1/*
2 * AAC definitions and structures
3 * Copyright (c) 2005-2006 Oded Shimon ( ods15 ods15 dyndns org )
4 * Copyright (c) 2006-2007 Maxim Gavrilov ( maxim.gavrilov gmail com )
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23/**
24 * @file
25 * AAC definitions and structures
26 * @author Oded Shimon  ( ods15 ods15 dyndns org )
27 * @author Maxim Gavrilov ( maxim.gavrilov gmail com )
28 */
29
30#ifndef AVCODEC_AAC_H
31#define AVCODEC_AAC_H
32
33#include "avcodec.h"
34#include "dsputil.h"
35#include "fft.h"
36#include "mpeg4audio.h"
37#include "sbr.h"
38
39#include <stdint.h>
40
41#define AAC_INIT_VLC_STATIC(num, size) \
42    INIT_VLC_STATIC(&vlc_spectral[num], 8, ff_aac_spectral_sizes[num], \
43         ff_aac_spectral_bits[num], sizeof( ff_aac_spectral_bits[num][0]), sizeof( ff_aac_spectral_bits[num][0]), \
44        ff_aac_spectral_codes[num], sizeof(ff_aac_spectral_codes[num][0]), sizeof(ff_aac_spectral_codes[num][0]), \
45        size);
46
47#define MAX_CHANNELS 64
48#define MAX_ELEM_ID 16
49
50#define TNS_MAX_ORDER 20
51
52enum RawDataBlockType {
53    TYPE_SCE,
54    TYPE_CPE,
55    TYPE_CCE,
56    TYPE_LFE,
57    TYPE_DSE,
58    TYPE_PCE,
59    TYPE_FIL,
60    TYPE_END,
61};
62
63enum ExtensionPayloadID {
64    EXT_FILL,
65    EXT_FILL_DATA,
66    EXT_DATA_ELEMENT,
67    EXT_DYNAMIC_RANGE = 0xb,
68    EXT_SBR_DATA      = 0xd,
69    EXT_SBR_DATA_CRC  = 0xe,
70};
71
72enum WindowSequence {
73    ONLY_LONG_SEQUENCE,
74    LONG_START_SEQUENCE,
75    EIGHT_SHORT_SEQUENCE,
76    LONG_STOP_SEQUENCE,
77};
78
79enum BandType {
80    ZERO_BT        = 0,     ///< Scalefactors and spectral data are all zero.
81    FIRST_PAIR_BT  = 5,     ///< This and later band types encode two values (rather than four) with one code word.
82    ESC_BT         = 11,    ///< Spectral data are coded with an escape sequence.
83    NOISE_BT       = 13,    ///< Spectral data are scaled white noise not coded in the bitstream.
84    INTENSITY_BT2  = 14,    ///< Scalefactor data are intensity stereo positions.
85    INTENSITY_BT   = 15,    ///< Scalefactor data are intensity stereo positions.
86};
87
88#define IS_CODEBOOK_UNSIGNED(x) ((x - 1) & 10)
89
90enum ChannelPosition {
91    AAC_CHANNEL_FRONT = 1,
92    AAC_CHANNEL_SIDE  = 2,
93    AAC_CHANNEL_BACK  = 3,
94    AAC_CHANNEL_LFE   = 4,
95    AAC_CHANNEL_CC    = 5,
96};
97
98/**
99 * The point during decoding at which channel coupling is applied.
100 */
101enum CouplingPoint {
102    BEFORE_TNS,
103    BETWEEN_TNS_AND_IMDCT,
104    AFTER_IMDCT = 3,
105};
106
107/**
108 * Output configuration status
109 */
110enum OCStatus {
111    OC_NONE,        //< Output unconfigured
112    OC_TRIAL_PCE,   //< Output configuration under trial specified by an inband PCE
113    OC_TRIAL_FRAME, //< Output configuration under trial specified by a frame header
114    OC_GLOBAL_HDR,  //< Output configuration set in a global header but not yet locked
115    OC_LOCKED,      //< Output configuration locked in place
116};
117
118/**
119 * Predictor State
120 */
121typedef struct {
122    float cor0;
123    float cor1;
124    float var0;
125    float var1;
126    float r0;
127    float r1;
128} PredictorState;
129
130#define MAX_PREDICTORS 672
131
132#define SCALE_DIV_512    36    ///< scalefactor difference that corresponds to scale difference in 512 times
133#define SCALE_ONE_POS   140    ///< scalefactor index that corresponds to scale=1.0
134#define SCALE_MAX_POS   255    ///< scalefactor index maximum value
135#define SCALE_MAX_DIFF   60    ///< maximum scalefactor difference allowed by standard
136#define SCALE_DIFF_ZERO  60    ///< codebook index corresponding to zero scalefactor indices difference
137
138/**
139 * Individual Channel Stream
140 */
141typedef struct {
142    uint8_t max_sfb;            ///< number of scalefactor bands per group
143    enum WindowSequence window_sequence[2];
144    uint8_t use_kb_window[2];   ///< If set, use Kaiser-Bessel window, otherwise use a sinus window.
145    int num_window_groups;
146    uint8_t group_len[8];
147    const uint16_t *swb_offset; ///< table of offsets to the lowest spectral coefficient of a scalefactor band, sfb, for a particular window
148    const uint8_t *swb_sizes;   ///< table of scalefactor band sizes for a particular window
149    int num_swb;                ///< number of scalefactor window bands
150    int num_windows;
151    int tns_max_bands;
152    int predictor_present;
153    int predictor_initialized;
154    int predictor_reset_group;
155    uint8_t prediction_used[41];
156} IndividualChannelStream;
157
158/**
159 * Temporal Noise Shaping
160 */
161typedef struct {
162    int present;
163    int n_filt[8];
164    int length[8][4];
165    int direction[8][4];
166    int order[8][4];
167    float coef[8][4][TNS_MAX_ORDER];
168} TemporalNoiseShaping;
169
170/**
171 * Dynamic Range Control - decoded from the bitstream but not processed further.
172 */
173typedef struct {
174    int pce_instance_tag;                           ///< Indicates with which program the DRC info is associated.
175    int dyn_rng_sgn[17];                            ///< DRC sign information; 0 - positive, 1 - negative
176    int dyn_rng_ctl[17];                            ///< DRC magnitude information
177    int exclude_mask[MAX_CHANNELS];                 ///< Channels to be excluded from DRC processing.
178    int band_incr;                                  ///< Number of DRC bands greater than 1 having DRC info.
179    int interpolation_scheme;                       ///< Indicates the interpolation scheme used in the SBR QMF domain.
180    int band_top[17];                               ///< Indicates the top of the i-th DRC band in units of 4 spectral lines.
181    int prog_ref_level;                             /**< A reference level for the long-term program audio level for all
182                                                     *   channels combined.
183                                                     */
184} DynamicRangeControl;
185
186typedef struct {
187    int num_pulse;
188    int start;
189    int pos[4];
190    int amp[4];
191} Pulse;
192
193/**
194 * coupling parameters
195 */
196typedef struct {
197    enum CouplingPoint coupling_point;  ///< The point during decoding at which coupling is applied.
198    int num_coupled;       ///< number of target elements
199    enum RawDataBlockType type[8];   ///< Type of channel element to be coupled - SCE or CPE.
200    int id_select[8];      ///< element id
201    int ch_select[8];      /**< [0] shared list of gains; [1] list of gains for right channel;
202                            *   [2] list of gains for left channel; [3] lists of gains for both channels
203                            */
204    float gain[16][120];
205} ChannelCoupling;
206
207/**
208 * Single Channel Element - used for both SCE and LFE elements.
209 */
210typedef struct {
211    IndividualChannelStream ics;
212    TemporalNoiseShaping tns;
213    Pulse pulse;
214    enum BandType band_type[128];             ///< band types
215    int band_type_run_end[120];               ///< band type run end points
216    float sf[120];                            ///< scalefactors
217    int sf_idx[128];                          ///< scalefactor indices (used by encoder)
218    uint8_t zeroes[128];                      ///< band is not coded (used by encoder)
219    DECLARE_ALIGNED(16, float, coeffs)[1024]; ///< coefficients for IMDCT
220    DECLARE_ALIGNED(16, float, saved)[1024];  ///< overlap
221    DECLARE_ALIGNED(16, float, ret)[2048];    ///< PCM output
222    PredictorState predictor_state[MAX_PREDICTORS];
223} SingleChannelElement;
224
225/**
226 * channel element - generic struct for SCE/CPE/CCE/LFE
227 */
228typedef struct {
229    // CPE specific
230    int common_window;        ///< Set if channels share a common 'IndividualChannelStream' in bitstream.
231    int     ms_mode;          ///< Signals mid/side stereo flags coding mode (used by encoder)
232    uint8_t ms_mask[128];     ///< Set if mid/side stereo is used for each scalefactor window band
233    // shared
234    SingleChannelElement ch[2];
235    // CCE specific
236    ChannelCoupling coup;
237    SpectralBandReplication sbr;
238} ChannelElement;
239
240/**
241 * main AAC context
242 */
243typedef struct {
244    AVCodecContext * avccontext;
245
246    MPEG4AudioConfig m4ac;
247
248    int is_saved;                 ///< Set if elements have stored overlap from previous frame.
249    DynamicRangeControl che_drc;
250
251    /**
252     * @defgroup elements Channel element related data.
253     * @{
254     */
255    enum ChannelPosition che_pos[4][MAX_ELEM_ID]; /**< channel element channel mapping with the
256                                                   *   first index as the first 4 raw data block types
257                                                   */
258    ChannelElement * che[4][MAX_ELEM_ID];
259    ChannelElement * tag_che_map[4][MAX_ELEM_ID];
260    int tags_mapped;
261    /** @} */
262
263    /**
264     * @defgroup temporary aligned temporary buffers (We do not want to have these on the stack.)
265     * @{
266     */
267    DECLARE_ALIGNED(16, float, buf_mdct)[1024];
268    /** @} */
269
270    /**
271     * @defgroup tables   Computed / set up during initialization.
272     * @{
273     */
274    FFTContext mdct;
275    FFTContext mdct_small;
276    DSPContext dsp;
277    int random_state;
278    /** @} */
279
280    /**
281     * @defgroup output   Members used for output interleaving.
282     * @{
283     */
284    float *output_data[MAX_CHANNELS];                 ///< Points to each element's 'ret' buffer (PCM output).
285    float add_bias;                                   ///< offset for dsp.float_to_int16
286    float sf_scale;                                   ///< Pre-scale for correct IMDCT and dsp.float_to_int16.
287    int sf_offset;                                    ///< offset into pow2sf_tab as appropriate for dsp.float_to_int16
288    /** @} */
289
290    DECLARE_ALIGNED(16, float, temp)[128];
291
292    enum OCStatus output_configured;
293} AACContext;
294
295#endif /* AVCODEC_AAC_H */
296