FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavcodec/mlp.h
Date: 2025-10-29 00:48:36
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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 PARAM_BLOCKSIZE (1 << 7)
74 #define PARAM_MATRIX (1 << 6)
75 #define PARAM_OUTSHIFT (1 << 5)
76 #define PARAM_QUANTSTEP (1 << 4)
77 #define PARAM_FIR (1 << 3)
78 #define PARAM_IIR (1 << 2)
79 #define PARAM_HUFFOFFSET (1 << 1)
80 #define PARAM_PRESENCE (1 << 0)
81
82 #define FIR 0
83 #define IIR 1
84
85 /** filter data */
86 typedef struct FilterParams {
87 uint8_t order; ///< number of taps in filter
88 uint8_t shift; ///< Right shift to apply to output of filter.
89
90 int32_t state[MAX_FIR_ORDER];
91
92 int coeff_bits;
93 int coeff_shift;
94 } FilterParams;
95
96 /** sample data coding information */
97 typedef struct ChannelParams {
98 FilterParams filter_params[NUM_FILTERS];
99 int32_t coeff[NUM_FILTERS][MAX_FIR_ORDER];
100
101 int16_t huff_offset; ///< Offset to apply to residual values.
102 int32_t sign_huff_offset; ///< sign/rounding-corrected version of huff_offset
103 uint8_t codebook; ///< Which VLC codebook to use to read residuals.
104 uint8_t huff_lsbs; ///< Size of residual suffix not encoded using VLC.
105 } ChannelParams;
106
107 /** Tables defining the Huffman codes.
108 * There are three entropy coding methods used in MLP (four if you count
109 * "none" as a method). These use the same sequences for codes starting with
110 * 00 or 01, but have different codes starting with 1.
111 */
112 extern const uint8_t ff_mlp_huffman_tables[3][18][2];
113
114 typedef struct {
115 uint8_t channel_occupancy;
116 uint8_t group1_channels;
117 uint8_t group2_channels;
118 uint8_t summary_info;
119 } ChannelInformation;
120
121 /** Tables defining channel information.
122 *
123 * Possible channel arrangements are:
124 *
125 * (Group 1) C
126 * (Group 1) L, R
127 * (Group 1) Lf, Rf / (Group 2) S
128 * (Group 1) Lf, Rf / (Group 2) Ls, Rs
129 * (Group 1) Lf, Rf / (Group 2) LFE
130 * (Group 1) Lf, Rf / (Group 2) LFE, S
131 * (Group 1) Lf, Rf / (Group 2) LFE, Ls, Rs
132 * (Group 1) Lf, Rf / (Group 2) C
133 * (Group 1) Lf, Rf / (Group 2) C, S
134 * (Group 1) Lf, Rf / (Group 2) C, Ls, Rs
135 * (Group 1) Lf, Rf / (Group 2) C, LFE
136 * (Group 1) Lf, Rf / (Group 2) C, LFE, S
137 * (Group 1) Lf, Rf / (Group 2) C, LFE, Ls, Rs
138 * (Group 1) Lf, Rf C / (Group 2) S
139 * (Group 1) Lf, Rf C / (Group 2) Ls, Rs
140 * (Group 1) Lf, Rf C / (Group 2) LFE
141 * (Group 1) Lf, Rf C / (Group 2) LFE, S
142 * (Group 1) Lf, Rf C / (Group 2) LFE, Ls, Rs
143 * (Group 1) Lf, Rf Ls Rs / (Group 2) LFE
144 * (Group 1) Lf, Rf Ls Rs / (Group 2) C
145 * (Group 1) Lf, Rf, Ls, Rs / (Group 2) C, LFE
146 */
147 extern const ChannelInformation ff_mlp_ch_info[21];
148
149 extern const AVChannelLayout ff_mlp_ch_layouts[12];
150
151 /** MLP uses checksums that seem to be based on the standard CRC algorithm, but
152 * are not (in implementation terms, the table lookup and XOR are reversed).
153 * We can implement this behavior using a standard av_crc on all but the
154 * last element, then XOR that with the last element.
155 */
156 uint8_t ff_mlp_checksum8 (const uint8_t *buf, unsigned int buf_size);
157 uint16_t ff_mlp_checksum16(const uint8_t *buf, unsigned int buf_size);
158
159 /** Calculate an 8-bit checksum over a restart header -- a non-multiple-of-8
160 * number of bits, starting two bits into the first byte of buf.
161 */
162 uint8_t ff_mlp_restart_checksum(const uint8_t *buf, unsigned int bit_size);
163
164 /** XOR together all the bytes of a buffer.
165 * Does this belong in dspcontext?
166 */
167 uint8_t ff_mlp_calculate_parity(const uint8_t *buf, unsigned int buf_size);
168
169 void ff_mlp_init_crc(void);
170
171 /** XOR four bytes into one. */
172 70066 static inline uint8_t xor_32_to_8(uint32_t value)
173 {
174 70066 value ^= value >> 16;
175 70066 value ^= value >> 8;
176 70066 return value;
177 }
178
179 typedef enum THDChannelModifier {
180 THD_CH_MODIFIER_NOTINDICATED = 0x0,
181 THD_CH_MODIFIER_STEREO = 0x0, // Stereo (not Dolby Surround)
182 THD_CH_MODIFIER_LTRT = 0x1, // Dolby Surround
183 THD_CH_MODIFIER_LBINRBIN = 0x2, // Dolby Headphone
184 THD_CH_MODIFIER_MONO = 0x3, // Mono or Dual Mono
185 THD_CH_MODIFIER_NOTSURROUNDEX = 0x1, // Not Dolby Digital EX
186 THD_CH_MODIFIER_SURROUNDEX = 0x2, // Dolby Digital EX
187 } THDChannelModifier;
188
189 #endif /* AVCODEC_MLP_H */
190