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 /*** MODULEINFO
  28         <depend>res_resample</depend>
  29  ***/
  30
  31 #include "asterisk.h"
  32
  33 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
  34
  35 /* These are for SHRT_MAX and FLT_MAX -- { */
  36 #if defined(__Darwin__) || defined(__OpenBSD__) || defined(__FreeBSD__) || defined(__NetBSD__) || defined(__CYGWIN__)
  37 #include <float.h>
  38 #else
  39 #include <values.h>
  40 #endif
  41 #include <limits.h>
  42 /* } */
  43
  44 #include "asterisk/module.h"
  45 #include "asterisk/translate.h"
  46
  47 #include "libresample.h"
  48
  49 #include "slin_resample_ex.h"
  50
  51 #define RESAMPLER_QUALITY 0
  52
  53 #define OUTBUF_SIZE   8096
  54
  55 struct slin16_to_slin8_pvt {
  56         void *resampler;
  57         double resample_factor;
  58 };
  59
  60 struct slin8_to_slin16_pvt {
  61         void *resampler;
  62         double resample_factor;
  63 };
  64
  65 static int slin16_to_slin8_new(struct ast_trans_pvt *pvt)
  66 {
  67         struct slin16_to_slin8_pvt *resamp_pvt = pvt->pvt;
  68
  69         resamp_pvt->resample_factor = 0.5;
  70
  71         if (!(resamp_pvt->resampler = resample_open(RESAMPLER_QUALITY, 0.5, 0.5)))
  72                 return -1;
  73
  74         return 0;
  75 }
  76
  77 static int slin8_to_slin16_new(struct ast_trans_pvt *pvt)
  78 {
  79         struct slin8_to_slin16_pvt *resamp_pvt = pvt->pvt;
  80
  81         resamp_pvt->resample_factor = 2.0;
  82
  83         if (!(resamp_pvt->resampler = resample_open(RESAMPLER_QUALITY, 2.0, 2.0)))
  84                 return -1;
  85
  86         return 0;
  87 }
  88
  89 static void slin16_to_slin8_destroy(struct ast_trans_pvt *pvt)
  90 {
  91         struct slin16_to_slin8_pvt *resamp_pvt = pvt->pvt;
  92
  93         if (resamp_pvt->resampler)
  94                 resample_close(resamp_pvt->resampler);
  95 }
  96
  97 static void slin8_to_slin16_destroy(struct ast_trans_pvt *pvt)
  98 {
  99         struct slin8_to_slin16_pvt *resamp_pvt = pvt->pvt;
 100
 101         if (resamp_pvt->resampler)
 102                 resample_close(resamp_pvt->resampler);
 103 }
 104
 105 static int resample_frame(struct ast_trans_pvt *pvt,
 106         void *resampler, double resample_factor, struct ast_frame *f)
 107 {
 108         int total_in_buf_used = 0;
 109         int total_out_buf_used = 0;
 110         int16_t *in_buf = (int16_t *) f->data;
 111         int16_t *out_buf = (int16_t *) pvt->outbuf + pvt->samples;
 112         float in_buf_f[f->samples];
 113         float out_buf_f[2048];
 114         int res = 0;
 115         int i;
 116
 117         for (i = 0; i < f->samples; i++)
 118                 in_buf_f[i] = in_buf[i] * (FLT_MAX / SHRT_MAX);
 119
 120         while (total_in_buf_used < f->samples) {
 121                 int in_buf_used, out_buf_used;
 122
 123                 out_buf_used = resample_process(resampler, resample_factor,
 124                         &in_buf_f[total_in_buf_used], f->samples - total_in_buf_used,
 125                         0, &in_buf_used,
 126                         &out_buf_f[total_out_buf_used], ARRAY_LEN(out_buf_f) - total_out_buf_used);
 127
 128                 if (out_buf_used < 0)
 129                         break;
 130
 131                 total_out_buf_used += out_buf_used;
 132                 total_in_buf_used += in_buf_used;
 133
 134                 if (total_out_buf_used == ARRAY_LEN(out_buf_f)) {
 135                         ast_log(LOG_ERROR, "Output buffer filled ... need to increase its size\n");
 136                         res = -1;
 137                         break;
 138                 }
 139         }
 140
 141         for (i = 0; i < total_out_buf_used; i++)
 142                 out_buf[i] = out_buf_f[i] * (SHRT_MAX / FLT_MAX);
 143
 144         pvt->samples += total_out_buf_used;
 145         pvt->datalen += (total_out_buf_used * sizeof(int16_t));
 146
 147         return res;
 148 }
 149
 150 static int slin16_to_slin8_framein(struct ast_trans_pvt *pvt, struct ast_frame *f)
 151 {
 152         struct slin16_to_slin8_pvt *resamp_pvt = pvt->pvt;
 153
 154         return resample_frame(pvt, resamp_pvt->resampler, resamp_pvt->resample_factor, f);
 155 }
 156
 157 static int slin8_to_slin16_framein(struct ast_trans_pvt *pvt, struct ast_frame *f)
 158 {
 159         struct slin8_to_slin16_pvt *resamp_pvt = pvt->pvt;
 160
 161         return resample_frame(pvt, resamp_pvt->resampler, resamp_pvt->resample_factor, f);
 162 }
 163
 164 static struct ast_frame *slin16_to_slin8_sample(void)
 165 {
 166         static struct ast_frame f = {
 167                 .frametype = AST_FRAME_VOICE,
 168                 .subclass = AST_FORMAT_SLINEAR16,
 169                 .datalen = sizeof(slin16_slin8_ex),
 170                 .samples = sizeof(slin16_slin8_ex) / sizeof(slin16_slin8_ex[0]),
 171                 .src = __PRETTY_FUNCTION__,
 172                 .data = slin16_slin8_ex,
 173         };
 174
 175         return &f;
 176 }
 177
 178 static struct ast_frame *slin8_to_slin16_sample(void)
 179 {
 180         static struct ast_frame f = {
 181                 .frametype = AST_FRAME_VOICE,
 182                 .subclass = AST_FORMAT_SLINEAR,
 183                 .datalen = sizeof(slin8_slin16_ex),
 184                 .samples = sizeof(slin8_slin16_ex) / sizeof(slin8_slin16_ex[0]),
 185                 .src = __PRETTY_FUNCTION__,
 186                 .data = slin8_slin16_ex,
 187         };
 188
 189         return &f;
 190 }
 191
 192 static struct ast_translator slin16_to_slin8 = {
 193         .name = "slin16_to_slin8",
 194         .srcfmt = AST_FORMAT_SLINEAR16,
 195         .dstfmt = AST_FORMAT_SLINEAR,
 196         .newpvt = slin16_to_slin8_new,
 197         .destroy = slin16_to_slin8_destroy,
 198         .framein = slin16_to_slin8_framein,
 199         .sample = slin16_to_slin8_sample,
 200         .desc_size = sizeof(struct slin16_to_slin8_pvt),
 201         .buffer_samples = (OUTBUF_SIZE / sizeof(int16_t)),
 202         .buf_size = OUTBUF_SIZE,
 203 };
 204
 205 static struct ast_translator slin8_to_slin16 = {
 206         .name = "slin8_to_slin16",
 207         .srcfmt = AST_FORMAT_SLINEAR,
 208         .dstfmt = AST_FORMAT_SLINEAR16,
 209         .newpvt = slin8_to_slin16_new,
 210         .destroy = slin8_to_slin16_destroy,
 211         .framein = slin8_to_slin16_framein,
 212         .sample = slin8_to_slin16_sample,
 213         .desc_size = sizeof(struct slin8_to_slin16_pvt),
 214         .buffer_samples = OUTBUF_SIZE,
 215         .buf_size = OUTBUF_SIZE,
 216 };
 217
 218 static int unload_module(void)
 219 {
 220         int res = 0;
 221
 222         res |= ast_unregister_translator(&slin16_to_slin8);
 223         res |= ast_unregister_translator(&slin8_to_slin16);
 224
 225         return res;
 226 }
 227
 228 static int load_module(void)
 229 {
 230         int res = 0;
 231
 232         res |= ast_register_translator(&slin16_to_slin8);
 233         res |= ast_register_translator(&slin8_to_slin16);
 234
 235         return AST_MODULE_LOAD_SUCCESS;
 236 }
 237
 238 AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "SLIN Resampling Codec");