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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; | |
40 | } ADXChannelState; | |
41 | ||
42 | typedef struct ADXContext { | |
43 | int channels; | |
44 | ADXChannelState prev[2]; | |
45 | int header_parsed; | |
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 | */ | |
77 | int ff_adx_decode_header(AVCodecContext *avctx, const uint8_t *buf, | |
78 | int bufsize, int *header_size, int *coeff); | |
79 | ||
80 | #endif /* AVCODEC_ADX_H */ |