blob: 08f749a046723d9b7dcf3368089d2bef6f4156ba
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 */ |
81 |