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