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adx.h
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1 /*
2  * ADX ADPCM codecs
3  * Copyright (c) 2001,2003 BERO
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
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  *
12  * FFmpeg is distributed in the hope that it will be useful,
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
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 /**
23  * @file
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 
31 #ifndef AVCODEC_ADX_H
32 #define AVCODEC_ADX_H
33 
34 #include <stdint.h>
35 
36 #include "avcodec.h"
37 
38 typedef struct ADXChannelState {
39  int s1,s2;
41 
42 typedef struct ADXContext {
44  int channels;
47  int eof;
48  int cutoff;
49  int coeff[2];
50 } ADXContext;
51 
52 #define COEFF_BITS 12
53 
54 #define BLOCK_SIZE 18
55 #define BLOCK_SAMPLES 32
56 
57 /**
58  * Calculate LPC coefficients based on cutoff frequency and sample rate.
59  *
60  * @param cutoff cutoff frequency
61  * @param sample_rate sample rate
62  * @param bits number of bits used to quantize coefficients
63  * @param[out] coeff 2 quantized LPC coefficients
64  */
65 void ff_adx_calculate_coeffs(int cutoff, int sample_rate, int bits, int *coeff);
66 
67 /**
68  * Decode ADX stream header.
69  * Sets avctx->channels and avctx->sample_rate.
70  *
71  * @param avctx codec context
72  * @param buf header data
73  * @param bufsize data size, should be at least 24 bytes
74  * @param[out] header_size size of ADX header
75  * @param[out] coeff 2 LPC coefficients, can be NULL
76  * @return data offset or negative error code if header is invalid
77  */
78 int avpriv_adx_decode_header(AVCodecContext *avctx, const uint8_t *buf,
79  int bufsize, int *header_size, int *coeff);
80 
81 #endif /* AVCODEC_ADX_H */