Globally rename the header inclusion guard names.
[libav.git] / libavcodec / mlp.h
1 /*
2 * MLP codec common header file
3 * Copyright (c) 2007-2008 Ian Caulfield
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 #ifndef AVCODEC_MLP_H
23 #define AVCODEC_MLP_H
24
25 #include <stdint.h>
26
27 #include "avcodec.h"
28
29 /** Maximum number of channels that can be decoded. */
30 #define MAX_CHANNELS 16
31
32 /** Maximum number of matrices used in decoding; most streams have one matrix
33 * per output channel, but some rematrix a channel (usually 0) more than once.
34 */
35 #define MAX_MATRICES 15
36
37 /** Maximum number of substreams that can be decoded. This could also be set
38 * higher, but I haven't seen any examples with more than two.
39 */
40 #define MAX_SUBSTREAMS 2
41
42 /** maximum sample frequency seen in files */
43 #define MAX_SAMPLERATE 192000
44
45 /** maximum number of audio samples within one access unit */
46 #define MAX_BLOCKSIZE (40 * (MAX_SAMPLERATE / 48000))
47 /** next power of two greater than MAX_BLOCKSIZE */
48 #define MAX_BLOCKSIZE_POW2 (64 * (MAX_SAMPLERATE / 48000))
49
50 /** number of allowed filters */
51 #define NUM_FILTERS 2
52
53 /** The maximum number of taps in either the IIR or FIR filter;
54 * I believe MLP actually specifies the maximum order for IIR filters as four,
55 * and that the sum of the orders of both filters must be <= 8.
56 */
57 #define MAX_FILTER_ORDER 8
58
59 /** Code that signals end of a stream. */
60 #define END_OF_STREAM 0xd234d234
61
62 #define FIR 0
63 #define IIR 1
64
65 /** filter data */
66 typedef struct {
67 uint8_t order; ///< number of taps in filter
68 uint8_t shift; ///< Right shift to apply to output of filter.
69
70 int32_t coeff[MAX_FILTER_ORDER];
71 int32_t state[MAX_FILTER_ORDER];
72 } FilterParams;
73
74 /** sample data coding information */
75 typedef struct {
76 FilterParams filter_params[NUM_FILTERS];
77
78 int16_t huff_offset; ///< Offset to apply to residual values.
79 int32_t sign_huff_offset; ///< sign/rounding-corrected version of huff_offset
80 uint8_t codebook; ///< Which VLC codebook to use to read residuals.
81 uint8_t huff_lsbs; ///< Size of residual suffix not encoded using VLC.
82 } ChannelParams;
83
84 /** Tables defining the Huffman codes.
85 * There are three entropy coding methods used in MLP (four if you count
86 * "none" as a method). These use the same sequences for codes starting with
87 * 00 or 01, but have different codes starting with 1.
88 */
89 extern const uint8_t ff_mlp_huffman_tables[3][18][2];
90
91 /** MLP uses checksums that seem to be based on the standard CRC algorithm, but
92 * are not (in implementation terms, the table lookup and XOR are reversed).
93 * We can implement this behavior using a standard av_crc on all but the
94 * last element, then XOR that with the last element.
95 */
96 uint8_t ff_mlp_checksum8 (const uint8_t *buf, unsigned int buf_size);
97 uint16_t ff_mlp_checksum16(const uint8_t *buf, unsigned int buf_size);
98
99 /** Calculate an 8-bit checksum over a restart header -- a non-multiple-of-8
100 * number of bits, starting two bits into the first byte of buf.
101 */
102 uint8_t ff_mlp_restart_checksum(const uint8_t *buf, unsigned int bit_size);
103
104 /** XOR together all the bytes of a buffer.
105 * Does this belong in dspcontext?
106 */
107 uint8_t ff_mlp_calculate_parity(const uint8_t *buf, unsigned int buf_size);
108
109 int ff_mlp_init_crc2D(AVCodecParserContext *s);
110
111 void ff_mlp_init_crc();
112
113 /** XOR four bytes into one. */
114 static inline uint8_t xor_32_to_8(uint32_t value)
115 {
116 value ^= value >> 16;
117 value ^= value >> 8;
118 return value;
119 }
120
121 #endif /* AVCODEC_MLP_H */