else
  35 #include <values.h>
  36 #endif
  37 #include <limits.h>
  38 /* } */
  39
  40 #include "asterisk/module.h"
  41 #include "asterisk/translate.h"
  42 #include "asterisk/libresample.h"
  43
  44 #include "slin_resample_ex.h"
  45
  46 #define RESAMPLER_QUALITY 0
  47
  48 #define OUTBUF_SIZE   8096
  49
  50 struct slin16_to_slin8_pvt {
  51         void *resampler;
  52         double resample_factor;
  53 };
  54
  55 struct slin8_to_slin16_pvt {
  56         void *resampler;
  57         double resample_factor;
  58 };
  59
  60 static int slin16_to_slin8_new(struct ast_trans_pvt *pvt)
  61 {
  62         struct slin16_to_slin8_pvt *resamp_pvt = pvt->pvt;
  63
  64         resamp_pvt->resample_factor = 0.5;
  65
  66         if (!(resamp_pvt->resampler = resample_open(RESAMPLER_QUALITY, 0.5, 0.5)))
  67                 return -1;
  68
  69         return 0;
  70 }
  71
  72 static int slin8_to_slin16_new(struct ast_trans_pvt *pvt)
  73 {
  74         struct slin8_to_slin16_pvt *resamp_pvt = pvt->pvt;
  75
  76         resamp_pvt->resample_factor = 2.0;
  77
  78         if (!(resamp_pvt->resampler = resample_open(RESAMPLER_QUALITY, 2.0, 2.0)))
  79                 return -1;
  80
  81         return 0;
  82 }
  83
  84 static void slin16_to_slin8_destroy(struct ast_trans_pvt *pvt)
  85 {
  86         struct slin16_to_slin8_pvt *resamp_pvt = pvt->pvt;
  87
  88         if (resamp_pvt->resampler)
  89                 resample_close(resamp_pvt->resampler);
  90 }
  91
  92 static void slin8_to_slin16_destroy(struct ast_trans_pvt *pvt)
  93 {
  94         struct slin8_to_slin16_pvt *resamp_pvt = pvt->pvt;
  95
  96         if (resamp_pvt->resampler)
  97                 resample_close(resamp_pvt->resampler);
  98 }
  99
 100 static int resample_frame(struct ast_trans_pvt *pvt,
 101         void *resampler, double resample_factor, struct ast_frame *f)
 102 {
 103         int total_in_buf_used = 0;
 104         int total_out_buf_used = 0;
 105         int16_t *in_buf = (int16_t *) f->data;
 106         int16_t *out_buf = (int16_t *) pvt->outbuf + pvt->samples;
 107         float in_buf_f[f->samples];
 108         float out_buf_f[2048];
 109         int res = 0;
 110         int i;
 111
 112         for (i = 0; i < f->samples; i++)
 113                 in_buf_f[i] = in_buf[i] * (FLT_MAX / SHRT_MAX);
 114
 115         while (total_in_buf_used < f->samples) {
 116                 int in_buf_used, out_buf_used;
 117
 118                 out_buf_used = resample_process(resampler, resample_factor,
 119                         &in_buf_f[total_in_buf_used], f->samples - total_in_buf_used,
 120                         0, &in_buf_used,
 121                         &out_buf_f[total_out_buf_used], ARRAY_LEN(out_buf_f) - total_out_buf_used);
 122
 123                 if (out_buf_used < 0)
 124                         break;
 125
 126                 total_out_buf_used += out_buf_used;
 127                 total_in_buf_used += in_buf_used;
 128
 129                 if (total_out_buf_used == ARRAY_LEN(out_buf_f)) {
 130                         ast_log(LOG_ERROR, "Output buffer filled ... need to increase its size\n");
 131                         res = -1;
 132                         break;
 133                 }
 134         }
 135
 136         for (i = 0; i < total_out_buf_used; i++)
 137                 out_buf[i] = out_buf_f[i] * (SHRT_MAX / FLT_MAX);
 138
 139         pvt->samples += total_out_buf_used;
 140         pvt->datalen += (total_out_buf_used * sizeof(int16_t));
 141
 142         return res;
 143 }
 144
 145 static int slin16_to_slin8_framein(struct ast_trans_pvt *pvt, struct ast_frame *f)
 146 {
 147         struct slin16_to_slin8_pvt *resamp_pvt = pvt->pvt;
 148
 149         return resample_frame(pvt, resamp_pvt->resampler, resamp_pvt->resample_factor, f);
 150 }
 151
 152 static int slin8_to_slin16_framein(struct ast_trans_pvt *pvt, struct ast_frame *f)
 153 {
 154         struct slin8_to_slin16_pvt *resamp_pvt = pvt->pvt;
 155
 156         return resample_frame(pvt, resamp_pvt->resampler, resamp_pvt->resample_factor, f);
 157 }
 158
 159 static struct ast_frame *slin16_to_slin8_sample(void)
 160 {
 161         static struct ast_frame f = {
 162                 .frametype = AST_FRAME_VOICE,
 163                 .subclass = AST_FORMAT_SLINEAR16,
 164                 .datalen = sizeof(slin16_slin8_ex),
 165                 .samples = sizeof(slin16_slin8_ex) / sizeof(slin16_slin8_ex[0]),
 166                 .src = __PRETTY_FUNCTION__,
 167                 .data = slin16_slin8_ex,
 168         };
 169
 170         return &f;
 171 }
 172
 173 static struct ast_frame *slin8_to_slin16_sample(void)
 174 {
 175         static struct ast_frame f = {
 176                 .frametype = AST_FRAME_VOICE,
 177                 .subclass = AST_FORMAT_SLINEAR,
 178                 .datalen = sizeof(slin8_slin16_ex),
 179                 .samples = sizeof(slin8_slin16_ex) / sizeof(slin8_slin16_ex[0]),
 180                 .src = __PRETTY_FUNCTION__,
 181                 .data = slin8_slin16_ex,
 182         };
 183
 184         return &f;
 185 }
 186
 187 static struct ast_translator slin16_to_slin8 = {
 188         .name = "slin16_to_slin8",
 189         .srcfmt = AST_FORMAT_SLINEAR16,
 190         .dstfmt = AST_FORMAT_SLINEAR,
 191         .newpvt = slin16_to_slin8_new,
 192         .destroy = slin16_to_slin8_destroy,
 193         .framein = slin16_to_slin8_framein,
 194         .sample = slin16_to_slin8_sample,
 195         .desc_size = sizeof(struct slin16_to_slin8_pvt),
 196         .buffer_samples = (OUTBUF_SIZE / sizeof(int16_t)),
 197         .buf_size = OUTBUF_SIZE,
 198 };
 199
 200 static struct ast_translator slin8_to_slin16 = {
 201         .name = "slin8_to_slin16",
 202         .srcfmt = AST_FORMAT_SLINEAR,
 203         .dstfmt = AST_FORMAT_SLINEAR16,
 204         .newpvt = slin8_to_slin16_new,
 205         .destroy = slin8_to_slin16_destroy,
 206         .framein = slin8_to_slin16_framein,
 207         .sample = slin8_to_slin16_sample,
 208         .desc_size = sizeof(struct slin8_to_slin16_pvt),
 209         .buffer_samples = OUTBUF_SIZE,
 210         .buf_size = OUTBUF_SIZE,
 211 };
 212
 213 static int unload_module(void)
 214 {
 215         int res = 0;
 216
 217         res |= ast_unregister_translator(&slin16_to_slin8);
 218         res |= ast_unregister_translator(&slin8_to_slin16);
 219
 220         return res;
 221 }
 222
 223 static int load_module(void)
 224 {
 225         int res = 0;
 226
 227         res |= ast_register_translator(&slin16_to_slin8);
 228         res |= ast_register_translator(&slin8_to_slin16);
 229
 230         return AST_MODULE_LOAD_SUCCESS;
 231 }
 232
 233 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "SLIN Resampling Codec");