xref: /third_party/ffmpeg/libavcodec/mlp.h (revision cabdff1a) 
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 "libavutil/channel_layout.h"
28
29#define SYNC_MLP        0xbb
30#define SYNC_TRUEHD     0xba
31
32/** Last possible matrix channel for each codec */
33#define MAX_MATRIX_CHANNEL_MLP      5
34#define MAX_MATRIX_CHANNEL_TRUEHD   7
35/** Maximum number of channels in a valid stream.
36 *  MLP   : 5.1 + 2 noise channels -> 8 channels
37 *  TrueHD: 7.1                    -> 8 channels
38 */
39#define MAX_CHANNELS                8
40
41/** Maximum number of matrices used in decoding; most streams have one matrix
42 *  per output channel, but some rematrix a channel (usually 0) more than once.
43 */
44#define MAX_MATRICES_MLP            6
45#define MAX_MATRICES_TRUEHD         8
46#define MAX_MATRICES                8
47
48/** Maximum number of substreams that can be decoded.
49 *  MLP's limit is 2. TrueHD supports at least up to 3.
50 */
51#define MAX_SUBSTREAMS      4
52
53/** which multiple of 48000 the maximum sample rate is */
54#define MAX_RATEFACTOR      4
55/** maximum sample frequency seen in files */
56#define MAX_SAMPLERATE      (MAX_RATEFACTOR * 48000)
57
58/** maximum number of audio samples within one access unit */
59#define MAX_BLOCKSIZE       (40 * MAX_RATEFACTOR)
60/** next power of two greater than MAX_BLOCKSIZE */
61#define MAX_BLOCKSIZE_POW2  (64 * MAX_RATEFACTOR)
62
63/** number of allowed filters */
64#define NUM_FILTERS         2
65
66/** The maximum number of taps in IIR and FIR filters. */
67#define MAX_FIR_ORDER       8
68#define MAX_IIR_ORDER       4
69
70/** Code that signals end of a stream. */
71#define END_OF_STREAM       0xd234d234
72
73#define FIR 0
74#define IIR 1
75
76/** filter data */
77typedef struct FilterParams {
78    uint8_t     order; ///< number of taps in filter
79    uint8_t     shift; ///< Right shift to apply to output of filter.
80
81    int32_t     state[MAX_FIR_ORDER];
82
83    int coeff_bits;
84    int coeff_shift;
85} FilterParams;
86
87/** sample data coding information */
88typedef struct ChannelParams {
89    FilterParams filter_params[NUM_FILTERS];
90    int32_t     coeff[NUM_FILTERS][MAX_FIR_ORDER];
91
92    int16_t     huff_offset;      ///< Offset to apply to residual values.
93    int32_t     sign_huff_offset; ///< sign/rounding-corrected version of huff_offset
94    uint8_t     codebook;         ///< Which VLC codebook to use to read residuals.
95    uint8_t     huff_lsbs;        ///< Size of residual suffix not encoded using VLC.
96} ChannelParams;
97
98/** Tables defining the Huffman codes.
99 *  There are three entropy coding methods used in MLP (four if you count
100 *  "none" as a method). These use the same sequences for codes starting with
101 *  00 or 01, but have different codes starting with 1.
102 */
103extern const uint8_t ff_mlp_huffman_tables[3][18][2];
104
105typedef struct {
106    uint8_t channel_occupancy;
107    uint8_t group1_channels;
108    uint8_t group2_channels;
109    uint8_t summary_info;
110} ChannelInformation;
111
112/** Tables defining channel information.
113 *
114 *  Possible channel arrangements are:
115 *
116 *  (Group 1)   C
117 *  (Group 1)   L,  R
118 *  (Group 1)   Lf, Rf          /  (Group 2)   S
119 *  (Group 1)   Lf, Rf          /  (Group 2)   Ls, Rs
120 *  (Group 1)   Lf, Rf          /  (Group 2)   LFE
121 *  (Group 1)   Lf, Rf          /  (Group 2)   LFE, S
122 *  (Group 1)   Lf, Rf          /  (Group 2)   LFE, Ls, Rs
123 *  (Group 1)   Lf, Rf          /  (Group 2)   C
124 *  (Group 1)   Lf, Rf          /  (Group 2)   C, S
125 *  (Group 1)   Lf, Rf          /  (Group 2)   C, Ls, Rs
126 *  (Group 1)   Lf, Rf          /  (Group 2)   C, LFE
127 *  (Group 1)   Lf, Rf          /  (Group 2)   C, LFE, S
128 *  (Group 1)   Lf, Rf          /  (Group 2)   C, LFE, Ls,  Rs
129 *  (Group 1)   Lf, Rf  C       /  (Group 2)   S
130 *  (Group 1)   Lf, Rf  C       /  (Group 2)   Ls, Rs
131 *  (Group 1)   Lf, Rf  C       /  (Group 2)   LFE
132 *  (Group 1)   Lf, Rf  C       /  (Group 2)   LFE, S
133 *  (Group 1)   Lf, Rf  C       /  (Group 2)   LFE, Ls, Rs
134 *  (Group 1)   Lf, Rf  Ls  Rs  /  (Group 2)   LFE
135 *  (Group 1)   Lf, Rf  Ls  Rs  /  (Group 2)   C
136 *  (Group 1)   Lf, Rf, Ls, Rs  /  (Group 2)   C, LFE
137 */
138extern const ChannelInformation ff_mlp_ch_info[21];
139
140#if FF_API_OLD_CHANNEL_LAYOUT
141extern const uint64_t ff_mlp_channel_layouts[12];
142#endif
143extern const AVChannelLayout ff_mlp_ch_layouts[12];
144
145/** MLP uses checksums that seem to be based on the standard CRC algorithm, but
146 *  are not (in implementation terms, the table lookup and XOR are reversed).
147 *  We can implement this behavior using a standard av_crc on all but the
148 *  last element, then XOR that with the last element.
149 */
150uint8_t  ff_mlp_checksum8 (const uint8_t *buf, unsigned int buf_size);
151uint16_t ff_mlp_checksum16(const uint8_t *buf, unsigned int buf_size);
152
153/** Calculate an 8-bit checksum over a restart header -- a non-multiple-of-8
154 *  number of bits, starting two bits into the first byte of buf.
155 */
156uint8_t ff_mlp_restart_checksum(const uint8_t *buf, unsigned int bit_size);
157
158/** XOR together all the bytes of a buffer.
159 *  Does this belong in dspcontext?
160 */
161uint8_t ff_mlp_calculate_parity(const uint8_t *buf, unsigned int buf_size);
162
163void ff_mlp_init_crc(void);
164
165/** XOR four bytes into one. */
166static inline uint8_t xor_32_to_8(uint32_t value)
167{
168    value ^= value >> 16;
169    value ^= value >>  8;
170    return value;
171}
172
173typedef enum THDChannelModifier {
174    THD_CH_MODIFIER_NOTINDICATED  = 0x0,
175    THD_CH_MODIFIER_STEREO        = 0x0, // Stereo (not Dolby Surround)
176    THD_CH_MODIFIER_LTRT          = 0x1, // Dolby Surround
177    THD_CH_MODIFIER_LBINRBIN      = 0x2, // Dolby Headphone
178    THD_CH_MODIFIER_MONO          = 0x3, // Mono or Dual Mono
179    THD_CH_MODIFIER_NOTSURROUNDEX = 0x1, // Not Dolby Digital EX
180    THD_CH_MODIFIER_SURROUNDEX    = 0x2, // Dolby Digital EX
181} THDChannelModifier;
182
183#endif /* AVCODEC_MLP_H */
184