src/ima_rw.h

   1 /* libSoX ima_rw.h -- codex utilities for WAV_FORMAT_IMA_ADPCM
   2  * Copyright (C) 1999 Stanley J. Brooks <stabro@megsinet.net>
   3  *
   4  * This library is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU Lesser General Public License as published by
   6  * the Free Software Foundation; either version 2.1 of the License, or (at
   7  * your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public License
  15  * along with this library; if not, write to the Free Software Foundation,
  16  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  17
  18 */
  19
  20 #include "sox.h"
  21
  22 #ifndef SAMPL
  23 #define SAMPL short
  24 #endif
  25
  26 /*
  27  * call lsx_ima_init_table() before any other Ima* functions,
  28  * to create the fast lookup tables
  29  */
  30 extern void lsx_ima_init_table(void);
  31
  32 /* lsx_ima_block_expand_i() outputs interleaved samples into one output buffer */
  33 extern void lsx_ima_block_expand_i(
  34         unsigned chans,          /* total channels             */
  35         const unsigned char *ibuff,/* input buffer[blockAlign]   */
  36         SAMPL *obuff,       /* output samples, n*chans    */
  37         int n               /* samples to decode PER channel, REQUIRE n % 8 == 1  */
  38 );
  39
  40 /* lsx_ima_block_expand_m() outputs non-interleaved samples into chan separate output buffers */
  41 extern void lsx_ima_block_expand_m(
  42         unsigned chans,          /* total channels             */
  43         const unsigned char *ibuff,/* input buffer[blockAlign]   */
  44         SAMPL **obuffs,     /* chan output sample buffers, each takes n samples */
  45         int n               /* samples to decode PER channel, REQUIRE n % 8 == 1  */
  46 );
  47
  48 /* mash one block.  if you want to use opt>0, 9 is a reasonable value */
  49 extern void lsx_ima_block_mash_i(
  50         unsigned chans,          /* total channels */
  51         const SAMPL *ip,    /* ip[] is interleaved input samples */
  52         int n,              /* samples to encode PER channel, REQUIRE n % 8 == 1 */
  53         int *st,            /* input/output state[chans], REQUIRE 0 <= st[ch] <= ISSTMAX */
  54         unsigned char *obuff, /* output buffer[blockAlign] */
  55         int opt             /* non-zero allows some cpu-intensive code to improve output */
  56 );
  57
  58 /* Some helper functions for computing samples/block and blockalign */
  59
  60 /*
  61  * lsx_ima_samples_in(dataLen, chans, blockAlign, samplesPerBlock)
  62  *  returns the number of samples/channel which would go
  63  *  in the dataLen, given the other parameters ...
  64  *  if input samplesPerBlock is 0, then returns the max
  65  *  samplesPerBlock which would go into a block of size blockAlign
  66  *  Yes, it is confusing usage.
  67  */
  68 extern size_t lsx_ima_samples_in(
  69         size_t dataLen,
  70         size_t chans,
  71         size_t blockAlign,
  72         size_t samplesPerBlock
  73 );
  74
  75 /*
  76  * size_t lsx_ima_bytes_per_block(chans, samplesPerBlock)
  77  *   return minimum blocksize which would be required
  78  *   to encode number of chans with given samplesPerBlock
  79  */
  80 extern size_t lsx_ima_bytes_per_block(
  81         size_t chans,
  82         size_t samplesPerBlock
  83 );
  84