• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
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