src/cvsd.h

   1 /*      libSoX DVMS format module (implementation in cvsd.c)
   2  *
   3  *      Copyright (C) 1996-2007 Thomas Sailer and SoX Contributors
   4  *      Thomas Sailer (sailer@ife.ee.ethz.ch) (HB9JNX/AE4WA)
   5  *      Swiss Federal Institute of Technology, Electronics Lab
   6  *
   7  * This library is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU Lesser General Public License as published by
   9  * the Free Software Foundation; either version 2.1 of the License, or (at
  10  * your option) any later version.
  11  *
  12  * This library is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser
  15  * General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public License
  18  * along with this library; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  20  *
  21  */
  22 #include "sox_i.h"
  23
  24 #define CVSD_ENC_FILTERLEN 16  /* PCM sampling rate */
  25 #define CVSD_DEC_FILTERLEN 48  /* CVSD sampling rate */
  26
  27 typedef struct {
  28   struct {
  29     unsigned overload;
  30     float mla_int;
  31     float mla_tc0;
  32     float mla_tc1;
  33     unsigned phase;
  34     unsigned phase_inc;
  35     float v_min, v_max;
  36   } com;
  37   union {
  38     struct {
  39       /* mirror circular buffer */
  40       float output_filter[CVSD_DEC_FILTERLEN*2];
  41       unsigned offset; /* into output_filter; always in first half */
  42     } dec;
  43     struct {
  44       float recon_int;
  45       /* mirror circular buffer */
  46       float input_filter[CVSD_ENC_FILTERLEN*2];
  47       unsigned offset; /* into input_filter; always in first half */
  48     } enc;
  49   } c;
  50   struct {
  51     unsigned char shreg;
  52     unsigned mask;
  53     unsigned cnt;
  54   } bit;
  55   unsigned bytes_written;
  56   unsigned cvsd_rate;
  57 } cvsd_priv_t;
  58
  59 int lsx_cvsdstartread(sox_format_t * ft);
  60 int lsx_cvsdstartwrite(sox_format_t * ft);
  61 size_t lsx_cvsdread(sox_format_t * ft, sox_sample_t *buf, size_t nsamp);
  62 size_t lsx_cvsdwrite(sox_format_t * ft, const sox_sample_t *buf, size_t nsamp);
  63 int lsx_cvsdstopread(sox_format_t * ft);
  64 int lsx_cvsdstopwrite(sox_format_t * ft);
  65
  66 int lsx_dvmsstartread(sox_format_t * ft);
  67 int lsx_dvmsstartwrite(sox_format_t * ft);
  68 int lsx_dvmsstopwrite(sox_format_t * ft);