1 /* adpcm.h codex functions for MS_ADPCM data 2 * (hopefully) provides interoperability with 3 * Microsoft's ADPCM format, but, as usual, 4 * see LACK-OF-WARRANTY information below. 5 * 6 * Copyright (C) 1999 Stanley J. Brooks <stabro@megsinet.net> 7 * 8 * This library is free software; you can redistribute it and/or modify it 9 * under the terms of the GNU Lesser General Public License as published by 10 * the Free Software Foundation; either version 2.1 of the License, or (at 11 * your option) any later version. 12 * 13 * This library is distributed in the hope that it will be useful, but 14 * WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser 16 * General Public License for more details. 17 * 18 * You should have received a copy of the GNU Lesser General Public License 19 * along with this library; if not, write to the Free Software Foundation, 20 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 21 * 22 */ 23 #include "sox.h" 24 25 #ifndef SAMPL 26 #define SAMPL short 27 #endif 28 29 /* default coef sets */ 30 extern const short lsx_ms_adpcm_i_coef[7][2]; 31 32 extern void *lsx_ms_adpcm_alloc(unsigned chans); 33 34 /* lsx_ms_adpcm_block_expand_i() outputs interleaved samples into one output buffer */ 35 extern const char *lsx_ms_adpcm_block_expand_i( 36 void *priv, 37 unsigned chans, /* total channels */ 38 int nCoef, 39 const short *coef, 40 const unsigned char *ibuff,/* input buffer[blockAlign] */ 41 SAMPL *obuff, /* output samples, n*chans */ 42 int n /* samples to decode PER channel, REQUIRE n % 8 == 1 */ 43 ); 44 45 extern void lsx_ms_adpcm_block_mash_i( 46 unsigned chans, /* total channels */ 47 const SAMPL *ip, /* ip[n*chans] is interleaved input samples */ 48 int n, /* samples to encode PER channel, REQUIRE */ 49 int *st, /* input/output steps, 16<=st[i] */ 50 unsigned char *obuff, /* output buffer[blockAlign] */ 51 int blockAlign /* >= 7*chans + n/2 */ 52 ); 53 54 /* Some helper functions for computing samples/block and blockalign */ 55 56 /* 57 * lsx_ms_adpcm_samples_in(dataLen, chans, blockAlign, samplesPerBlock) 58 * returns the number of samples/channel which would be 59 * in the dataLen, given the other parameters ... 60 * if input samplesPerBlock is 0, then returns the max 61 * samplesPerBlock which would go into a block of size blockAlign 62 * Yes, it is confusing usage. 63 */ 64 extern size_t lsx_ms_adpcm_samples_in( 65 size_t dataLen, 66 size_t chans, 67 size_t blockAlign, 68 size_t samplesPerBlock 69 ); 70 71 /* 72 * size_t lsx_ms_adpcm_bytes_per_block(chans, samplesPerBlock) 73 * return minimum blocksize which would be required 74 * to encode number of chans with given samplesPerBlock 75 */ 76 extern size_t lsx_ms_adpcm_bytes_per_block( 77 size_t chans, 78 size_t samplesPerBlock 79 ); 80