codecs/codec_gsm.c

   1 /*
   2  * Asterisk -- An open source telephony toolkit.
   3  *
   4  * The GSM code is from TOAST.  Copyright information for that package is available
   5  * in the GSM directory.
   6  *
   7  * Copyright (C) 1999 - 2005, Digium, Inc.
   8  *
   9  * Mark Spencer <markster@digium.com>
  10  *
  11  * See http://www.asterisk.org for more information about
  12  * the Asterisk project. Please do not directly contact
  13  * any of the maintainers of this project for assistance;
  14  * the project provides a web site, mailing lists and IRC
  15  * channels for your use.
  16  *
  17  * This program is free software, distributed under the terms of
  18  * the GNU General Public License Version 2. See the LICENSE file
  19  * at the top of the source tree.
  20  */
  21
  22 /*! \file
  23  *
  24  * \brief Translate between signed linear and Global System for Mobile Communications (GSM)
  25  *
  26  * \ingroup codecs
  27  */
  28
  29 /*** MODULEINFO
  30         <depend>gsm</depend>
  31  ***/
  32
  33 #include "asterisk.h"
  34
  35 ASTERISK_FILE_VERSION(__FILE__, "$Revision$")
  36
  37 #include <fcntl.h>
  38 #include <stdlib.h>
  39 #include <unistd.h>
  40 #include <netinet/in.h>
  41 #include <string.h>
  42 #include <stdio.h>
  43
  44 #include "asterisk/lock.h"
  45 #include "asterisk/translate.h"
  46 #include "asterisk/config.h"
  47 #include "asterisk/options.h"
  48 #include "asterisk/module.h"
  49 #include "asterisk/logger.h"
  50 #include "asterisk/channel.h"
  51 #include "asterisk/utils.h"
  52
  53 #ifdef HAVE_GSM_HEADER
  54 #include "gsm.h"
  55 #elif defined(HAVE_GSM_GSM_HEADER)
  56 #include <gsm/gsm.h>
  57 #endif
  58
  59 #include "../formats/msgsm.h"
  60
  61 /* Sample frame data */
  62 #include "slin_gsm_ex.h"
  63 #include "gsm_slin_ex.h"
  64
  65 #define BUFFER_SAMPLES  8000
  66 #define GSM_SAMPLES     160
  67 #define GSM_FRAME_LEN   33
  68 #define MSGSM_FRAME_LEN 65
  69
  70 struct gsm_translator_pvt {     /* both gsm2lin and lin2gsm */
  71         gsm gsm;
  72         int16_t buf[BUFFER_SAMPLES];    /* lin2gsm, temporary storage */
  73 };
  74
  75 static int gsm_new(struct ast_trans_pvt *pvt)
  76 {
  77         struct gsm_translator_pvt *tmp = pvt->pvt;
  78
  79         return (tmp->gsm = gsm_create()) ? 0 : -1;
  80 }
  81
  82 static struct ast_frame *lintogsm_sample(void)
  83 {
  84         static struct ast_frame f;
  85         f.frametype = AST_FRAME_VOICE;
  86         f.subclass = AST_FORMAT_SLINEAR;
  87         f.datalen = sizeof(slin_gsm_ex);
  88         /* Assume 8000 Hz */
  89         f.samples = sizeof(slin_gsm_ex)/2;
  90         f.mallocd = 0;
  91         f.offset = 0;
  92         f.src = __PRETTY_FUNCTION__;
  93         f.data = slin_gsm_ex;
  94         return &f;
  95 }
  96
  97 static struct ast_frame *gsmtolin_sample(void)
  98 {
  99         static struct ast_frame f;
 100         f.frametype = AST_FRAME_VOICE;
 101         f.subclass = AST_FORMAT_GSM;
 102         f.datalen = sizeof(gsm_slin_ex);
 103         /* All frames are 20 ms long */
 104         f.samples = GSM_SAMPLES;
 105         f.mallocd = 0;
 106         f.offset = 0;
 107         f.src = __PRETTY_FUNCTION__;
 108         f.data = gsm_slin_ex;
 109         return &f;
 110 }
 111
 112 /*! \brief decode and store in outbuf. */
 113 static int gsmtolin_framein(struct ast_trans_pvt *pvt, struct ast_frame *f)
 114 {
 115         struct gsm_translator_pvt *tmp = pvt->pvt;
 116         int x;
 117         int16_t *dst = (int16_t *)pvt->outbuf;
 118         /* guess format from frame len. 65 for MSGSM, 33 for regular GSM */
 119         int flen = (f->datalen % MSGSM_FRAME_LEN == 0) ?
 120                 MSGSM_FRAME_LEN : GSM_FRAME_LEN;
 121
 122         for (x=0; x < f->datalen; x += flen) {
 123                 unsigned char data[2 * GSM_FRAME_LEN];
 124                 unsigned char *src;
 125                 int len;
 126                 if (flen == MSGSM_FRAME_LEN) {
 127                         len = 2*GSM_SAMPLES;
 128                         src = data;
 129                         /* Translate MSGSM format to Real GSM format before feeding in */
 130                         /* XXX what's the point here! we should just work
 131                          * on the full format.
 132                          */
 133                         conv65(f->data + x, data);
 134                 } else {
 135                         len = GSM_SAMPLES;
 136                         src = f->data + x;
 137                 }
 138                 /* XXX maybe we don't need to check */
 139                 if (pvt->samples + len > BUFFER_SAMPLES) {
 140                         ast_log(LOG_WARNING, "Out of buffer space\n");
 141                         return -1;
 142                 }
 143                 if (gsm_decode(tmp->gsm, src, dst + pvt->samples)) {
 144                         ast_log(LOG_WARNING, "Invalid GSM data (1)\n");
 145                         return -1;
 146                 }
 147                 pvt->samples += GSM_SAMPLES;
 148                 pvt->datalen += 2 * GSM_SAMPLES;
 149                 if (flen == MSGSM_FRAME_LEN) {
 150                         if (gsm_decode(tmp->gsm, data + GSM_FRAME_LEN, dst + pvt->samples)) {
 151                                 ast_log(LOG_WARNING, "Invalid GSM data (2)\n");
 152                                 return -1;
 153                         }
 154                         pvt->samples += GSM_SAMPLES;
 155                         pvt->datalen += 2 * GSM_SAMPLES;
 156                 }
 157         }
 158         return 0;
 159 }
 160
 161 /*! \brief store samples into working buffer for later decode */
 162 static int lintogsm_framein(struct ast_trans_pvt *pvt, struct ast_frame *f)
 163 {
 164         struct gsm_translator_pvt *tmp = pvt->pvt;
 165
 166         /* XXX We should look at how old the rest of our stream is, and if it
 167            is too old, then we should overwrite it entirely, otherwise we can
 168            get artifacts of earlier talk that do not belong */
 169         if (pvt->samples + f->samples > BUFFER_SAMPLES) {
 170                 ast_log(LOG_WARNING, "Out of buffer space\n");
 171                 return -1;
 172         }
 173         memcpy(tmp->buf + pvt->samples, f->data, f->datalen);
 174         pvt->samples += f->samples;
 175         return 0;
 176 }
 177
 178 /*! \brief encode and produce a frame */
 179 static struct ast_frame *lintogsm_frameout(struct ast_trans_pvt *pvt)
 180 {
 181         struct gsm_translator_pvt *tmp = pvt->pvt;
 182         int datalen = 0;
 183         int samples = 0;
 184
 185         /* We can't work on anything less than a frame in size */
 186         if (pvt->samples < GSM_SAMPLES)
 187                 return NULL;
 188         while (pvt->samples >= GSM_SAMPLES) {
 189                 /* Encode a frame of data */
 190                 gsm_encode(tmp->gsm, tmp->buf + samples, (gsm_byte *) pvt->outbuf + datalen);
 191                 datalen += GSM_FRAME_LEN;
 192                 samples += GSM_SAMPLES;
 193                 pvt->samples -= GSM_SAMPLES;
 194         }
 195
 196         /* Move the data at the end of the buffer to the front */
 197         if (pvt->samples)
 198                 memmove(tmp->buf, tmp->buf + samples, pvt->samples * 2);
 199
 200         return ast_trans_frameout(pvt, datalen, samples);
 201 }
 202
 203 static void gsm_destroy_stuff(struct ast_trans_pvt *pvt)
 204 {
 205         struct gsm_translator_pvt *tmp = pvt->pvt;
 206         if (tmp->gsm)
 207                 gsm_destroy(tmp->gsm);
 208 }
 209
 210 static struct ast_translator gsmtolin = {
 211         .name = "gsmtolin",
 212         .srcfmt = AST_FORMAT_GSM,
 213         .dstfmt = AST_FORMAT_SLINEAR,
 214         .newpvt = gsm_new,
 215         .framein = gsmtolin_framein,
 216         .destroy = gsm_destroy_stuff,
 217         .sample = gsmtolin_sample,
 218         .buffer_samples = BUFFER_SAMPLES,
 219         .buf_size = BUFFER_SAMPLES * 2,
 220         .desc_size = sizeof (struct gsm_translator_pvt ),
 221         .plc_samples = GSM_SAMPLES,
 222 };
 223
 224 static struct ast_translator lintogsm = {
 225         .name = "lintogsm",
 226         .srcfmt = AST_FORMAT_SLINEAR,
 227         .dstfmt = AST_FORMAT_GSM,
 228         .newpvt = gsm_new,
 229         .framein = lintogsm_framein,
 230         .frameout = lintogsm_frameout,
 231         .destroy = gsm_destroy_stuff,
 232         .sample = lintogsm_sample,
 233         .desc_size = sizeof (struct gsm_translator_pvt ),
 234         .buf_size = (BUFFER_SAMPLES * GSM_FRAME_LEN + GSM_SAMPLES - 1)/GSM_SAMPLES,
 235 };
 236
 237
 238 static void parse_config(void)
 239 {
 240         struct ast_variable *var;
 241         struct ast_config *cfg = ast_config_load("codecs.conf");
 242         if (!cfg)
 243                 return;
 244         for (var = ast_variable_browse(cfg, "plc"); var; var = var->next) {
 245                if (!strcasecmp(var->name, "genericplc")) {
 246                        gsmtolin.useplc = ast_true(var->value) ? 1 : 0;
 247                        if (option_verbose > 2)
 248                                ast_verbose(VERBOSE_PREFIX_3 "codec_gsm: %susing generic PLC\n", gsmtolin.useplc ? "" : "not ");
 249                }
 250         }
 251         ast_config_destroy(cfg);
 252 }
 253
 254 /*! \brief standard module glue */
 255 static int reload(void)
 256 {
 257         parse_config();
 258         return 0;
 259 }
 260
 261 static int unload_module(void)
 262 {
 263         int res;
 264
 265         res = ast_unregister_translator(&lintogsm);
 266         if (!res)
 267                 res = ast_unregister_translator(&gsmtolin);
 268
 269         return res;
 270 }
 271
 272 static int load_module(void)
 273 {
 274         int res;
 275
 276         parse_config();
 277         res = ast_register_translator(&gsmtolin);
 278         if (!res)
 279                 res=ast_register_translator(&lintogsm);
 280         else
 281                 ast_unregister_translator(&gsmtolin);
 282
 283         return res;
 284 }
 285
 286 AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_DEFAULT, "GSM Coder/Decoder",
 287                 .load = load_module,
 288                 .unload = unload_module,
 289                 .reload = reload,
 290                );