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 )
6 * This file is part of FFmpeg.
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.
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.
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
24 * @file libavcodec/aac.h
25 * AAC definitions and structures
26 * @author Oded Shimon ( ods15 ods15 dyndns org )
27 * @author Maxim Gavrilov ( maxim.gavrilov gmail com )
35 #include "mpeg4audio.h"
39 #define AAC_INIT_VLC_STATIC(num, size) \
40 INIT_VLC_STATIC(&vlc_spectral[num], 6, ff_aac_spectral_sizes[num], \
41 ff_aac_spectral_bits[num], sizeof( ff_aac_spectral_bits[num][0]), sizeof( ff_aac_spectral_bits[num][0]), \
42 ff_aac_spectral_codes[num], sizeof(ff_aac_spectral_codes[num][0]), sizeof(ff_aac_spectral_codes[num][0]), \
45 #define MAX_CHANNELS 64
46 #define MAX_ELEM_ID 16
48 #define TNS_MAX_ORDER 20
50 enum RawDataBlockType
{
61 enum ExtensionPayloadID
{
65 EXT_DYNAMIC_RANGE
= 0xb,
67 EXT_SBR_DATA_CRC
= 0xe,
78 ZERO_BT
= 0, ///< Scalefactors and spectral data are all zero.
79 FIRST_PAIR_BT
= 5, ///< This and later band types encode two values (rather than four) with one code word.
80 ESC_BT
= 11, ///< Spectral data are coded with an escape sequence.
81 NOISE_BT
= 13, ///< Spectral data are scaled white noise not coded in the bitstream.
82 INTENSITY_BT2
= 14, ///< Scalefactor data are intensity stereo positions.
83 INTENSITY_BT
= 15, ///< Scalefactor data are intensity stereo positions.
86 #define IS_CODEBOOK_UNSIGNED(x) ((x - 1) & 10)
88 enum ChannelPosition
{
89 AAC_CHANNEL_FRONT
= 1,
97 * The point during decoding at which channel coupling is applied.
101 BETWEEN_TNS_AND_IMDCT
,
117 #define MAX_PREDICTORS 672
120 * Individual Channel Stream
123 uint8_t max_sfb
; ///< number of scalefactor bands per group
124 enum WindowSequence window_sequence
[2];
125 uint8_t use_kb_window
[2]; ///< If set, use Kaiser-Bessel window, otherwise use a sinus window.
126 int num_window_groups
;
127 uint8_t group_len
[8];
128 const uint16_t *swb_offset
; ///< table of offsets to the lowest spectral coefficient of a scalefactor band, sfb, for a particular window
129 int num_swb
; ///< number of scalefactor window bands
132 int predictor_present
;
133 int predictor_initialized
;
134 int predictor_reset_group
;
135 uint8_t prediction_used
[41];
136 } IndividualChannelStream
;
139 * Temporal Noise Shaping
147 float coef
[8][4][TNS_MAX_ORDER
];
148 } TemporalNoiseShaping
;
151 * Dynamic Range Control - decoded from the bitstream but not processed further.
154 int pce_instance_tag
; ///< Indicates with which program the DRC info is associated.
155 int dyn_rng_sgn
[17]; ///< DRC sign information; 0 - positive, 1 - negative
156 int dyn_rng_ctl
[17]; ///< DRC magnitude information
157 int exclude_mask
[MAX_CHANNELS
]; ///< Channels to be excluded from DRC processing.
158 int band_incr
; ///< Number of DRC bands greater than 1 having DRC info.
159 int interpolation_scheme
; ///< Indicates the interpolation scheme used in the SBR QMF domain.
160 int band_top
[17]; ///< Indicates the top of the i-th DRC band in units of 4 spectral lines.
161 int prog_ref_level
; /**< A reference level for the long-term program audio level for all
164 } DynamicRangeControl
;
173 * coupling parameters
176 enum CouplingPoint coupling_point
; ///< The point during decoding at which coupling is applied.
177 int num_coupled
; ///< number of target elements
178 enum RawDataBlockType type
[8]; ///< Type of channel element to be coupled - SCE or CPE.
179 int id_select
[8]; ///< element id
180 int ch_select
[8]; /**< [0] shared list of gains; [1] list of gains for right channel;
181 * [2] list of gains for left channel; [3] lists of gains for both channels
187 * Single Channel Element - used for both SCE and LFE elements.
190 IndividualChannelStream ics
;
191 TemporalNoiseShaping tns
;
192 enum BandType band_type
[120]; ///< band types
193 int band_type_run_end
[120]; ///< band type run end points
194 float sf
[120]; ///< scalefactors
195 DECLARE_ALIGNED_16(float, coeffs
[1024]); ///< coefficients for IMDCT
196 DECLARE_ALIGNED_16(float, saved
[512]); ///< overlap
197 DECLARE_ALIGNED_16(float, ret
[1024]); ///< PCM output
198 PredictorState predictor_state
[MAX_PREDICTORS
];
199 } SingleChannelElement
;
202 * channel element - generic struct for SCE/CPE/CCE/LFE
206 uint8_t ms_mask
[120]; ///< Set if mid/side stereo is used for each scalefactor window band
208 SingleChannelElement ch
[2];
210 ChannelCoupling coup
;
217 AVCodecContext
* avccontext
;
219 MPEG4AudioConfig m4ac
;
221 int is_saved
; ///< Set if elements have stored overlap from previous frame.
222 DynamicRangeControl che_drc
;
225 * @defgroup elements Channel element related data.
228 enum ChannelPosition che_pos
[4][MAX_ELEM_ID
]; /**< channel element channel mapping with the
229 * first index as the first 4 raw data block types
231 ChannelElement
* che
[4][MAX_ELEM_ID
];
232 ChannelElement
* tag_che_map
[4][MAX_ELEM_ID
];
237 * @defgroup temporary aligned temporary buffers (We do not want to have these on the stack.)
240 DECLARE_ALIGNED_16(float, buf_mdct
[1024]);
244 * @defgroup tables Computed / set up during initialization.
248 MDCTContext mdct_small
;
254 * @defgroup output Members used for output interleaving.
257 float *output_data
[MAX_CHANNELS
]; ///< Points to each element's 'ret' buffer (PCM output).
258 float add_bias
; ///< offset for dsp.float_to_int16
259 float sf_scale
; ///< Pre-scale for correct IMDCT and dsp.float_to_int16.
260 int sf_offset
; ///< offset into pow2sf_tab as appropriate for dsp.float_to_int16
263 DECLARE_ALIGNED(16, float, temp
[128]);
266 #endif /* AVCODEC_AAC_H */