adx: calculate correct LPC coeffs
[libav.git] / libavcodec / adx.h
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1/*
2 * ADX ADPCM codecs
3 * Copyright (c) 2001,2003 BERO
4 *
2912e87a 5 * This file is part of Libav.
c31dea61 6 *
2912e87a 7 * Libav is free software; you can redistribute it and/or
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8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
2912e87a 12 * Libav is distributed in the hope that it will be useful,
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13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
2912e87a 18 * License along with Libav; if not, write to the Free Software
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19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22/**
ba87f080 23 * @file
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24 * SEGA CRI adx codecs.
25 *
26 * Reference documents:
27 * http://ku-www.ss.titech.ac.jp/~yatsushi/adx.html
28 * adx2wav & wav2adx http://www.geocities.co.jp/Playtown/2004/
29 */
30
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31#ifndef AVCODEC_ADX_H
32#define AVCODEC_ADX_H
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33
34typedef struct {
35 int s1,s2;
dd1b9f7c 36} ADXChannelState;
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37
38typedef struct {
837bbd19 39 int channels;
dd1b9f7c 40 ADXChannelState prev[2];
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41 int header_parsed;
42 unsigned char dec_temp[18*2];
43 int in_temp;
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44 int cutoff;
45 int coeff[2];
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46} ADXContext;
47
954d94dd 48#define COEFF_BITS 12
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49
50/**
51 * Calculate LPC coefficients based on cutoff frequency and sample rate.
52 *
53 * @param cutoff cutoff frequency
54 * @param sample_rate sample rate
55 * @param bits number of bits used to quantize coefficients
56 * @param[out] coeff 2 quantized LPC coefficients
57 */
58void ff_adx_calculate_coeffs(int cutoff, int sample_rate, int bits, int *coeff);
c31dea61 59
98790382 60#endif /* AVCODEC_ADX_H */