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/* adpcm.h codex functions for MS_ADPCM data
* (hopefully) provides interoperability with
* Microsoft's ADPCM format, but, as usual,
* see LACK-OF-WARRANTY information below.
*
* Copyright (C) 1999 Stanley J. Brooks <stabro@megsinet.net>
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or (at
* your option) any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
* General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
#include "sox.h"
#ifndef SAMPL
#define SAMPL short
#endif
/* default coef sets */
extern const short lsx_ms_adpcm_i_coef[7][2];
extern void *lsx_ms_adpcm_alloc(unsigned chans);
/* lsx_ms_adpcm_block_expand_i() outputs interleaved samples into one output buffer */
extern const char *lsx_ms_adpcm_block_expand_i(
void *priv,
unsigned chans, /* total channels */
int nCoef,
const short *coef,
const unsigned char *ibuff,/* input buffer[blockAlign] */
SAMPL *obuff, /* output samples, n*chans */
int n /* samples to decode PER channel, REQUIRE n % 8 == 1 */
);
extern void lsx_ms_adpcm_block_mash_i(
unsigned chans, /* total channels */
const SAMPL *ip, /* ip[n*chans] is interleaved input samples */
int n, /* samples to encode PER channel, REQUIRE */
int *st, /* input/output steps, 16<=st[i] */
unsigned char *obuff, /* output buffer[blockAlign] */
int blockAlign /* >= 7*chans + n/2 */
);
/* Some helper functions for computing samples/block and blockalign */
/*
* lsx_ms_adpcm_samples_in(dataLen, chans, blockAlign, samplesPerBlock)
* returns the number of samples/channel which would be
* in the dataLen, given the other parameters ...
* if input samplesPerBlock is 0, then returns the max
* samplesPerBlock which would go into a block of size blockAlign
* Yes, it is confusing usage.
*/
extern size_t lsx_ms_adpcm_samples_in(
size_t dataLen,
size_t chans,
size_t blockAlign,
size_t samplesPerBlock
);
/*
* size_t lsx_ms_adpcm_bytes_per_block(chans, samplesPerBlock)
* return minimum blocksize which would be required
* to encode number of chans with given samplesPerBlock
*/
extern size_t lsx_ms_adpcm_bytes_per_block(
size_t chans,
size_t samplesPerBlock
);
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