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 */
77 typedef 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 */
88 typedef 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  */
103 extern const uint8_t ff_mlp_huffman_tables[3][18][2];
104 
105 typedef 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  */
138 extern const ChannelInformation ff_mlp_ch_info[21];
139 
140 #if FF_API_OLD_CHANNEL_LAYOUT
141 extern const uint64_t ff_mlp_channel_layouts[12];
142 #endif
143 extern 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  */
150 uint8_t  ff_mlp_checksum8 (const uint8_t *buf, unsigned int buf_size);
151 uint16_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  */
156 uint8_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  */
161 uint8_t ff_mlp_calculate_parity(const uint8_t *buf, unsigned int buf_size);
162 
163 void ff_mlp_init_crc(void);
164 
165 /** XOR four bytes into one. */
xor_32_to_8(uint32_t value)166 static inline uint8_t xor_32_to_8(uint32_t value)
167 {
168     value ^= value >> 16;
169     value ^= value >>  8;
170     return value;
171 }
172 
173 typedef 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