Statistics
| Branch: | Revision:

ffmpeg / libavcodec / ac3dec.h @ 3da11804

History | View | Annotate | Download (9.14 KB)

1
/*
2
 * Common code between the AC-3 and E-AC-3 decoders
3
 * Copyright (c) 2007 Bartlomiej Wolowiec <bartek.wolowiec@gmail.com>
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
/**
23
 * @file libavcodec/ac3.h
24
 * Common code between the AC-3 and E-AC-3 decoders.
25
 */
26

    
27
#ifndef AVCODEC_AC3DEC_H
28
#define AVCODEC_AC3DEC_H
29

    
30
#include "libavutil/lfg.h"
31
#include "ac3.h"
32
#include "get_bits.h"
33
#include "dsputil.h"
34
#include "fft.h"
35

    
36
/* override ac3.h to include coupling channel */
37
#undef AC3_MAX_CHANNELS
38
#define AC3_MAX_CHANNELS 7
39
#define CPL_CH 0
40

    
41
#define AC3_OUTPUT_LFEON  8
42

    
43
#define AC3_MAX_COEFS   256
44
#define AC3_BLOCK_SIZE  256
45
#define MAX_BLOCKS        6
46

    
47
typedef struct {
48
    AVCodecContext *avctx;                  ///< parent context
49
    GetBitContext gbc;                      ///< bitstream reader
50
    uint8_t *input_buffer;                  ///< temp buffer to prevent overread
51

    
52
///@defgroup bsi bit stream information
53
///@{
54
    int frame_type;                         ///< frame type                             (strmtyp)
55
    int substreamid;                        ///< substream identification
56
    int frame_size;                         ///< current frame size, in bytes
57
    int bit_rate;                           ///< stream bit rate, in bits-per-second
58
    int sample_rate;                        ///< sample frequency, in Hz
59
    int num_blocks;                         ///< number of audio blocks
60
    int channel_mode;                       ///< channel mode                           (acmod)
61
    int channel_layout;                     ///< channel layout
62
    int lfe_on;                             ///< lfe channel in use
63
    int channel_map;                        ///< custom channel map
64
    int center_mix_level;                   ///< Center mix level index
65
    int surround_mix_level;                 ///< Surround mix level index
66
    int eac3;                               ///< indicates if current frame is E-AC-3
67
///@}
68

    
69
///@defgroup audfrm frame syntax parameters
70
    int snr_offset_strategy;                ///< SNR offset strategy                    (snroffststr)
71
    int block_switch_syntax;                ///< block switch syntax enabled            (blkswe)
72
    int dither_flag_syntax;                 ///< dither flag syntax enabled             (dithflage)
73
    int bit_allocation_syntax;              ///< bit allocation model syntax enabled    (bamode)
74
    int fast_gain_syntax;                   ///< fast gain codes enabled                (frmfgaincode)
75
    int dba_syntax;                         ///< delta bit allocation syntax enabled    (dbaflde)
76
    int skip_syntax;                        ///< skip field syntax enabled              (skipflde)
77
 ///@}
78

    
79
///@defgroup cpl standard coupling
80
    int cpl_in_use[MAX_BLOCKS];             ///< coupling in use                        (cplinu)
81
    int cpl_strategy_exists[MAX_BLOCKS];    ///< coupling strategy exists               (cplstre)
82
    int channel_in_cpl[AC3_MAX_CHANNELS];   ///< channel in coupling                    (chincpl)
83
    int phase_flags_in_use;                 ///< phase flags in use                     (phsflginu)
84
    int phase_flags[18];                    ///< phase flags                            (phsflg)
85
    int num_cpl_bands;                      ///< number of coupling bands               (ncplbnd)
86
    uint8_t cpl_band_sizes[18];             ///< number of coeffs in each coupling band
87
    int firstchincpl;                       ///< first channel in coupling
88
    int first_cpl_coords[AC3_MAX_CHANNELS]; ///< first coupling coordinates states      (firstcplcos)
89
    int cpl_coords[AC3_MAX_CHANNELS][18];   ///< coupling coordinates                   (cplco)
90
///@}
91

    
92
///@defgroup aht adaptive hybrid transform
93
    int channel_uses_aht[AC3_MAX_CHANNELS];                         ///< channel AHT in use (chahtinu)
94
    int pre_mantissa[AC3_MAX_CHANNELS][AC3_MAX_COEFS][MAX_BLOCKS];  ///< pre-IDCT mantissas
95
///@}
96

    
97
///@defgroup channel channel
98
    int fbw_channels;                           ///< number of full-bandwidth channels
99
    int channels;                               ///< number of total channels
100
    int lfe_ch;                                 ///< index of LFE channel
101
    float downmix_coeffs[AC3_MAX_CHANNELS][2];  ///< stereo downmix coefficients
102
    int downmixed;                              ///< indicates if coeffs are currently downmixed
103
    int output_mode;                            ///< output channel configuration
104
    int out_channels;                           ///< number of output channels
105
///@}
106

    
107
///@defgroup dynrng dynamic range
108
    float dynamic_range[2];                 ///< dynamic range
109
///@}
110

    
111
///@defgroup bandwidth bandwidth
112
    int start_freq[AC3_MAX_CHANNELS];       ///< start frequency bin                    (strtmant)
113
    int end_freq[AC3_MAX_CHANNELS];         ///< end frequency bin                      (endmant)
114
///@}
115

    
116
///@defgroup rematrixing rematrixing
117
    int num_rematrixing_bands;              ///< number of rematrixing bands            (nrematbnd)
118
    int rematrixing_flags[4];               ///< rematrixing flags                      (rematflg)
119
///@}
120

    
121
///@defgroup exponents exponents
122
    int num_exp_groups[AC3_MAX_CHANNELS];           ///< Number of exponent groups      (nexpgrp)
123
    int8_t dexps[AC3_MAX_CHANNELS][AC3_MAX_COEFS];  ///< decoded exponents
124
    int exp_strategy[MAX_BLOCKS][AC3_MAX_CHANNELS]; ///< exponent strategies            (expstr)
125
///@}
126

    
127
///@defgroup bitalloc bit allocation
128
    AC3BitAllocParameters bit_alloc_params;         ///< bit allocation parameters
129
    int first_cpl_leak;                             ///< first coupling leak state      (firstcplleak)
130
    int snr_offset[AC3_MAX_CHANNELS];               ///< signal-to-noise ratio offsets  (snroffst)
131
    int fast_gain[AC3_MAX_CHANNELS];                ///< fast gain values/SMR's         (fgain)
132
    uint8_t bap[AC3_MAX_CHANNELS][AC3_MAX_COEFS];   ///< bit allocation pointers
133
    int16_t psd[AC3_MAX_CHANNELS][AC3_MAX_COEFS];   ///< scaled exponents
134
    int16_t band_psd[AC3_MAX_CHANNELS][50];         ///< interpolated exponents
135
    int16_t mask[AC3_MAX_CHANNELS][50];             ///< masking curve values
136
    int dba_mode[AC3_MAX_CHANNELS];                 ///< delta bit allocation mode
137
    int dba_nsegs[AC3_MAX_CHANNELS];                ///< number of delta segments
138
    uint8_t dba_offsets[AC3_MAX_CHANNELS][8];       ///< delta segment offsets
139
    uint8_t dba_lengths[AC3_MAX_CHANNELS][8];       ///< delta segment lengths
140
    uint8_t dba_values[AC3_MAX_CHANNELS][8];        ///< delta values for each segment
141
///@}
142

    
143
///@defgroup dithering zero-mantissa dithering
144
    int dither_flag[AC3_MAX_CHANNELS];      ///< dither flags                           (dithflg)
145
    AVLFG dith_state;                       ///< for dither generation
146
///@}
147

    
148
///@defgroup imdct IMDCT
149
    int block_switch[AC3_MAX_CHANNELS];     ///< block switch flags                     (blksw)
150
    FFTContext imdct_512;                   ///< for 512 sample IMDCT
151
    FFTContext imdct_256;                   ///< for 256 sample IMDCT
152
///@}
153

    
154
///@defgroup opt optimization
155
    DSPContext dsp;                         ///< for optimization
156
    float add_bias;                         ///< offset for float_to_int16 conversion
157
    float mul_bias;                         ///< scaling for float_to_int16 conversion
158
///@}
159

    
160
///@defgroup arrays aligned arrays
161
    DECLARE_ALIGNED(16, int,   fixed_coeffs)[AC3_MAX_CHANNELS][AC3_MAX_COEFS];       ///> fixed-point transform coefficients
162
    DECLARE_ALIGNED(16, float, transform_coeffs)[AC3_MAX_CHANNELS][AC3_MAX_COEFS];   ///< transform coefficients
163
    DECLARE_ALIGNED(16, float, delay)[AC3_MAX_CHANNELS][AC3_BLOCK_SIZE];             ///< delay - added to the next block
164
    DECLARE_ALIGNED(16, float, window)[AC3_BLOCK_SIZE];                              ///< window coefficients
165
    DECLARE_ALIGNED(16, float, tmp_output)[AC3_BLOCK_SIZE];                          ///< temporary storage for output before windowing
166
    DECLARE_ALIGNED(16, float, output)[AC3_MAX_CHANNELS][AC3_BLOCK_SIZE];            ///< output after imdct transform and windowing
167
///@}
168
} AC3DecodeContext;
169

    
170
/**
171
 * Parse the E-AC-3 frame header.
172
 * This parses both the bit stream info and audio frame header.
173
 */
174
int ff_eac3_parse_header(AC3DecodeContext *s);
175

    
176
/**
177
 * Decode mantissas in a single channel for the entire frame.
178
 * This is used when AHT mode is enabled.
179
 */
180
void ff_eac3_decode_transform_coeffs_aht_ch(AC3DecodeContext *s, int ch);
181

    
182
void ff_ac3_downmix_c(float (*samples)[256], float (*matrix)[2],
183
                      int out_ch, int in_ch, int len);
184

    
185
#endif /* AVCODEC_AC3DEC_H */