libavcodec/aacdec.c File Reference

AAC decoder. More...

#include "libavutil/float_dsp.h"
#include "libavutil/opt.h"
#include "avcodec.h"
#include "internal.h"
#include "get_bits.h"
#include "fft.h"
#include "fmtconvert.h"
#include "lpc.h"
#include "kbdwin.h"
#include "sinewin.h"
#include "aac.h"
#include "aactab.h"
#include "aacdectab.h"
#include "cbrt_tablegen.h"
#include "sbr.h"
#include "aacsbr.h"
#include "mpeg4audio.h"
#include "aacadtsdec.h"
#include "libavutil/intfloat.h"
#include <assert.h>
#include <errno.h>
#include <math.h>
#include <string.h>

Include dependency graph for libavcodec/aacdec.c:

Go to the source code of this file.

Data Structures
struct	elem_to_channel
struct	LATMContext

Macros
#define	overread_err   "Input buffer exhausted before END element found\n"
#define	AAC_INIT_VLC_STATIC(num, size)
#define	LOAS_SYNC_WORD   0x2b7
	11 bits LOAS sync word More...
#define	AACDEC_FLAGS   AV_OPT_FLAG_DECODING_PARAM | AV_OPT_FLAG_AUDIO_PARAM
	AVOptions for Japanese DTV specific extensions (ADTS only) More...

Functions
static int	output_configure (AACContext *ac, uint8_t layout_map[MAX_ELEM_ID *4][3], int tags, enum OCStatus oc_type, int get_new_frame)
	Configure output channel order based on the current program configuration element. More...
static int	count_channels (uint8_t(*layout)[3], int tags)
static av_cold int	che_configure (AACContext *ac, enum ChannelPosition che_pos, int type, int id, int *channels)
	Check for the channel element in the current channel position configuration. More...
static int	frame_configure_elements (AVCodecContext *avctx)
static int	assign_pair (struct elem_to_channel e2c_vec[MAX_ELEM_ID], uint8_t(*layout_map)[3], int offset, uint64_t left, uint64_t right, int pos)
static int	count_paired_channels (uint8_t(*layout_map)[3], int tags, int pos, int *current)
static uint64_t	sniff_channel_order (uint8_t(*layout_map)[3], int tags)
static void	push_output_configuration (AACContext *ac)
	Save current output configuration if and only if it has been locked. More...
static void	pop_output_configuration (AACContext *ac)
	Restore the previous output configuration if and only if the current configuration is unlocked. More...
static void	flush (AVCodecContext *avctx)
static int	set_default_channel_config (AVCodecContext *avctx, uint8_t(*layout_map)[3], int *tags, int channel_config)
	Set up channel positions based on a default channel configuration as specified in table 1.17. More...
static ChannelElement *	get_che (AACContext *ac, int type, int elem_id)
static void	decode_channel_map (uint8_t layout_map[][3], enum ChannelPosition type, GetBitContext *gb, int n)
	Decode an array of 4 bit element IDs, optionally interleaved with a stereo/mono switching bit. More...
static int	decode_pce (AVCodecContext *avctx, MPEG4AudioConfig *m4ac, uint8_t(*layout_map)[3], GetBitContext *gb)
	Decode program configuration element; reference: table 4.2. More...
static int	decode_ga_specific_config (AACContext *ac, AVCodecContext *avctx, GetBitContext *gb, MPEG4AudioConfig *m4ac, int channel_config)
	Decode GA "General Audio" specific configuration; reference: table 4.1. More...
static int	decode_audio_specific_config (AACContext *ac, AVCodecContext *avctx, MPEG4AudioConfig *m4ac, const uint8_t *data, int bit_size, int sync_extension)
	Decode audio specific configuration; reference: table 1.13. More...
static av_always_inline int	lcg_random (unsigned previous_val)
	linear congruential pseudorandom number generator More...
static av_always_inline void	reset_predict_state (PredictorState *ps)
static void	reset_all_predictors (PredictorState *ps)
static int	sample_rate_idx (int rate)
static void	reset_predictor_group (PredictorState *ps, int group_num)
static void	aacdec_init (AACContext *ac)
static av_cold int	aac_decode_init (AVCodecContext *avctx)
static int	skip_data_stream_element (AACContext *ac, GetBitContext *gb)
	Skip data_stream_element; reference: table 4.10. More...
static int	decode_prediction (AACContext *ac, IndividualChannelStream *ics, GetBitContext *gb)
static void	decode_ltp (LongTermPrediction *ltp, GetBitContext *gb, uint8_t max_sfb)
	Decode Long Term Prediction data; reference: table 4.xx. More...
static int	decode_ics_info (AACContext *ac, IndividualChannelStream *ics, GetBitContext *gb)
	Decode Individual Channel Stream info; reference: table 4.6. More...
static int	decode_band_types (AACContext *ac, enum BandType band_type[120], int band_type_run_end[120], GetBitContext *gb, IndividualChannelStream *ics)
	Decode band types (section_data payload); reference: table 4.46. More...
static int	decode_scalefactors (AACContext *ac, float sf[120], GetBitContext *gb, unsigned int global_gain, IndividualChannelStream *ics, enum BandType band_type[120], int band_type_run_end[120])
	Decode scalefactors; reference: table 4.47. More...
static int	decode_pulses (Pulse *pulse, GetBitContext *gb, const uint16_t *swb_offset, int num_swb)
	Decode pulse data; reference: table 4.7. More...
static int	decode_tns (AACContext *ac, TemporalNoiseShaping *tns, GetBitContext *gb, const IndividualChannelStream *ics)
	Decode Temporal Noise Shaping data; reference: table 4.48. More...
static void	decode_mid_side_stereo (ChannelElement *cpe, GetBitContext *gb, int ms_present)
	Decode Mid/Side data; reference: table 4.54. More...
static float *	VMUL2 (float *dst, const float *v, unsigned idx, const float *scale)
static float *	VMUL4 (float *dst, const float *v, unsigned idx, const float *scale)
static float *	VMUL2S (float *dst, const float *v, unsigned idx, unsigned sign, const float *scale)
static float *	VMUL4S (float *dst, const float *v, unsigned idx, unsigned sign, const float *scale)
static int	decode_spectrum_and_dequant (AACContext *ac, float coef[1024], GetBitContext *gb, const float sf[120], int pulse_present, const Pulse *pulse, const IndividualChannelStream *ics, enum BandType band_type[120])
	Decode spectral data; reference: table 4.50. More...
static av_always_inline float	flt16_round (float pf)
static av_always_inline float	flt16_even (float pf)
static av_always_inline float	flt16_trunc (float pf)
static av_always_inline void	predict (PredictorState *ps, float *coef, int output_enable)
static void	apply_prediction (AACContext *ac, SingleChannelElement *sce)
	Apply AAC-Main style frequency domain prediction. More...
static int	decode_ics (AACContext *ac, SingleChannelElement *sce, GetBitContext *gb, int common_window, int scale_flag)
	Decode an individual_channel_stream payload; reference: table 4.44. More...
static void	apply_mid_side_stereo (AACContext *ac, ChannelElement *cpe)
	Mid/Side stereo decoding; reference: 4.6.8.1.3. More...
static void	apply_intensity_stereo (AACContext *ac, ChannelElement *cpe, int ms_present)
	intensity stereo decoding; reference: 4.6.8.2.3 More...
static int	decode_cpe (AACContext *ac, GetBitContext *gb, ChannelElement *cpe)
	Decode a channel_pair_element; reference: table 4.4. More...
static int	decode_cce (AACContext *ac, GetBitContext *gb, ChannelElement *che)
	Decode coupling_channel_element; reference: table 4.8. More...
static int	decode_drc_channel_exclusions (DynamicRangeControl *che_drc, GetBitContext *gb)
	Parse whether channels are to be excluded from Dynamic Range Compression; reference: table 4.53. More...
static int	decode_dynamic_range (DynamicRangeControl *che_drc, GetBitContext *gb)
	Decode dynamic range information; reference: table 4.52. More...
static int	decode_fill (AACContext *ac, GetBitContext *gb, int len)
static int	decode_extension_payload (AACContext *ac, GetBitContext *gb, int cnt, ChannelElement *che, enum RawDataBlockType elem_type)
	Decode extension data (incomplete); reference: table 4.51. More...
static void	apply_tns (float coef[1024], TemporalNoiseShaping *tns, IndividualChannelStream *ics, int decode)
	Decode Temporal Noise Shaping filter coefficients and apply all-pole filters; reference: 4.6.9.3. More...
static void	windowing_and_mdct_ltp (AACContext *ac, float *out, float *in, IndividualChannelStream *ics)
	Apply windowing and MDCT to obtain the spectral coefficient from the predicted sample by LTP. More...
static void	apply_ltp (AACContext *ac, SingleChannelElement *sce)
	Apply the long term prediction. More...
static void	update_ltp (AACContext *ac, SingleChannelElement *sce)
	Update the LTP buffer for next frame. More...
static void	imdct_and_windowing (AACContext *ac, SingleChannelElement *sce)
	Conduct IMDCT and windowing. More...
static void	apply_dependent_coupling (AACContext *ac, SingleChannelElement *target, ChannelElement *cce, int index)
	Apply dependent channel coupling (applied before IMDCT). More...
static void	apply_independent_coupling (AACContext *ac, SingleChannelElement *target, ChannelElement *cce, int index)
	Apply independent channel coupling (applied after IMDCT). More...
static void	apply_channel_coupling (AACContext *ac, ChannelElement *cc, enum RawDataBlockType type, int elem_id, enum CouplingPoint coupling_point, void(*apply_coupling_method)(AACContext *ac, SingleChannelElement *target, ChannelElement *cce, int index))
	channel coupling transformation interface More...
static void	spectral_to_sample (AACContext *ac)
	Convert spectral data to float samples, applying all supported tools as appropriate. More...
static int	parse_adts_frame_header (AACContext *ac, GetBitContext *gb)
static int	aac_decode_frame_int (AVCodecContext *avctx, void *data, int *got_frame_ptr, GetBitContext *gb, AVPacket *avpkt)
static int	aac_decode_frame (AVCodecContext *avctx, void *data, int *got_frame_ptr, AVPacket *avpkt)
static av_cold int	aac_decode_close (AVCodecContext *avctx)
static uint32_t	latm_get_value (GetBitContext *b)
static int	latm_decode_audio_specific_config (struct LATMContext *latmctx, GetBitContext *gb, int asclen)
static int	read_stream_mux_config (struct LATMContext *latmctx, GetBitContext *gb)
static int	read_payload_length_info (struct LATMContext *ctx, GetBitContext *gb)
static int	read_audio_mux_element (struct LATMContext *latmctx, GetBitContext *gb)
static int	latm_decode_frame (AVCodecContext *avctx, void *out, int *got_frame_ptr, AVPacket *avpkt)
static av_cold int	latm_decode_init (AVCodecContext *avctx)

Variables
static VLC	vlc_scalefactors
static VLC	vlc_spectral [11]
static const float	cce_scale []
static const AVOption	options []
static const AVClass	aac_decoder_class
AVCodec	ff_aac_decoder
AVCodec	ff_aac_latm_decoder

Detailed Description

AAC decoder.

Author

Oded Shimon ( ods15 ods15 dyndns org )

Maxim Gavrilov ( maxim.gavrilov gmail com )

Definition in file libavcodec/aacdec.c.

Macro Definition Documentation

#define AAC_INIT_VLC_STATIC	(		num,
			size
	)

Value:

INIT_VLC_STATIC(&vlc_spectral[num], 8, ff_aac_spectral_sizes[num], \
         ff_aac_spectral_bits[num], sizeof( ff_aac_spectral_bits[num][0]), sizeof( ff_aac_spectral_bits[num][0]), \
        ff_aac_spectral_codes[num], sizeof(ff_aac_spectral_codes[num][0]), sizeof(ff_aac_spectral_codes[num][0]), \
        size);

Definition at line 875 of file libavcodec/aacdec.c.

Referenced by aac_decode_init().

#define AACDEC_FLAGS   AV_OPT_FLAG_DECODING_PARAM | AV_OPT_FLAG_AUDIO_PARAM

AVOptions for Japanese DTV specific extensions (ADTS only)

Definition at line 3001 of file libavcodec/aacdec.c.

#define LOAS_SYNC_WORD   0x2b7

11 bits LOAS sync word

Definition at line 2717 of file libavcodec/aacdec.c.

Referenced by latm_decode_frame().

#define overread_err   "Input buffer exhausted before END element found\n"

Definition at line 121 of file libavcodec/aacdec.c.

Referenced by aac_decode_frame_int(), decode_band_types(), decode_pce(), and skip_data_stream_element().

Function Documentation

static av_cold int aac_decode_close ( AVCodecContext *  avctx )

static

Definition at line 2697 of file libavcodec/aacdec.c.

static int aac_decode_frame ( AVCodecContext *  avctx, void *  data, int *  got_frame_ptr, AVPacket *  avpkt  )

static

Definition at line 2639 of file libavcodec/aacdec.c.

static int aac_decode_frame_int ( AVCodecContext *  avctx, void *  data, int *  got_frame_ptr, GetBitContext *  gb, AVPacket *  avpkt  )

static

Definition at line 2479 of file libavcodec/aacdec.c.

Referenced by aac_decode_frame(), and latm_decode_frame().

static av_cold int aac_decode_init ( AVCodecContext *  avctx )

static

Definition at line 883 of file libavcodec/aacdec.c.

Referenced by latm_decode_init().

static void aacdec_init ( AACContext *  ac )

static

Definition at line 2987 of file libavcodec/aacdec.c.

Referenced by aac_decode_init().

static void apply_channel_coupling ( AACContext *  ac, ChannelElement *  cc, enum RawDataBlockType  type, int  elem_id, enum CouplingPoint  coupling_point, void(*)(AACContext *ac, SingleChannelElement *target, ChannelElement *cce, int index)  apply_coupling_method  )

static

channel coupling transformation interface

Parameters

apply_coupling_method

pointer to (in)dependent coupling function

Definition at line 2345 of file libavcodec/aacdec.c.

Referenced by spectral_to_sample().

static void apply_dependent_coupling ( AACContext *  ac, SingleChannelElement *  target, ChannelElement *  cce, int  index  )

static

Apply dependent channel coupling (applied before IMDCT).

Parameters

index

index into coupling gain array

Definition at line 2290 of file libavcodec/aacdec.c.

Referenced by spectral_to_sample().

static void apply_independent_coupling ( AACContext *  ac, SingleChannelElement *  target, ChannelElement *  cce, int  index  )

static

Apply independent channel coupling (applied after IMDCT).

Parameters

index

index into coupling gain array

Definition at line 2326 of file libavcodec/aacdec.c.

Referenced by spectral_to_sample().

static void apply_intensity_stereo ( AACContext *  ac, ChannelElement *  cpe, int  ms_present  )

static

intensity stereo decoding; reference: 4.6.8.2.3

Parameters

ms_present

Indicates mid/side stereo presence. [0] mask is all 0s; [1] mask is decoded from bitstream; [2] mask is all 1s; [3] reserved for scalable AAC

Definition at line 1763 of file libavcodec/aacdec.c.

Referenced by decode_cpe().

static void apply_ltp ( AACContext *  ac, SingleChannelElement *  sce  )

static

Apply the long term prediction.

Definition at line 2158 of file libavcodec/aacdec.c.

Referenced by aacdec_init().

static void apply_mid_side_stereo ( AACContext *  ac, ChannelElement *  cpe  )

static

Mid/Side stereo decoding; reference: 4.6.8.1.3.

Definition at line 1733 of file libavcodec/aacdec.c.

Referenced by decode_cpe().

static void apply_prediction ( AACContext *  ac, SingleChannelElement *  sce  )

static

Apply AAC-Main style frequency domain prediction.

Definition at line 1645 of file libavcodec/aacdec.c.

Referenced by decode_cpe(), and decode_ics().

static void apply_tns ( float  coef[1024], TemporalNoiseShaping *  tns, IndividualChannelStream *  ics, int  decode  )

static

Decode Temporal Noise Shaping filter coefficients and apply all-pole filters; reference: 4.6.9.3.

Parameters

decode	1 if tool is used normally, 0 if tool is used in LTP.
coef	spectral coefficients

Definition at line 2076 of file libavcodec/aacdec.c.

Referenced by aacdec_init().

static int assign_pair ( struct elem_to_channel  e2c_vec[MAX_ELEM_ID], uint8_t(*)  layout_map[3], int  offset, uint64_t  left, uint64_t  right, int  pos  )

static

Definition at line 214 of file libavcodec/aacdec.c.

Referenced by sniff_channel_order().

static av_cold int che_configure ( AACContext *  ac, enum ChannelPosition  che_pos, int  type, int  id, int *  channels  )

static

Check for the channel element in the current channel position configuration.

If it exists, make sure the appropriate element is allocated and map the channel order to match the internal FFmpeg channel layout.

Parameters

che_pos	current channel position configuration
type	channel element type
id	channel element id
channels	count of the number of channels in the configuration

Returns

Returns error status. 0 - OK, !0 - error

Definition at line 147 of file libavcodec/aacdec.c.

Referenced by output_configure().

static int count_channels ( uint8_t(*)  layout[3], int  tags  )

static

Definition at line 123 of file libavcodec/aacdec.c.

Referenced by decode_ga_specific_config().

static int count_paired_channels ( uint8_t(*)  layout_map[3], int  tags, int  pos, int *  current  )

static

Definition at line 234 of file libavcodec/aacdec.c.

Referenced by sniff_channel_order().

static int decode_audio_specific_config ( AACContext *  ac, AVCodecContext *  avctx, MPEG4AudioConfig *  m4ac, const uint8_t *  data, int  bit_size, int  sync_extension  )

static

Decode audio specific configuration; reference: table 1.13.

Parameters

ac	pointer to AACContext, may be null
avctx	pointer to AVCCodecContext, used for logging
m4ac	pointer to MPEG4AudioConfig, used for parsing
data	pointer to buffer holding an audio specific config
bit_size	size of audio specific config or data in bits
sync_extension	look for an appended sync extension

Returns

Returns error status or number of consumed bits. <0 - error

Definition at line 775 of file libavcodec/aacdec.c.

Referenced by aac_decode_frame(), aac_decode_init(), latm_decode_audio_specific_config(), and latm_decode_frame().

static int decode_band_types ( AACContext *  ac, enum BandType  band_type[120], int  band_type_run_end[120], GetBitContext *  gb, IndividualChannelStream *  ics  )

static

Decode band types (section_data payload); reference: table 4.46.

Parameters

band_type	array of the used band type
band_type_run_end	array of the last scalefactor band of a band type run

Returns

Returns error status. 0 - OK, !0 - error

Definition at line 1101 of file libavcodec/aacdec.c.

Referenced by decode_ics().

static int decode_cce ( AACContext *  ac, GetBitContext *  gb, ChannelElement *  che  )

static

Decode coupling_channel_element; reference: table 4.8.

Returns

Returns error status. 0 - OK, !0 - error

Definition at line 1854 of file libavcodec/aacdec.c.

Referenced by aac_decode_frame_int().

static void decode_channel_map ( uint8_t  layout_map[][3], enum ChannelPosition  type, GetBitContext *  gb, int  n  )

static

Decode an array of 4 bit element IDs, optionally interleaved with a stereo/mono switching bit.

Parameters

type	speaker type/position for these channels

Definition at line 601 of file libavcodec/aacdec.c.

Referenced by decode_pce().

static int decode_cpe ( AACContext *  ac, GetBitContext *  gb, ChannelElement *  cpe  )

static

Decode a channel_pair_element; reference: table 4.4.

Returns

Returns error status. 0 - OK, !0 - error

Definition at line 1803 of file libavcodec/aacdec.c.

Referenced by aac_decode_frame_int().

static int decode_drc_channel_exclusions ( DynamicRangeControl *  che_drc, GetBitContext *  gb  )

static

Parse whether channels are to be excluded from Dynamic Range Compression; reference: table 4.53.

Returns

Returns number of bytes consumed.

Definition at line 1926 of file libavcodec/aacdec.c.

Referenced by decode_dynamic_range().

static int decode_dynamic_range ( DynamicRangeControl *  che_drc, GetBitContext *  gb  )

static

Decode dynamic range information; reference: table 4.52.

Returns

Returns number of bytes consumed.

Definition at line 1945 of file libavcodec/aacdec.c.

Referenced by decode_extension_payload().

static int decode_extension_payload ( AACContext *  ac, GetBitContext *  gb, int  cnt, ChannelElement *  che, enum RawDataBlockType  elem_type  )

static

Decode extension data (incomplete); reference: table 4.51.

Parameters

cnt	length of TYPE_FIL syntactic element in bytes

Returns

Returns number of bytes consumed

Definition at line 2025 of file libavcodec/aacdec.c.

Referenced by aac_decode_frame_int().

static int decode_fill ( AACContext *  ac, GetBitContext *  gb, int  len  )

static

Definition at line 1992 of file libavcodec/aacdec.c.

Referenced by decode_extension_payload().

static int decode_ga_specific_config ( AACContext *  ac, AVCodecContext *  avctx, GetBitContext *  gb, MPEG4AudioConfig *  m4ac, int  channel_config  )

static

Decode GA "General Audio" specific configuration; reference: table 4.1.

Parameters

ac	pointer to AACContext, may be null
avctx	pointer to AVCCodecContext, used for logging

Returns

Returns error status. 0 - OK, !0 - error

Definition at line 702 of file libavcodec/aacdec.c.

Referenced by decode_audio_specific_config().

static int decode_ics ( AACContext *  ac, SingleChannelElement *  sce, GetBitContext *  gb, int  common_window, int  scale_flag  )

static

Decode an individual_channel_stream payload; reference: table 4.44.

Parameters

common_window	Channels have independent [0], or shared [1], Individual Channel Stream information.
scale_flag	scalable [1] or non-scalable [0] AAC (Unused until scalable AAC is implemented.)

Returns

Returns error status. 0 - OK, !0 - error

Definition at line 1675 of file libavcodec/aacdec.c.

Referenced by aac_decode_frame_int(), decode_cce(), and decode_cpe().

static int decode_ics_info ( AACContext *  ac, IndividualChannelStream *  ics, GetBitContext *  gb  )

static

Decode Individual Channel Stream info; reference: table 4.6.

Definition at line 1028 of file libavcodec/aacdec.c.

Referenced by decode_cpe(), and decode_ics().

static void decode_ltp ( LongTermPrediction *  ltp, GetBitContext *  gb, uint8_t  max_sfb  )

static

Decode Long Term Prediction data; reference: table 4.xx.

Definition at line 1014 of file libavcodec/aacdec.c.

Referenced by decode_cpe(), and decode_ics_info().

static void decode_mid_side_stereo ( ChannelElement *  cpe, GetBitContext *  gb, int  ms_present  )

static

Decode Mid/Side data; reference: table 4.54.

Parameters

ms_present

Indicates mid/side stereo presence. [0] mask is all 0s; [1] mask is decoded from bitstream; [2] mask is all 1s; [3] reserved for scalable AAC

Definition at line 1281 of file libavcodec/aacdec.c.

Referenced by decode_cpe().

static int decode_pce ( AVCodecContext *  avctx, MPEG4AudioConfig *  m4ac, uint8_t(*)  layout_map[3], GetBitContext *  gb  )

static

Decode program configuration element; reference: table 4.2.

Returns

Returns error status. 0 - OK, !0 - error

Definition at line 635 of file libavcodec/aacdec.c.

Referenced by aac_decode_frame_int(), and decode_ga_specific_config().

static int decode_prediction ( AACContext *  ac, IndividualChannelStream *  ics, GetBitContext *  gb  )

static

Definition at line 994 of file libavcodec/aacdec.c.

Referenced by decode_ics_info().

static int decode_pulses ( Pulse *  pulse, GetBitContext *  gb, const uint16_t *  swb_offset, int  num_swb  )

static

Decode pulse data; reference: table 4.7.

Definition at line 1212 of file libavcodec/aacdec.c.

Referenced by decode_ics().

static int decode_scalefactors ( AACContext *  ac, float  sf[120], GetBitContext *  gb, unsigned int  global_gain, IndividualChannelStream *  ics, enum BandType  band_type[120], int  band_type_run_end[120]  )

static

Decode scalefactors; reference: table 4.47.

Parameters

global_gain	first scalefactor value as scalefactors are differentially coded
band_type	array of the used band type
band_type_run_end	array of the last scalefactor band of a band type run
sf	array of scalefactors or intensity stereo positions

Returns

Returns error status. 0 - OK, !0 - error

Definition at line 1150 of file libavcodec/aacdec.c.

Referenced by decode_ics().

static int decode_spectrum_and_dequant ( AACContext *  ac, float  coef[1024], GetBitContext *  gb, const float  sf[120], int  pulse_present, const Pulse *  pulse, const IndividualChannelStream *  ics, enum BandType  band_type[120]  )

static

Decode spectral data; reference: table 4.50.

Dequantize and scale spectral data; reference: 4.6.3.3.

Parameters

coef	array of dequantized, scaled spectral data
sf	array of scalefactors or intensity stereo positions
pulse_present	set if pulses are present
pulse	pointer to pulse data struct
band_type	array of the used band type

Returns

Returns error status. 0 - OK, !0 - error

Definition at line 1373 of file libavcodec/aacdec.c.

Referenced by decode_ics().

static int decode_tns ( AACContext *  ac, TemporalNoiseShaping *  tns, GetBitContext *  gb, const IndividualChannelStream *  ics  )

static

Decode Temporal Noise Shaping data; reference: table 4.48.

Returns

Returns error status. 0 - OK, !0 - error

Definition at line 1239 of file libavcodec/aacdec.c.

Referenced by decode_ics().

static av_always_inline float flt16_even ( float  pf )

static

Definition at line 1595 of file libavcodec/aacdec.c.

Referenced by predict().

static av_always_inline float flt16_round ( float  pf )

static

Definition at line 1587 of file libavcodec/aacdec.c.

Referenced by predict().

static av_always_inline float flt16_trunc ( float  pf )

static

Definition at line 1603 of file libavcodec/aacdec.c.

Referenced by predict().

static void flush ( AVCodecContext *  avctx )

static

Definition at line 472 of file libavcodec/aacdec.c.

Referenced by av_interleaved_write_frame(), bmp_parse(), decode_flush(), g726_reset(), gsm_flush(), libgsm_flush(), ogg_buffer_data(), png_parse(), and vp3_init_thread_copy().

static int frame_configure_elements ( AVCodecContext *  avctx )

static

Definition at line 176 of file libavcodec/aacdec.c.

Referenced by aac_decode_frame_int(), and output_configure().

static ChannelElement* get_che ( AACContext *  ac, int  type, int  elem_id  )

static

Definition at line 510 of file libavcodec/aacdec.c.

Referenced by aac_decode_frame_int().

static void imdct_and_windowing ( AACContext *  ac, SingleChannelElement *  sce  )

static

Conduct IMDCT and windowing.

Definition at line 2225 of file libavcodec/aacdec.c.

Referenced by aacdec_init().

static int latm_decode_audio_specific_config ( struct LATMContext *  latmctx, GetBitContext *  gb, int  asclen  )

static

Definition at line 2736 of file libavcodec/aacdec.c.

Referenced by read_stream_mux_config().

static int latm_decode_frame ( AVCodecContext *  avctx, void *  out, int *  got_frame_ptr, AVPacket *  avpkt  )

static

Definition at line 2925 of file libavcodec/aacdec.c.

static av_cold int latm_decode_init ( AVCodecContext *  avctx )

static

Definition at line 2976 of file libavcodec/aacdec.c.

static uint32_t latm_get_value ( GetBitContext *  b )

inlinestatic

Definition at line 2729 of file libavcodec/aacdec.c.

Referenced by read_stream_mux_config().

static av_always_inline int lcg_random ( unsigned  previous_val )

static

linear congruential pseudorandom number generator

Parameters

previous_val

pointer to the current state of the generator

Returns

Returns a 32-bit pseudorandom integer

Definition at line 829 of file libavcodec/aacdec.c.

Referenced by decode_spectrum_and_dequant().

static int output_configure ( AACContext *  ac, uint8_t  layout_map[MAX_ELEM_ID *4][3], int  tags, enum OCStatus  oc_type, int  get_new_frame  )

static

Configure output channel order based on the current program configuration element.

Returns

Returns error status. 0 - OK, !0 - error

Definition at line 423 of file libavcodec/aacdec.c.

Referenced by aac_decode_frame_int(), aac_decode_init(), decode_extension_payload(), decode_ga_specific_config(), get_che(), parse_adts_frame_header(), and pop_output_configuration().

static int parse_adts_frame_header ( AACContext *  ac, GetBitContext *  gb  )

static

dual mono frames in Japanese DTV can have chan_config 0 WITHOUT specifying PCE. thus, set dual mono as default.

Definition at line 2421 of file libavcodec/aacdec.c.

Referenced by aac_decode_frame_int().

static void pop_output_configuration ( AACContext *  ac )

static

Restore the previous output configuration if and only if the current configuration is unlocked.

Definition at line 408 of file libavcodec/aacdec.c.

Referenced by aac_decode_frame(), aac_decode_frame_int(), and latm_decode_frame().

static av_always_inline void predict ( PredictorState *  ps, float *  coef, int  output_enable  )

static

Definition at line 1611 of file libavcodec/aacdec.c.

Referenced by apply_prediction(), decode_line(), and encode_line().

static void push_output_configuration ( AACContext *  ac )

static

Save current output configuration if and only if it has been locked.

Definition at line 397 of file libavcodec/aacdec.c.

Referenced by aac_decode_frame(), aac_decode_frame_int(), get_che(), latm_decode_frame(), and parse_adts_frame_header().

static int read_audio_mux_element ( struct LATMContext *  latmctx, GetBitContext *  gb  )

static

Definition at line 2896 of file libavcodec/aacdec.c.

Referenced by latm_decode_frame().

static int read_payload_length_info ( struct LATMContext *  ctx, GetBitContext *  gb  )

static

Definition at line 2875 of file libavcodec/aacdec.c.

Referenced by read_audio_mux_element().

static int read_stream_mux_config ( struct LATMContext *  latmctx, GetBitContext *  gb  )

static

Definition at line 2795 of file libavcodec/aacdec.c.

Referenced by read_audio_mux_element().

static void reset_all_predictors ( PredictorState *  ps )

static

Definition at line 845 of file libavcodec/aacdec.c.

Referenced by apply_prediction().

static av_always_inline void reset_predict_state ( PredictorState *  ps )

static

Definition at line 835 of file libavcodec/aacdec.c.

Referenced by reset_all_predictors(), and reset_predictor_group().

static void reset_predictor_group ( PredictorState *  ps, int  group_num  )

static

Definition at line 868 of file libavcodec/aacdec.c.

Referenced by apply_prediction().

static int sample_rate_idx ( int  rate )

static

Definition at line 852 of file libavcodec/aacdec.c.

Referenced by aac_decode_init().

static int set_default_channel_config ( AVCodecContext *  avctx, uint8_t(*)  layout_map[3], int *  tags, int  channel_config  )

static

Set up channel positions based on a default channel configuration as specified in table 1.17.

Returns

Returns error status. 0 - OK, !0 - error

Definition at line 495 of file libavcodec/aacdec.c.

Referenced by aac_decode_init(), decode_ga_specific_config(), get_che(), and parse_adts_frame_header().

static int skip_data_stream_element ( AACContext *  ac, GetBitContext *  gb  )

static

Skip data_stream_element; reference: table 4.10.

Definition at line 977 of file libavcodec/aacdec.c.

Referenced by aac_decode_frame_int().

static uint64_t sniff_channel_order ( uint8_t(*)  layout_map[3], int  tags  )

static

Definition at line 264 of file libavcodec/aacdec.c.

Referenced by output_configure().

static void spectral_to_sample ( AACContext *  ac )

static

Convert spectral data to float samples, applying all supported tools as appropriate.

Definition at line 2378 of file libavcodec/aacdec.c.

Referenced by aac_decode_frame_int().

static void update_ltp ( AACContext *  ac, SingleChannelElement *  sce  )

static

Update the LTP buffer for next frame.

Definition at line 2190 of file libavcodec/aacdec.c.

Referenced by aacdec_init().

static float* VMUL2 ( float *  dst, const float *  v, unsigned  idx, const float *  scale  )

inlinestatic

Definition at line 1294 of file libavcodec/aacdec.c.

Referenced by decode_spectrum_and_dequant().

static float* VMUL2S ( float *  dst, const float *  v, unsigned  idx, unsigned  sign, const float *  scale  )

inlinestatic

Definition at line 1318 of file libavcodec/aacdec.c.

Referenced by decode_spectrum_and_dequant().

static float* VMUL4 ( float *  dst, const float *  v, unsigned  idx, const float *  scale  )

inlinestatic

Definition at line 1305 of file libavcodec/aacdec.c.

Referenced by decode_spectrum_and_dequant().

static float* VMUL4S ( float *  dst, const float *  v, unsigned  idx, unsigned  sign, const float *  scale  )

inlinestatic

Definition at line 1335 of file libavcodec/aacdec.c.

Referenced by decode_spectrum_and_dequant().

static void windowing_and_mdct_ltp ( AACContext *  ac, float *  out, float *  in, IndividualChannelStream *  ics  )

static

Apply windowing and MDCT to obtain the spectral coefficient from the predicted sample by LTP.

Definition at line 2132 of file libavcodec/aacdec.c.

Referenced by aacdec_init().

Variable Documentation

const AVClass aac_decoder_class

static

Initial value:

= {
    .class_name = "AAC decoder",
    .item_name  = av_default_item_name,
    .option     = options,
    .version    = LIBAVUTIL_VERSION_INT,
}

Definition at line 3015 of file libavcodec/aacdec.c.

const float cce_scale[]

static

Initial value:

= {
    1.09050773266525765921, 
    1.18920711500272106672, 
    M_SQRT2,
    2,
}

Definition at line 1842 of file libavcodec/aacdec.c.

AVCodec ff_aac_decoder

Initial value:

= {
    .name            = "aac",
    .type            = AVMEDIA_TYPE_AUDIO,
    .id              = AV_CODEC_ID_AAC,
    .priv_data_size  = sizeof(AACContext),
    .init            = aac_decode_init,
    .close           = aac_decode_close,
    .decode          = aac_decode_frame,
    .long_name       = NULL_IF_CONFIG_SMALL("AAC (Advanced Audio Coding)"),
    .sample_fmts     = (const enum AVSampleFormat[]) {
        AV_SAMPLE_FMT_FLTP, AV_SAMPLE_FMT_NONE
    },
    .capabilities    = CODEC_CAP_CHANNEL_CONF | CODEC_CAP_DR1,
    .channel_layouts = aac_channel_layout,
    .flush = flush,
    .priv_class      = &aac_decoder_class,
}

Definition at line 3022 of file libavcodec/aacdec.c.

AVCodec ff_aac_latm_decoder

Initial value:

= {
    .name            = "aac_latm",
    .type            = AVMEDIA_TYPE_AUDIO,
    .id              = AV_CODEC_ID_AAC_LATM,
    .priv_data_size  = sizeof(struct LATMContext),
    .init            = latm_decode_init,
    .close           = aac_decode_close,
    .decode          = latm_decode_frame,
    .long_name       = NULL_IF_CONFIG_SMALL("AAC LATM (Advanced Audio Coding LATM syntax)"),
    .sample_fmts     = (const enum AVSampleFormat[]) {
        AV_SAMPLE_FMT_FLTP, AV_SAMPLE_FMT_NONE
    },
    .capabilities    = CODEC_CAP_CHANNEL_CONF | CODEC_CAP_DR1,
    .channel_layouts = aac_channel_layout,
    .flush = flush,
}

Definition at line 3045 of file libavcodec/aacdec.c.

const AVOption options[]

static

Initial value:

= {
    {"dual_mono_mode", "Select the channel to decode for dual mono",
     offsetof(AACContext, force_dmono_mode), AV_OPT_TYPE_INT, {.i64=-1}, -1, 2,
     AACDEC_FLAGS, "dual_mono_mode"},

    {"auto", "autoselection",            0, AV_OPT_TYPE_CONST, {.i64=-1}, INT_MIN, INT_MAX, AACDEC_FLAGS, "dual_mono_mode"},
    {"main", "Select Main/Left channel", 0, AV_OPT_TYPE_CONST, {.i64= 1}, INT_MIN, INT_MAX, AACDEC_FLAGS, "dual_mono_mode"},
    {"sub" , "Select Sub/Right channel", 0, AV_OPT_TYPE_CONST, {.i64= 2}, INT_MIN, INT_MAX, AACDEC_FLAGS, "dual_mono_mode"},
    {"both", "Select both channels",     0, AV_OPT_TYPE_CONST, {.i64= 0}, INT_MIN, INT_MAX, AACDEC_FLAGS, "dual_mono_mode"},

    {NULL},
}

Definition at line 3002 of file libavcodec/aacdec.c.

VLC vlc_scalefactors

static

Definition at line 114 of file libavcodec/aacdec.c.

VLC vlc_spectral[11]

static

Definition at line 115 of file libavcodec/aacdec.c.