src/adpcms.h

   1 /* libSoX ADPCM codecs: IMA, OKI, CL.   (c) 2007-8 robs@users.sourceforge.net
   2  *
   3  * This library is free software; you can redistribute it and/or modify it
   4  * under the terms of the GNU Lesser General Public License as published by
   5  * the Free Software Foundation; either version 2.1 of the License, or (at
   6  * your option) any later version.
   7  *
   8  * This library is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU Lesser General Public License
  14  * along with this library; if not, write to the Free Software Foundation,
  15  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  16  */
  17
  18 typedef struct {
  19   int max_step_index;
  20   int sign;
  21   int shift;
  22   int const * steps;
  23   int const * changes;
  24   int mask;
  25 } adpcm_setup_t;
  26
  27 typedef struct {
  28   adpcm_setup_t setup;
  29   int last_output;
  30   int step_index;
  31   int errors;
  32 } adpcm_t;
  33
  34 void lsx_adpcm_init(adpcm_t * p, int type, int first_sample);
  35 int lsx_adpcm_decode(int code, adpcm_t * p);
  36 int lsx_adpcm_encode(int sample, adpcm_t * p);
  37
  38 typedef struct {
  39   adpcm_t encoder;
  40   struct {
  41     uint8_t byte;               /* write store */
  42     uint8_t flag;
  43   } store;
  44   sox_fileinfo_t file;
  45 } adpcm_io_t;
  46
  47 /* Format methods */
  48 void lsx_adpcm_reset(adpcm_io_t * state, sox_encoding_t type);
  49 int lsx_adpcm_oki_start(sox_format_t * ft, adpcm_io_t * state);
  50 int lsx_adpcm_ima_start(sox_format_t * ft, adpcm_io_t * state);
  51 size_t lsx_adpcm_read(sox_format_t * ft, adpcm_io_t * state, sox_sample_t *buffer, size_t len);
  52 int lsx_adpcm_stopread(sox_format_t * ft, adpcm_io_t * state);
  53 size_t lsx_adpcm_write(sox_format_t * ft, adpcm_io_t * state, const sox_sample_t *buffer, size_t length);
  54 void lsx_adpcm_flush(sox_format_t * ft, adpcm_io_t * state);
  55 int lsx_adpcm_stopwrite(sox_format_t * ft, adpcm_io_t * state);