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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 "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 
57 };
58 
64  EXT_SBR_DATA = 0xd,
66 };
67 
73 };
74 
75 enum 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 
93 };
94 
95 /**
96  * The point during decoding at which channel coupling is applied.
97  */
102 };
103 
104 /**
105  * Output configuration status
106  */
107 enum 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 typedef struct OutputConfiguration {
119  int channels;
120  uint64_t channel_layout;
123 
124 /**
125  * Predictor State
126  */
127 typedef struct PredictorState {
128  float cor0;
129  float cor1;
130  float var0;
131  float var1;
132  float r0;
133  float r1;
135 
136 #define MAX_PREDICTORS 672
137 
138 #define SCALE_DIV_512 36 ///< scalefactor difference that corresponds to scale difference in 512 times
139 #define SCALE_ONE_POS 140 ///< scalefactor index that corresponds to scale=1.0
140 #define SCALE_MAX_POS 255 ///< scalefactor index maximum value
141 #define SCALE_MAX_DIFF 60 ///< maximum scalefactor difference allowed by standard
142 #define SCALE_DIFF_ZERO 60 ///< codebook index corresponding to zero scalefactor indices difference
143 
144 /**
145  * Long Term Prediction
146  */
147 typedef struct LongTermPrediction {
148  int8_t present;
149  int16_t lag;
150  float coef;
153 
154 /**
155  * Individual Channel Stream
156  */
157 typedef struct IndividualChannelStream {
158  uint8_t max_sfb; ///< number of scalefactor bands per group
160  uint8_t use_kb_window[2]; ///< If set, use Kaiser-Bessel window, otherwise use a sine window.
164  const uint16_t *swb_offset; ///< table of offsets to the lowest spectral coefficient of a scalefactor band, sfb, for a particular window
165  const uint8_t *swb_sizes; ///< table of scalefactor band sizes for a particular window
166  int num_swb; ///< number of scalefactor window bands
174 
175 /**
176  * Temporal Noise Shaping
177  */
178 typedef struct TemporalNoiseShaping {
179  int present;
180  int n_filt[8];
181  int length[8][4];
182  int direction[8][4];
183  int order[8][4];
184  float coef[8][4][TNS_MAX_ORDER];
186 
187 /**
188  * Dynamic Range Control - decoded from the bitstream but not processed further.
189  */
190 typedef struct DynamicRangeControl {
191  int pce_instance_tag; ///< Indicates with which program the DRC info is associated.
192  int dyn_rng_sgn[17]; ///< DRC sign information; 0 - positive, 1 - negative
193  int dyn_rng_ctl[17]; ///< DRC magnitude information
194  int exclude_mask[MAX_CHANNELS]; ///< Channels to be excluded from DRC processing.
195  int band_incr; ///< Number of DRC bands greater than 1 having DRC info.
196  int interpolation_scheme; ///< Indicates the interpolation scheme used in the SBR QMF domain.
197  int band_top[17]; ///< Indicates the top of the i-th DRC band in units of 4 spectral lines.
198  int prog_ref_level; /**< A reference level for the long-term program audio level for all
199  * channels combined.
200  */
202 
203 typedef struct Pulse {
205  int start;
206  int pos[4];
207  int amp[4];
208 } Pulse;
209 
210 /**
211  * coupling parameters
212  */
213 typedef struct ChannelCoupling {
214  enum CouplingPoint coupling_point; ///< The point during decoding at which coupling is applied.
215  int num_coupled; ///< number of target elements
216  enum RawDataBlockType type[8]; ///< Type of channel element to be coupled - SCE or CPE.
217  int id_select[8]; ///< element id
218  int ch_select[8]; /**< [0] shared list of gains; [1] list of gains for right channel;
219  * [2] list of gains for left channel; [3] lists of gains for both channels
220  */
221  float gain[16][120];
223 
224 /**
225  * Single Channel Element - used for both SCE and LFE elements.
226  */
227 typedef struct SingleChannelElement {
231  enum BandType band_type[128]; ///< band types
232  int band_type_run_end[120]; ///< band type run end points
233  float sf[120]; ///< scalefactors
234  int sf_idx[128]; ///< scalefactor indices (used by encoder)
235  uint8_t zeroes[128]; ///< band is not coded (used by encoder)
236  DECLARE_ALIGNED(32, float, coeffs)[1024]; ///< coefficients for IMDCT
237  DECLARE_ALIGNED(32, float, saved)[1536]; ///< overlap
238  DECLARE_ALIGNED(32, float, ret_buf)[2048]; ///< PCM output buffer
239  DECLARE_ALIGNED(16, float, ltp_state)[3072]; ///< time signal for LTP
241  float *ret; ///< PCM output
243 
244 /**
245  * channel element - generic struct for SCE/CPE/CCE/LFE
246  */
247 typedef struct ChannelElement {
248  // CPE specific
249  int common_window; ///< Set if channels share a common 'IndividualChannelStream' in bitstream.
250  int ms_mode; ///< Signals mid/side stereo flags coding mode (used by encoder)
251  uint8_t ms_mask[128]; ///< Set if mid/side stereo is used for each scalefactor window band
252  // shared
254  // CCE specific
258 
259 /**
260  * main AAC context
261  */
262 struct AACContext {
263  AVClass *class;
266 
267  int is_saved; ///< Set if elements have stored overlap from previous frame.
269 
270  /**
271  * @name Channel element related data
272  * @{
273  */
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 
322  /* aacdec functions pointers */
325  void (*apply_tns)(float coef[1024], TemporalNoiseShaping *tns,
326  IndividualChannelStream *ics, int decode);
328  float *in, IndividualChannelStream *ics);
330 
331 };
332 
334 
335 #endif /* AVCODEC_AAC_H */