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mlp.h
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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 "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 
79 } FilterParams;
80 
81 /** sample data coding information */
82 typedef struct ChannelParams {
85 
86  int16_t huff_offset; ///< Offset to apply to residual values.
87  int32_t sign_huff_offset; ///< sign/rounding-corrected version of huff_offset
88  uint8_t codebook; ///< Which VLC codebook to use to read residuals.
89  uint8_t huff_lsbs; ///< Size of residual suffix not encoded using VLC.
91 
92 /** Tables defining the Huffman codes.
93  * There are three entropy coding methods used in MLP (four if you count
94  * "none" as a method). These use the same sequences for codes starting with
95  * 00 or 01, but have different codes starting with 1.
96  */
97 extern const uint8_t ff_mlp_huffman_tables[3][18][2];
98 
99 /** MLP uses checksums that seem to be based on the standard CRC algorithm, but
100  * are not (in implementation terms, the table lookup and XOR are reversed).
101  * We can implement this behavior using a standard av_crc on all but the
102  * last element, then XOR that with the last element.
103  */
104 uint8_t ff_mlp_checksum8 (const uint8_t *buf, unsigned int buf_size);
105 uint16_t ff_mlp_checksum16(const uint8_t *buf, unsigned int buf_size);
106 
107 /** Calculate an 8-bit checksum over a restart header -- a non-multiple-of-8
108  * number of bits, starting two bits into the first byte of buf.
109  */
110 uint8_t ff_mlp_restart_checksum(const uint8_t *buf, unsigned int bit_size);
111 
112 /** XOR together all the bytes of a buffer.
113  * Does this belong in dspcontext?
114  */
115 uint8_t ff_mlp_calculate_parity(const uint8_t *buf, unsigned int buf_size);
116 
117 void ff_mlp_init_crc(void);
118 
119 /** XOR four bytes into one. */
120 static inline uint8_t xor_32_to_8(uint32_t value)
121 {
122  value ^= value >> 16;
123  value ^= value >> 8;
124  return value;
125 }
126 
127 typedef enum THDChannelModifier {
129  THD_CH_MODIFIER_STEREO = 0x0, // Stereo (not Dolby Surround)
130  THD_CH_MODIFIER_LTRT = 0x1, // Dolby Surround
131  THD_CH_MODIFIER_LBINRBIN = 0x2, // Dolby Headphone
132  THD_CH_MODIFIER_MONO = 0x3, // Mono or Dual Mono
133  THD_CH_MODIFIER_NOTSURROUNDEX = 0x1, // Not Dolby Digital EX
134  THD_CH_MODIFIER_SURROUNDEX = 0x2, // Dolby Digital EX
136 
137 #endif /* AVCODEC_MLP_H */
uint8_t shift
Right shift to apply to output of filter.
Definition: mlp.h:76
FilterParams filter_params[NUM_FILTERS]
Definition: mlp.h:83
uint16_t ff_mlp_checksum16(const uint8_t *buf, unsigned int buf_size)
Definition: mlp.c:64
uint8_t
static uint8_t xor_32_to_8(uint32_t value)
XOR four bytes into one.
Definition: mlp.h:120
#define MAX_FIR_ORDER
The maximum number of taps in IIR and FIR filters.
Definition: mlp.h:64
const uint8_t ff_mlp_huffman_tables[3][18][2]
Tables defining the Huffman codes.
Definition: mlp.c:28
uint8_t ff_mlp_calculate_parity(const uint8_t *buf, unsigned int buf_size)
XOR together all the bytes of a buffer.
Definition: mlp.c:99
THDChannelModifier
Definition: mlp.h:127
int16_t huff_offset
Offset to apply to residual values.
Definition: mlp.h:86
#define NUM_FILTERS
number of allowed filters
Definition: mlp.h:61
uint8_t ff_mlp_checksum8(const uint8_t *buf, unsigned int buf_size)
MLP uses checksums that seem to be based on the standard CRC algorithm, but are not (in implementatio...
Definition: mlp.c:73
void ff_mlp_init_crc(void)
Definition: mlp.c:54
GLsizei GLboolean const GLfloat * value
Definition: opengl_enc.c:109
int32_t
int32_t coeff[NUM_FILTERS][MAX_FIR_ORDER]
Definition: mlp.h:84
uint8_t codebook
Which VLC codebook to use to read residuals.
Definition: mlp.h:88
Libavcodec external API header.
int32_t state[MAX_FIR_ORDER]
Definition: mlp.h:78
uint8_t order
number of taps in filter
Definition: mlp.h:75
void * buf
Definition: avisynth_c.h:690
filter data
Definition: mlp.h:74
uint8_t huff_lsbs
Size of residual suffix not encoded using VLC.
Definition: mlp.h:89
sample data coding information
Definition: mlp.h:82
uint8_t ff_mlp_restart_checksum(const uint8_t *buf, unsigned int bit_size)
Calculate an 8-bit checksum over a restart header – a non-multiple-of-8 number of bits...
Definition: mlp.c:80
int32_t sign_huff_offset
sign/rounding-corrected version of huff_offset
Definition: mlp.h:87