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 Libav.
7 *
8 * Libav 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 * Libav 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 Libav; 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#include "fmtconvert.h"
39
40#include <stdint.h>
41
42#define MAX_CHANNELS 64
43#define MAX_ELEM_ID 16
44
45#define TNS_MAX_ORDER 20
46#define MAX_LTP_LONG_SFB 40
47
48enum RawDataBlockType {
49    TYPE_SCE,
50    TYPE_CPE,
51    TYPE_CCE,
52    TYPE_LFE,
53    TYPE_DSE,
54    TYPE_PCE,
55    TYPE_FIL,
56    TYPE_END,
57};
58
59enum ExtensionPayloadID {
60    EXT_FILL,
61    EXT_FILL_DATA,
62    EXT_DATA_ELEMENT,
63    EXT_DYNAMIC_RANGE = 0xb,
64    EXT_SBR_DATA      = 0xd,
65    EXT_SBR_DATA_CRC  = 0xe,
66};
67
68enum WindowSequence {
69    ONLY_LONG_SEQUENCE,
70    LONG_START_SEQUENCE,
71    EIGHT_SHORT_SEQUENCE,
72    LONG_STOP_SEQUENCE,
73};
74
75enum BandType {
76    ZERO_BT        = 0,     ///< Scalefactors and spectral data are all zero.
77    FIRST_PAIR_BT  = 5,     ///< This and later band types encode two values (rather than four) with one code word.
78    ESC_BT         = 11,    ///< Spectral data are coded with an escape sequence.
79    NOISE_BT       = 13,    ///< Spectral data are scaled white noise not coded in the bitstream.
80    INTENSITY_BT2  = 14,    ///< Scalefactor data are intensity stereo positions.
81    INTENSITY_BT   = 15,    ///< Scalefactor data are intensity stereo positions.
82};
83
84#define IS_CODEBOOK_UNSIGNED(x) ((x - 1) & 10)
85
86enum ChannelPosition {
87    AAC_CHANNEL_OFF   = 0,
88    AAC_CHANNEL_FRONT = 1,
89    AAC_CHANNEL_SIDE  = 2,
90    AAC_CHANNEL_BACK  = 3,
91    AAC_CHANNEL_LFE   = 4,
92    AAC_CHANNEL_CC    = 5,
93};
94
95/**
96 * The point during decoding at which channel coupling is applied.
97 */
98enum CouplingPoint {
99    BEFORE_TNS,
100    BETWEEN_TNS_AND_IMDCT,
101    AFTER_IMDCT = 3,
102};
103
104/**
105 * Output configuration status
106 */
107enum OCStatus {
108    OC_NONE,        ///< Output unconfigured
109    OC_TRIAL_PCE,   ///< Output configuration under trial specified by an inband PCE
110    OC_TRIAL_FRAME, ///< Output configuration under trial specified by a frame header
111    OC_GLOBAL_HDR,  ///< Output configuration set in a global header but not yet locked
112    OC_LOCKED,      ///< Output configuration locked in place
113};
114
115/**
116 * Predictor State
117 */
118typedef struct {
119    float cor0;
120    float cor1;
121    float var0;
122    float var1;
123    float r0;
124    float r1;
125} PredictorState;
126
127#define MAX_PREDICTORS 672
128
129#define SCALE_DIV_512    36    ///< scalefactor difference that corresponds to scale difference in 512 times
130#define SCALE_ONE_POS   140    ///< scalefactor index that corresponds to scale=1.0
131#define SCALE_MAX_POS   255    ///< scalefactor index maximum value
132#define SCALE_MAX_DIFF   60    ///< maximum scalefactor difference allowed by standard
133#define SCALE_DIFF_ZERO  60    ///< codebook index corresponding to zero scalefactor indices difference
134#define POW_SF2_ZERO    200    ///< ff_aac_pow2sf_tab index corresponding to pow(2, 0);
135
136/**
137 * Long Term Prediction
138 */
139typedef struct {
140    int8_t present;
141    int16_t lag;
142    float coef;
143    int8_t used[MAX_LTP_LONG_SFB];
144} LongTermPrediction;
145
146/**
147 * Individual Channel Stream
148 */
149typedef struct {
150    uint8_t max_sfb;            ///< number of scalefactor bands per group
151    enum WindowSequence window_sequence[2];
152    uint8_t use_kb_window[2];   ///< If set, use Kaiser-Bessel window, otherwise use a sinus window.
153    int num_window_groups;
154    uint8_t group_len[8];
155    LongTermPrediction ltp;
156    const uint16_t *swb_offset; ///< table of offsets to the lowest spectral coefficient of a scalefactor band, sfb, for a particular window
157    const uint8_t *swb_sizes;   ///< table of scalefactor band sizes for a particular window
158    int num_swb;                ///< number of scalefactor window bands
159    int num_windows;
160    int tns_max_bands;
161    int predictor_present;
162    int predictor_initialized;
163    int predictor_reset_group;
164    uint8_t prediction_used[41];
165} IndividualChannelStream;
166
167/**
168 * Temporal Noise Shaping
169 */
170typedef struct {
171    int present;
172    int n_filt[8];
173    int length[8][4];
174    int direction[8][4];
175    int order[8][4];
176    float coef[8][4][TNS_MAX_ORDER];
177} TemporalNoiseShaping;
178
179/**
180 * Dynamic Range Control - decoded from the bitstream but not processed further.
181 */
182typedef struct {
183    int pce_instance_tag;                           ///< Indicates with which program the DRC info is associated.
184    int dyn_rng_sgn[17];                            ///< DRC sign information; 0 - positive, 1 - negative
185    int dyn_rng_ctl[17];                            ///< DRC magnitude information
186    int exclude_mask[MAX_CHANNELS];                 ///< Channels to be excluded from DRC processing.
187    int band_incr;                                  ///< Number of DRC bands greater than 1 having DRC info.
188    int interpolation_scheme;                       ///< Indicates the interpolation scheme used in the SBR QMF domain.
189    int band_top[17];                               ///< Indicates the top of the i-th DRC band in units of 4 spectral lines.
190    int prog_ref_level;                             /**< A reference level for the long-term program audio level for all
191                                                     *   channels combined.
192                                                     */
193} DynamicRangeControl;
194
195typedef struct {
196    int num_pulse;
197    int start;
198    int pos[4];
199    int amp[4];
200} Pulse;
201
202/**
203 * coupling parameters
204 */
205typedef struct {
206    enum CouplingPoint coupling_point;  ///< The point during decoding at which coupling is applied.
207    int num_coupled;       ///< number of target elements
208    enum RawDataBlockType type[8];   ///< Type of channel element to be coupled - SCE or CPE.
209    int id_select[8];      ///< element id
210    int ch_select[8];      /**< [0] shared list of gains; [1] list of gains for right channel;
211                            *   [2] list of gains for left channel; [3] lists of gains for both channels
212                            */
213    float gain[16][120];
214} ChannelCoupling;
215
216/**
217 * Single Channel Element - used for both SCE and LFE elements.
218 */
219typedef struct {
220    IndividualChannelStream ics;
221    TemporalNoiseShaping tns;
222    Pulse pulse;
223    enum BandType band_type[128];                   ///< band types
224    int band_type_run_end[120];                     ///< band type run end points
225    float sf[120];                                  ///< scalefactors
226    int sf_idx[128];                                ///< scalefactor indices (used by encoder)
227    uint8_t zeroes[128];                            ///< band is not coded (used by encoder)
228    DECLARE_ALIGNED(32, float,   coeffs)[1024];     ///< coefficients for IMDCT
229    DECLARE_ALIGNED(32, float,   saved)[1024];      ///< overlap
230    DECLARE_ALIGNED(32, float,   ret)[2048];        ///< PCM output
231    DECLARE_ALIGNED(16, float,   ltp_state)[3072];  ///< time signal for LTP
232    PredictorState predictor_state[MAX_PREDICTORS];
233} SingleChannelElement;
234
235/**
236 * channel element - generic struct for SCE/CPE/CCE/LFE
237 */
238typedef struct {
239    // CPE specific
240    int common_window;        ///< Set if channels share a common 'IndividualChannelStream' in bitstream.
241    int     ms_mode;          ///< Signals mid/side stereo flags coding mode (used by encoder)
242    uint8_t ms_mask[128];     ///< Set if mid/side stereo is used for each scalefactor window band
243    // shared
244    SingleChannelElement ch[2];
245    // CCE specific
246    ChannelCoupling coup;
247    SpectralBandReplication sbr;
248} ChannelElement;
249
250/**
251 * main AAC context
252 */
253typedef struct {
254    AVCodecContext *avctx;
255    AVFrame frame;
256
257    MPEG4AudioConfig m4ac;
258
259    int is_saved;                 ///< Set if elements have stored overlap from previous frame.
260    DynamicRangeControl che_drc;
261
262    /**
263     * @name Channel element related data
264     * @{
265     */
266    enum ChannelPosition che_pos[4][MAX_ELEM_ID]; /**< channel element channel mapping with the
267                                                   *   first index as the first 4 raw data block types
268                                                   */
269    ChannelElement          *che[4][MAX_ELEM_ID];
270    ChannelElement  *tag_che_map[4][MAX_ELEM_ID];
271    int tags_mapped;
272    /** @} */
273
274    /**
275     * @name temporary aligned temporary buffers
276     * (We do not want to have these on the stack.)
277     * @{
278     */
279    DECLARE_ALIGNED(32, float, buf_mdct)[1024];
280    /** @} */
281
282    /**
283     * @name Computed / set up during initialization
284     * @{
285     */
286    FFTContext mdct;
287    FFTContext mdct_small;
288    FFTContext mdct_ltp;
289    DSPContext dsp;
290    FmtConvertContext fmt_conv;
291    int random_state;
292    /** @} */
293
294    /**
295     * @name Members used for output interleaving
296     * @{
297     */
298    float *output_data[MAX_CHANNELS];                 ///< Points to each element's 'ret' buffer (PCM output).
299    /** @} */
300
301    DECLARE_ALIGNED(32, float, temp)[128];
302
303    enum OCStatus output_configured;
304} AACContext;
305
306#endif /* AVCODEC_AAC_H */
307