FFmpeg/libavcodec/adpcm_data.c

/*
 * Copyright (c) 2001-2003 The ffmpeg Project
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg 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.
 *
 * FFmpeg 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 FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * ADPCM tables
 */

#include <stdint.h>

/* ff_adpcm_step_table[] and ff_adpcm_index_table[] are from the ADPCM
   reference source */
/* This is the index table: */
const int8_t ff_adpcm_index_table[16] = {
    -1, -1, -1, -1, 2, 4, 6, 8,
    -1, -1, -1, -1, 2, 4, 6, 8,
};

/**
 * This is the step table. Note that many programs use slight deviations from
 * this table, but such deviations are negligible:
 */
const int16_t ff_adpcm_step_table[89] = {
    7, 8, 9, 10, 11, 12, 13, 14, 16, 17,
    19, 21, 23, 25, 28, 31, 34, 37, 41, 45,
    50, 55, 60, 66, 73, 80, 88, 97, 107, 118,
    130, 143, 157, 173, 190, 209, 230, 253, 279, 307,
    337, 371, 408, 449, 494, 544, 598, 658, 724, 796,
    876, 963, 1060, 1166, 1282, 1411, 1552, 1707, 1878, 2066,
    2272, 2499, 2749, 3024, 3327, 3660, 4026, 4428, 4871, 5358,
    5894, 6484, 7132, 7845, 8630, 9493, 10442, 11487, 12635, 13899,
    15289, 16818, 18500, 20350, 22385, 24623, 27086, 29794, 32767
};

/* These are for MS-ADPCM */
/* ff_adpcm_AdaptationTable[], ff_adpcm_AdaptCoeff1[], and
   ff_adpcm_AdaptCoeff2[] are from libsndfile */
const int16_t ff_adpcm_AdaptationTable[] = {
        230, 230, 230, 230, 307, 409, 512, 614,
        768, 614, 512, 409, 307, 230, 230, 230
};

/** Divided by 4 to fit in 8-bit integers */
const uint8_t ff_adpcm_AdaptCoeff1[] = {
        64, 128, 0, 48, 60, 115, 98
};

/** Divided by 4 to fit in 8-bit integers */
const int8_t ff_adpcm_AdaptCoeff2[] = {
        0, -64, 0, 16, 0, -52, -58
};

const int16_t ff_adpcm_yamaha_indexscale[] = {
    230, 230, 230, 230, 307, 409, 512, 614,
    230, 230, 230, 230, 307, 409, 512, 614
};

const int8_t ff_adpcm_yamaha_difflookup[] = {
    1, 3, 5, 7, 9, 11, 13, 15,
    -1, -3, -5, -7, -9, -11, -13, -15
};