FFmpeg: libavcodec/aac.h File Reference

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Data Structures | Macros | Enumerations | Functions

aac.h File Reference

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Data Structures

struct Pulse

Macros

#define MAX_CHANNELS 64

#define MAX_ELEM_ID 64

#define TNS_MAX_ORDER 20

#define MAX_LTP_LONG_SFB 40

#define MAX_PREDICTORS 672

#define SCALE_DIV_512 36

scalefactor difference that corresponds to scale difference in 512 times More...

#define SCALE_ONE_POS 140

scalefactor index that corresponds to scale=1.0 More...

#define SCALE_MAX_POS 255

scalefactor index maximum value More...

#define SCALE_MAX_DIFF 60

maximum scalefactor difference allowed by standard More...

#define SCALE_DIFF_ZERO 60

codebook index corresponding to zero scalefactor indices difference More...

#define POW_SF2_ZERO 200

ff_aac_pow2sf_tab index corresponding to pow(2, 0); More...

#define NOISE_PRE 256

preamble for NOISE_BT, put in bitstream with the first noise band More...

#define NOISE_PRE_BITS 9

length of preamble More...

#define NOISE_OFFSET 90

subtracted from global gain, used as offset for the preamble More...

Enumerations

enum RawDataBlockType {
TYPE_SCE, TYPE_CPE, TYPE_CCE, TYPE_LFE,
TYPE_DSE, TYPE_PCE, TYPE_FIL, TYPE_END
}

enum ExtensionPayloadID {
EXT_FILL, EXT_FILL_DATA, EXT_DATA_ELEMENT, EXT_DYNAMIC_RANGE = 0xb,
EXT_SBR_DATA = 0xd, EXT_SBR_DATA_CRC = 0xe
}

enum WindowSequence { ONLY_LONG_SEQUENCE, LONG_START_SEQUENCE, EIGHT_SHORT_SEQUENCE, LONG_STOP_SEQUENCE }

enum BandType {
ZERO_BT = 0, FIRST_PAIR_BT = 5, ESC_BT = 11, RESERVED_BT = 12,
NOISE_BT = 13, INTENSITY_BT2 = 14, INTENSITY_BT = 15
}

enum ChannelPosition {
AAC_CHANNEL_OFF = 0, AAC_CHANNEL_FRONT = 1, AAC_CHANNEL_SIDE = 2, AAC_CHANNEL_BACK = 3,
AAC_CHANNEL_LFE = 4, AAC_CHANNEL_CC = 5
}

Functions

static int ff_aac_sample_rate_idx (int rate)

Detailed Description

AAC definitions and structures

Author: Oded Shimon ( ods15 ods15 dyndns org ); Maxim Gavrilov ( maxim.gavrilov gmail com )

Definition in file aac.h.

Macro Definition Documentation

◆ MAX_CHANNELS

#define MAX_CHANNELS 64

Definition at line 33 of file aac.h.

◆ MAX_ELEM_ID

#define MAX_ELEM_ID 64

Definition at line 34 of file aac.h.

◆ TNS_MAX_ORDER

#define TNS_MAX_ORDER 20

Definition at line 36 of file aac.h.

◆ MAX_LTP_LONG_SFB

#define MAX_LTP_LONG_SFB 40

Definition at line 37 of file aac.h.

◆ MAX_PREDICTORS

#define MAX_PREDICTORS 672

Definition at line 85 of file aac.h.

◆ SCALE_DIV_512

#define SCALE_DIV_512 36

scalefactor difference that corresponds to scale difference in 512 times

Definition at line 87 of file aac.h.

◆ SCALE_ONE_POS

#define SCALE_ONE_POS 140

scalefactor index that corresponds to scale=1.0

Definition at line 88 of file aac.h.

◆ SCALE_MAX_POS

#define SCALE_MAX_POS 255

scalefactor index maximum value

Definition at line 89 of file aac.h.

◆ SCALE_MAX_DIFF

#define SCALE_MAX_DIFF 60

maximum scalefactor difference allowed by standard

Definition at line 90 of file aac.h.

◆ SCALE_DIFF_ZERO

#define SCALE_DIFF_ZERO 60

codebook index corresponding to zero scalefactor indices difference

Definition at line 91 of file aac.h.

◆ POW_SF2_ZERO

#define POW_SF2_ZERO 200

ff_aac_pow2sf_tab index corresponding to pow(2, 0);

Definition at line 93 of file aac.h.

◆ NOISE_PRE

#define NOISE_PRE 256

preamble for NOISE_BT, put in bitstream with the first noise band

Definition at line 95 of file aac.h.

◆ NOISE_PRE_BITS

#define NOISE_PRE_BITS 9

length of preamble

Definition at line 96 of file aac.h.

◆ NOISE_OFFSET

#define NOISE_OFFSET 90

subtracted from global gain, used as offset for the preamble

Definition at line 97 of file aac.h.

Enumeration Type Documentation

◆ RawDataBlockType

enum RawDataBlockType

Enumerator
TYPE_SCE
TYPE_CPE
TYPE_CCE
TYPE_LFE
TYPE_DSE
TYPE_PCE
TYPE_FIL
TYPE_END

Definition at line 39 of file aac.h.

◆ ExtensionPayloadID

enum ExtensionPayloadID

Enumerator
EXT_FILL
EXT_FILL_DATA
EXT_DATA_ELEMENT
EXT_DYNAMIC_RANGE
EXT_SBR_DATA
EXT_SBR_DATA_CRC

Definition at line 50 of file aac.h.

◆ WindowSequence

enum WindowSequence

Enumerator
ONLY_LONG_SEQUENCE
LONG_START_SEQUENCE
EIGHT_SHORT_SEQUENCE
LONG_STOP_SEQUENCE

Definition at line 59 of file aac.h.

◆ BandType

enum BandType

Enumerator
ZERO_BT	Scalefactors and spectral data are all zero.
FIRST_PAIR_BT	This and later band types encode two values (rather than four) with one code word.
ESC_BT	Spectral data are coded with an escape sequence.
RESERVED_BT	Band types following are encoded differently from others.
NOISE_BT	Spectral data are scaled white noise not coded in the bitstream.
INTENSITY_BT2	Scalefactor data are intensity stereo positions (out of phase).
INTENSITY_BT	Scalefactor data are intensity stereo positions (in phase).

Definition at line 66 of file aac.h.

◆ ChannelPosition

enum ChannelPosition

Enumerator
AAC_CHANNEL_OFF
AAC_CHANNEL_FRONT
AAC_CHANNEL_SIDE
AAC_CHANNEL_BACK
AAC_CHANNEL_LFE
AAC_CHANNEL_CC

Definition at line 76 of file aac.h.

Function Documentation

◆ ff_aac_sample_rate_idx()

static int ff_aac_sample_rate_idx ( int rate )

inlinestatic

Definition at line 106 of file aac.h.

Referenced by ff_aac_decode_init(), and ff_aac_usac_config_decode().

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