interpretor/libsndfile-1.0.25/src/ima_oki_adpcm.h

   1 /*
   2 ** Copyright (C) 2007-2011 Erik de Castro Lopo <erikd@mega-nerd.com>
   3 ** Copyright (c) 2007 <robs@users.sourceforge.net>
   4 **
   5 ** This library is free software; you can redistribute it and/or modify it
   6 ** under the terms of the GNU Lesser General Public License as published by
   7 ** the Free Software Foundation; either version 2 of the License, or (at
   8 ** your option) any later version.
   9 **
  10 ** This library is distributed in the hope that it will be useful, but
  11 ** WITHOUT ANY WARRANTY; without even the implied warranty of
  12 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser
  13 ** General Public License for more details.
  14 **
  15 ** You should have received a copy of the GNU Lesser General Public License
  16 ** along with this library.  If not, write to the Free Software Foundation,
  17 ** Fifth Floor, 51 Franklin Street, Boston, MA 02111-1301, USA.
  18 */
  19
  20 /* ADPCM: IMA, OKI <==> 16-bit PCM. */
  21
  22
  23 #define         IMA_OKI_ADPCM_CODE_LEN  256
  24 #define         IMA_OKI_ADPCM_PCM_LEN   (IMA_OKI_ADPCM_CODE_LEN *2)
  25
  26 typedef struct
  27 {
  28         /* private: */
  29         int mask ;
  30         int last_output ;
  31         int step_index ;
  32         int max_step_index ;
  33         int const * steps ;
  34
  35         /* public: */
  36         int errors ;
  37         int     code_count, pcm_count ;
  38
  39         unsigned char   codes [IMA_OKI_ADPCM_CODE_LEN] ;
  40         short                   pcm [IMA_OKI_ADPCM_PCM_LEN] ;
  41 } IMA_OKI_ADPCM ;
  42
  43 typedef enum
  44 {       IMA_OKI_ADPCM_TYPE_IMA,
  45         IMA_OKI_ADPCM_TYPE_OKI
  46 } IMA_OKI_ADPCM_TYPE ;
  47
  48 void ima_oki_adpcm_init         (IMA_OKI_ADPCM * state, IMA_OKI_ADPCM_TYPE type) ;
  49
  50 int     adpcm_decode    (IMA_OKI_ADPCM * state, int /* 0..15 */ code) ;
  51 int     adpcm_encode    (IMA_OKI_ADPCM * state, int /* -32768..32767 */ sample) ;
  52
  53 void    ima_oki_adpcm_decode_block      (IMA_OKI_ADPCM * state) ;
  54 void    ima_oki_adpcm_encode_block      (IMA_OKI_ADPCM * state) ;