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