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aac.h
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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 "libavutil/float_dsp.h"
34 #include "avcodec.h"
35 #include "dsputil.h"
36 #include "fft.h"
37 #include "mpeg4audio.h"
38 #include "sbr.h"
39 #include "fmtconvert.h"
40 
41 #include <stdint.h>
42 
43 #define MAX_CHANNELS 64
44 #define MAX_ELEM_ID 16
45 
46 #define TNS_MAX_ORDER 20
47 #define MAX_LTP_LONG_SFB 40
48 
58 };
59 
65  EXT_SBR_DATA = 0xd,
67 };
68 
74 };
75 
76 enum BandType {
77  ZERO_BT = 0, ///< Scalefactors and spectral data are all zero.
78  FIRST_PAIR_BT = 5, ///< This and later band types encode two values (rather than four) with one code word.
79  ESC_BT = 11, ///< Spectral data are coded with an escape sequence.
80  NOISE_BT = 13, ///< Spectral data are scaled white noise not coded in the bitstream.
81  INTENSITY_BT2 = 14, ///< Scalefactor data are intensity stereo positions.
82  INTENSITY_BT = 15, ///< Scalefactor data are intensity stereo positions.
83 };
84 
85 #define IS_CODEBOOK_UNSIGNED(x) ((x - 1) & 10)
86 
94 };
95 
96 /**
97  * The point during decoding at which channel coupling is applied.
98  */
103 };
104 
105 /**
106  * Output configuration status
107  */
108 enum OCStatus {
109  OC_NONE, ///< Output unconfigured
110  OC_TRIAL_PCE, ///< Output configuration under trial specified by an inband PCE
111  OC_TRIAL_FRAME, ///< Output configuration under trial specified by a frame header
112  OC_GLOBAL_HDR, ///< Output configuration set in a global header but not yet locked
113  OC_LOCKED, ///< Output configuration locked in place
114 };
115 
116 typedef struct OutputConfiguration {
120  int channels;
121  uint64_t channel_layout;
124 
125 /**
126  * Predictor State
127  */
128 typedef struct PredictorState {
129  float cor0;
130  float cor1;
131  float var0;
132  float var1;
133  float r0;
134  float r1;
136 
137 #define MAX_PREDICTORS 672
138 
139 #define SCALE_DIV_512 36 ///< scalefactor difference that corresponds to scale difference in 512 times
140 #define SCALE_ONE_POS 140 ///< scalefactor index that corresponds to scale=1.0
141 #define SCALE_MAX_POS 255 ///< scalefactor index maximum value
142 #define SCALE_MAX_DIFF 60 ///< maximum scalefactor difference allowed by standard
143 #define SCALE_DIFF_ZERO 60 ///< codebook index corresponding to zero scalefactor indices difference
144 
145 /**
146  * Long Term Prediction
147  */
148 typedef struct LongTermPrediction {
149  int8_t present;
150  int16_t lag;
151  float coef;
154 
155 /**
156  * Individual Channel Stream
157  */
158 typedef struct IndividualChannelStream {
159  uint8_t max_sfb; ///< number of scalefactor bands per group
161  uint8_t use_kb_window[2]; ///< If set, use Kaiser-Bessel window, otherwise use a sinus window.
165  const uint16_t *swb_offset; ///< table of offsets to the lowest spectral coefficient of a scalefactor band, sfb, for a particular window
166  const uint8_t *swb_sizes; ///< table of scalefactor band sizes for a particular window
167  int num_swb; ///< number of scalefactor window bands
175 
176 /**
177  * Temporal Noise Shaping
178  */
179 typedef struct TemporalNoiseShaping {
180  int present;
181  int n_filt[8];
182  int length[8][4];
183  int direction[8][4];
184  int order[8][4];
185  float coef[8][4][TNS_MAX_ORDER];
187 
188 /**
189  * Dynamic Range Control - decoded from the bitstream but not processed further.
190  */
191 typedef struct DynamicRangeControl {
192  int pce_instance_tag; ///< Indicates with which program the DRC info is associated.
193  int dyn_rng_sgn[17]; ///< DRC sign information; 0 - positive, 1 - negative
194  int dyn_rng_ctl[17]; ///< DRC magnitude information
195  int exclude_mask[MAX_CHANNELS]; ///< Channels to be excluded from DRC processing.
196  int band_incr; ///< Number of DRC bands greater than 1 having DRC info.
197  int interpolation_scheme; ///< Indicates the interpolation scheme used in the SBR QMF domain.
198  int band_top[17]; ///< Indicates the top of the i-th DRC band in units of 4 spectral lines.
199  int prog_ref_level; /**< A reference level for the long-term program audio level for all
200  * channels combined.
201  */
203 
204 typedef struct Pulse {
206  int start;
207  int pos[4];
208  int amp[4];
209 } Pulse;
210 
211 /**
212  * coupling parameters
213  */
214 typedef struct ChannelCoupling {
215  enum CouplingPoint coupling_point; ///< The point during decoding at which coupling is applied.
216  int num_coupled; ///< number of target elements
217  enum RawDataBlockType type[8]; ///< Type of channel element to be coupled - SCE or CPE.
218  int id_select[8]; ///< element id
219  int ch_select[8]; /**< [0] shared list of gains; [1] list of gains for right channel;
220  * [2] list of gains for left channel; [3] lists of gains for both channels
221  */
222  float gain[16][120];
224 
225 /**
226  * Single Channel Element - used for both SCE and LFE elements.
227  */
228 typedef struct SingleChannelElement {
232  enum BandType band_type[128]; ///< band types
233  int band_type_run_end[120]; ///< band type run end points
234  float sf[120]; ///< scalefactors
235  int sf_idx[128]; ///< scalefactor indices (used by encoder)
236  uint8_t zeroes[128]; ///< band is not coded (used by encoder)
237  DECLARE_ALIGNED(32, float, coeffs)[1024]; ///< coefficients for IMDCT
238  DECLARE_ALIGNED(32, float, saved)[1024]; ///< overlap
239  DECLARE_ALIGNED(32, float, ret_buf)[2048]; ///< PCM output buffer
240  DECLARE_ALIGNED(16, float, ltp_state)[3072]; ///< time signal for LTP
242  float *ret; ///< PCM output
244 
245 /**
246  * channel element - generic struct for SCE/CPE/CCE/LFE
247  */
248 typedef struct ChannelElement {
249  // CPE specific
250  int common_window; ///< Set if channels share a common 'IndividualChannelStream' in bitstream.
251  int ms_mode; ///< Signals mid/side stereo flags coding mode (used by encoder)
252  uint8_t ms_mask[128]; ///< Set if mid/side stereo is used for each scalefactor window band
253  // shared
255  // CCE specific
259 
260 /**
261  * main AAC context
262  */
263 typedef struct AACContext {
264  AVClass *class;
267 
268  int is_saved; ///< Set if elements have stored overlap from previous frame.
270 
271  /**
272  * @name Channel element related data
273  * @{
274  */
278  /** @} */
279 
280  /**
281  * @name temporary aligned temporary buffers
282  * (We do not want to have these on the stack.)
283  * @{
284  */
285  DECLARE_ALIGNED(32, float, buf_mdct)[1024];
286  /** @} */
287 
288  /**
289  * @name Computed / set up during initialization
290  * @{
291  */
299  /** @} */
300 
301  /**
302  * @name Members used for output
303  * @{
304  */
305  SingleChannelElement *output_element[MAX_CHANNELS]; ///< Points to each SingleChannelElement
306  /** @} */
307 
308 
309  /**
310  * @name Japanese DTV specific extension
311  * @{
312  */
313  int force_dmono_mode;///< 0->not dmono, 1->use first channel, 2->use second channel
314  int dmono_mode; ///< 0->not dmono, 1->use first channel, 2->use second channel
315  /** @} */
316 
317  DECLARE_ALIGNED(32, float, temp)[128];
318 
321 } AACContext;
322 
323 #endif /* AVCODEC_AAC_H */