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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 {
43  int channels;
46  int eof;
47  int cutoff;
48  int coeff[2];
49 } ADXContext;
50 
51 #define COEFF_BITS 12
52 
53 #define BLOCK_SIZE 18
54 #define BLOCK_SAMPLES 32
55 
56 /**
57  * Calculate LPC coefficients based on cutoff frequency and sample rate.
58  *
59  * @param cutoff cutoff frequency
60  * @param sample_rate sample rate
61  * @param bits number of bits used to quantize coefficients
62  * @param[out] coeff 2 quantized LPC coefficients
63  */
64 void ff_adx_calculate_coeffs(int cutoff, int sample_rate, int bits, int *coeff);
65 
66 /**
67  * Decode ADX stream header.
68  * Sets avctx->channels and avctx->sample_rate.
69  *
70  * @param avctx codec context
71  * @param buf header data
72  * @param bufsize data size, should be at least 24 bytes
73  * @param[out] header_size size of ADX header
74  * @param[out] coeff 2 LPC coefficients, can be NULL
75  * @return data offset or negative error code if header is invalid
76  */
78  int bufsize, int *header_size, int *coeff);
79 
80 #endif /* AVCODEC_ADX_H */
int coeff[2]
Definition: adx.h:48
uint8_t bits
Definition: crc.c:295
uint8_t
int ff_adx_decode_header(AVCodecContext *avctx, const uint8_t *buf, int bufsize, int *header_size, int *coeff)
Decode ADX stream header.
Definition: adx.c:38
Libavcodec external API header.
int header_parsed
Definition: adx.h:45
sample_rate
main external API structure.
Definition: avcodec.h:1252
void * buf
Definition: avisynth_c.h:553
Definition: adx.h:42
int s2
Definition: adx.h:39
int cutoff
Definition: adx.h:47
int eof
Definition: adx.h:46
int s1
Definition: adx.h:39
ADXChannelState prev[2]
Definition: adx.h:44
static const double coeff[2][5]
Definition: vf_owdenoise.c:71
void ff_adx_calculate_coeffs(int cutoff, int sample_rate, int bits, int *coeff)
Calculate LPC coefficients based on cutoff frequency and sample rate.
Definition: adx.c:26
int channels
Definition: adx.h:43