AAC encoder psychoacoustic model. More...

#include "libavutil/libm.h"
#include "avcodec.h"
#include "aactab.h"
#include "psymodel.h"

Include dependency graph for aacpsy.c:

Data Structures
struct	AacPsyBand
	information for single band used by 3GPP TS26.403-inspired psychoacoustic model More...

struct	AacPsyChannel
	single/pair channel context for psychoacoustic model More...

struct	AacPsyCoeffs
	psychoacoustic model frame type-dependent coefficients More...

struct	AacPsyContext
	3GPP TS26.403-inspired psychoacoustic model specific data More...

struct	PsyLamePreset
	LAME psy model preset struct. More...

Macros
#define	ATH_ADD 4

Typedefs
typedef struct AacPsyBand	AacPsyBand
	information for single band used by 3GPP TS26.403-inspired psychoacoustic model More...

typedef struct AacPsyChannel	AacPsyChannel
	single/pair channel context for psychoacoustic model More...

typedef struct AacPsyCoeffs	AacPsyCoeffs
	psychoacoustic model frame type-dependent coefficients More...

typedef struct AacPsyContext	AacPsyContext
	3GPP TS26.403-inspired psychoacoustic model specific data More...

Functions
static float	lame_calc_attack_threshold (int bitrate)
	Calculate the ABR attack threshold from the above LAME psymodel table. More...

static void	lame_window_init (AacPsyContext ctx, AVCodecContext avctx)
	LAME psy model specific initialization. More...

static av_cold float	calc_bark (float f)
	Calculate Bark value for given line. More...

static av_cold float	ath (float f, float add)
	Calculate ATH value for given frequency. More...

static av_cold int	psy_3gpp_init (FFPsyContext *ctx)

static float	iir_filter (int in, float state[2])
	IIR filter used in block switching decision. More...

static av_unused FFPsyWindowInfo	psy_3gpp_window (FFPsyContext ctx, const int16_t audio, const int16_t *la, int channel, int prev_type)
	Tell encoder which window types to use. More...

static int	calc_bit_demand (AacPsyContext *ctx, float pe, int bits, int size, int short_window)

static float	calc_pe_3gpp (AacPsyBand *band)

static float	calc_reduction_3gpp (float a, float desired_pe, float pe, float active_lines)

static float	calc_reduced_thr_3gpp (AacPsyBand *band, float min_snr, float reduction)

static void	calc_thr_3gpp (const FFPsyWindowInfo wi, const int num_bands, AacPsyChannel pch, const uint8_t band_sizes, const float coefs)

static void	psy_hp_filter (const float firbuf, float hpfsmpl, const float *psy_fir_coeffs)

static void	psy_3gpp_analyze_channel (FFPsyContext ctx, int channel, const float coefs, const FFPsyWindowInfo *wi)
	Calculate band thresholds as suggested in 3GPP TS26.403. More...

static void	psy_3gpp_analyze (FFPsyContext ctx, int channel, const float coeffs, const FFPsyWindowInfo wi)

static av_cold void	psy_3gpp_end (FFPsyContext *apc)

static void	lame_apply_block_type (AacPsyChannel ctx, FFPsyWindowInfo wi, int uselongblock)

static FFPsyWindowInfo	psy_lame_window (FFPsyContext ctx, const float audio, const float *la, int channel, int prev_type)

Variables
static const PsyLamePreset	psy_abr_map []
	LAME psy model preset table for ABR. More...

static const PsyLamePreset	psy_vbr_map []
	LAME psy model preset table for constant quality. More...

static const float	psy_fir_coeffs []
	LAME psy model FIR coefficient table. More...

static const uint8_t	window_grouping [9]
	window grouping information stored as bits (0 - new group, 1 - group continues) More...

const FFPsyModel	ff_aac_psy_model

#define	PSY_3GPP_THR_SPREAD_HI 1.5f
	constants for 3GPP AAC psychoacoustic model More...

#define	PSY_3GPP_THR_SPREAD_LOW 3.0f

#define	PSY_3GPP_EN_SPREAD_HI_L1 2.0f

#define	PSY_3GPP_EN_SPREAD_HI_L2 1.5f

#define	PSY_3GPP_EN_SPREAD_HI_S 1.5f

#define	PSY_3GPP_EN_SPREAD_LOW_L 3.0f

#define	PSY_3GPP_EN_SPREAD_LOW_S 2.0f

#define	PSY_3GPP_RPEMIN 0.01f

#define	PSY_3GPP_RPELEV 2.0f

#define	PSY_3GPP_C1 3.0f /* log2(8) */

#define	PSY_3GPP_C2 1.3219281f /* log2(2.5) */

#define	PSY_3GPP_C3 0.55935729f /* 1 - C2 / C1 */

#define	PSY_SNR_1DB 7.9432821e-1f /* -1dB */

#define	PSY_SNR_25DB 3.1622776e-3f /* -25dB */

#define	PSY_3GPP_SAVE_SLOPE_L -0.46666667f

#define	PSY_3GPP_SAVE_SLOPE_S -0.36363637f

#define	PSY_3GPP_SAVE_ADD_L -0.84285712f

#define	PSY_3GPP_SAVE_ADD_S -0.75f

#define	PSY_3GPP_SPEND_SLOPE_L 0.66666669f

#define	PSY_3GPP_SPEND_SLOPE_S 0.81818181f

#define	PSY_3GPP_SPEND_ADD_L -0.35f

#define	PSY_3GPP_SPEND_ADD_S -0.26111111f

#define	PSY_3GPP_CLIP_LO_L 0.2f

#define	PSY_3GPP_CLIP_LO_S 0.2f

#define	PSY_3GPP_CLIP_HI_L 0.95f

#define	PSY_3GPP_CLIP_HI_S 0.75f

#define	PSY_3GPP_AH_THR_LONG 0.5f

#define	PSY_3GPP_AH_THR_SHORT 0.63f

#define	PSY_3GPP_BITS_TO_PE(bits) ((bits) * 1.18f)

#define	PSY_LAME_FIR_LEN 21
	LAME psy model FIR order. More...

#define	AAC_BLOCK_SIZE_LONG 1024
	long block size More...

#define	AAC_BLOCK_SIZE_SHORT 128
	short block size More...

#define	AAC_NUM_BLOCKS_SHORT 8
	number of blocks in a short sequence More...

#define	PSY_LAME_NUM_SUBBLOCKS 3
	Number of sub-blocks in each short block. More...

enum	{ PSY_3GPP_AH_NONE, PSY_3GPP_AH_INACTIVE, PSY_3GPP_AH_ACTIVE }

Detailed Description

AAC encoder psychoacoustic model.

Definition in file aacpsy.c.

Macro Definition Documentation

#define AAC_BLOCK_SIZE_LONG 1024

long block size

Definition at line 92 of file aacpsy.c.

Referenced by psy_3gpp_init(), and psy_hp_filter().

#define AAC_BLOCK_SIZE_SHORT 128

short block size

Definition at line 93 of file aacpsy.c.

#define AAC_NUM_BLOCKS_SHORT 8

number of blocks in a short sequence

Definition at line 94 of file aacpsy.c.

Referenced by lame_window_init(), and psy_lame_window().

#define ATH_ADD 4

Definition at line 281 of file aacpsy.c.

Referenced by psy_3gpp_init().

#define PSY_3GPP_AH_THR_LONG 0.5f

Definition at line 79 of file aacpsy.c.

#define PSY_3GPP_AH_THR_SHORT 0.63f

Definition at line 80 of file aacpsy.c.

#define PSY_3GPP_BITS_TO_PE ( bits ) ((bits) * 1.18f)

Definition at line 88 of file aacpsy.c.

Referenced by psy_3gpp_init().

#define PSY_3GPP_C1 3.0f /* log2(8) */

Definition at line 59 of file aacpsy.c.

Referenced by calc_pe_3gpp().

#define PSY_3GPP_C2 1.3219281f /* log2(2.5) */

Definition at line 60 of file aacpsy.c.

Referenced by calc_pe_3gpp().

#define PSY_3GPP_C3 0.55935729f /* 1 - C2 / C1 */

Definition at line 61 of file aacpsy.c.

Referenced by calc_pe_3gpp().

#define PSY_3GPP_CLIP_HI_L 0.95f

Definition at line 76 of file aacpsy.c.

Referenced by calc_bit_demand().

#define PSY_3GPP_CLIP_HI_S 0.75f

Definition at line 77 of file aacpsy.c.

Referenced by calc_bit_demand().

#define PSY_3GPP_CLIP_LO_L 0.2f

Definition at line 74 of file aacpsy.c.

Referenced by calc_bit_demand().

#define PSY_3GPP_CLIP_LO_S 0.2f

Definition at line 75 of file aacpsy.c.

Referenced by calc_bit_demand().

#define PSY_3GPP_EN_SPREAD_HI_L1 2.0f

Definition at line 46 of file aacpsy.c.

Referenced by psy_3gpp_init().

#define PSY_3GPP_EN_SPREAD_HI_L2 1.5f

Definition at line 48 of file aacpsy.c.

#define PSY_3GPP_EN_SPREAD_HI_S 1.5f

Definition at line 50 of file aacpsy.c.

Referenced by psy_3gpp_init().

#define PSY_3GPP_EN_SPREAD_LOW_L 3.0f

Definition at line 52 of file aacpsy.c.

Referenced by psy_3gpp_init().

#define PSY_3GPP_EN_SPREAD_LOW_S 2.0f

Definition at line 54 of file aacpsy.c.

Referenced by psy_3gpp_init().

#define PSY_3GPP_RPELEV 2.0f

Definition at line 57 of file aacpsy.c.

#define PSY_3GPP_RPEMIN 0.01f

Definition at line 56 of file aacpsy.c.

#define PSY_3GPP_SAVE_ADD_L -0.84285712f

Definition at line 68 of file aacpsy.c.

Referenced by calc_bit_demand().

#define PSY_3GPP_SAVE_ADD_S -0.75f

Definition at line 69 of file aacpsy.c.

Referenced by calc_bit_demand().

#define PSY_3GPP_SAVE_SLOPE_L -0.46666667f

Definition at line 66 of file aacpsy.c.

Referenced by calc_bit_demand().

#define PSY_3GPP_SAVE_SLOPE_S -0.36363637f

Definition at line 67 of file aacpsy.c.

Referenced by calc_bit_demand().

#define PSY_3GPP_SPEND_ADD_L -0.35f

Definition at line 72 of file aacpsy.c.

Referenced by calc_bit_demand().

#define PSY_3GPP_SPEND_ADD_S -0.26111111f

Definition at line 73 of file aacpsy.c.

Referenced by calc_bit_demand().

#define PSY_3GPP_SPEND_SLOPE_L 0.66666669f

Definition at line 70 of file aacpsy.c.

Referenced by calc_bit_demand().

#define PSY_3GPP_SPEND_SLOPE_S 0.81818181f

Definition at line 71 of file aacpsy.c.

Referenced by calc_bit_demand().

#define PSY_3GPP_THR_SPREAD_HI 1.5f

constants for 3GPP AAC psychoacoustic model

Definition at line 43 of file aacpsy.c.

Referenced by psy_3gpp_init().

#define PSY_3GPP_THR_SPREAD_LOW 3.0f

Definition at line 44 of file aacpsy.c.

Referenced by psy_3gpp_init().

#define PSY_LAME_FIR_LEN 21

LAME psy model FIR order.

Definition at line 91 of file aacpsy.c.

Referenced by psy_hp_filter().

#define PSY_LAME_NUM_SUBBLOCKS 3

Number of sub-blocks in each short block.

Definition at line 95 of file aacpsy.c.

Referenced by lame_window_init().

#define PSY_SNR_1DB 7.9432821e-1f /* -1dB */

Definition at line 63 of file aacpsy.c.

Referenced by psy_3gpp_init().

#define PSY_SNR_25DB 3.1622776e-3f /* -25dB */

Definition at line 64 of file aacpsy.c.

Referenced by psy_3gpp_init().

Typedef Documentation

typedef struct AacPsyBand AacPsyBand

information for single band used by 3GPP TS26.403-inspired psychoacoustic model

typedef struct AacPsyChannel AacPsyChannel

single/pair channel context for psychoacoustic model

typedef struct AacPsyCoeffs AacPsyCoeffs

psychoacoustic model frame type-dependent coefficients

typedef struct AacPsyContext AacPsyContext

3GPP TS26.403-inspired psychoacoustic model specific data

Enumeration Type Documentation

anonymous enum

Enumerator
PSY_3GPP_AH_NONE
PSY_3GPP_AH_INACTIVE
PSY_3GPP_AH_ACTIVE

Definition at line 82 of file aacpsy.c.

Function Documentation

static av_cold float ath	(	float	f,
		float	add
	)

static

Calculate ATH value for given frequency.

Borrowed from Lame.

Definition at line 286 of file aacpsy.c.

Referenced by psy_3gpp_init().

static av_cold float calc_bark ( float f )

static

Calculate Bark value for given line.

Definition at line 276 of file aacpsy.c.

Referenced by psy_3gpp_init().

static int calc_bit_demand	(	AacPsyContext *	ctx,
		float	pe,
		int	bits,
		int	size,
		int	short_window
	)

static

Definition at line 472 of file aacpsy.c.

static float calc_pe_3gpp ( AacPsyBand * band )

static

Definition at line 505 of file aacpsy.c.

static float calc_reduced_thr_3gpp	(	AacPsyBand *	band,
		float	min_snr,
		float	reduction
	)

static

Definition at line 542 of file aacpsy.c.

static float calc_reduction_3gpp	(	float	a,
		float	desired_pe,
		float	pe,
		float	active_lines
	)

static

Definition at line 528 of file aacpsy.c.

static void calc_thr_3gpp	(	const FFPsyWindowInfo *	wi,
		const int	num_bands,
		AacPsyChannel *	pch,
		const uint8_t *	band_sizes,
		const float *	coefs
	)

static

Definition at line 568 of file aacpsy.c.

static float iir_filter	(	int	in,
		float	state[2]
	)

static

IIR filter used in block switching decision.

Definition at line 365 of file aacpsy.c.

static void lame_apply_block_type	(	AacPsyChannel *	ctx,
		FFPsyWindowInfo *	wi,
		int	uselongblock
	)

static

Definition at line 801 of file aacpsy.c.

static float lame_calc_attack_threshold ( int bitrate )

static

Calculate the ABR attack threshold from the above LAME psymodel table.

Definition at line 227 of file aacpsy.c.

Referenced by lame_window_init().

static void lame_window_init	(	AacPsyContext *	ctx,
		AVCodecContext *	avctx
	)

static

LAME psy model specific initialization.

Definition at line 257 of file aacpsy.c.

Referenced by psy_3gpp_init().

static void psy_3gpp_analyze	(	FFPsyContext *	ctx,
		int	channel,
		const float **	coeffs,
		const FFPsyWindowInfo *	wi
	)

static

Definition at line 784 of file aacpsy.c.

static void psy_3gpp_analyze_channel	(	FFPsyContext *	ctx,
		int	channel,
		const float *	coefs,
		const FFPsyWindowInfo *	wi
	)

static

Calculate band thresholds as suggested in 3GPP TS26.403.

Definition at line 615 of file aacpsy.c.

Referenced by psy_3gpp_analyze().

static av_cold void psy_3gpp_end ( FFPsyContext * apc )

static

Definition at line 794 of file aacpsy.c.

static av_cold int psy_3gpp_init ( FFPsyContext * ctx )

static

Definition at line 295 of file aacpsy.c.

static av_unused FFPsyWindowInfo psy_3gpp_window	(	FFPsyContext *	ctx,
		const int16_t *	audio,
		const int16_t *	la,
		int	channel,
		int	prev_type
	)

static

Tell encoder which window types to use.

See also: 3GPP TS26.403 5.4.1 "Blockswitching"

Definition at line 386 of file aacpsy.c.

static void psy_hp_filter	(	const float *	firbuf,
		float *	hpfsmpl,
		const float *	psy_fir_coeffs
	)

static

Definition at line 595 of file aacpsy.c.

static FFPsyWindowInfo psy_lame_window	(	FFPsyContext *	ctx,
		const float *	audio,
		const float *	la,
		int	channel,
		int	prev_type
	)

static

Definition at line 819 of file aacpsy.c.

Variable Documentation

const FFPsyModel ff_aac_psy_model

Initial value:

=
{
    .name    = "3GPP TS 26.403-inspired model",
    .init    = psy_3gpp_init,
    .window  = psy_lame_window,
    .analyze = psy_3gpp_analyze,
    .end     = psy_3gpp_end,
}

Definition at line 955 of file aacpsy.c.

Referenced by ff_psy_init().

const PsyLamePreset psy_abr_map[]

static

Initial value:

= {
    {  8,  6.60},
    { 16,  6.60},
    { 24,  6.60},
    { 32,  6.60},
    { 40,  6.60},
    { 48,  6.60},
    { 56,  6.60},
    { 64,  6.40},
    { 80,  6.00},
    { 96,  5.60},
    {112,  5.20},
    {128,  5.20},
    {160,  5.20}
}

LAME psy model preset table for ABR.

Definition at line 175 of file aacpsy.c.

const float psy_fir_coeffs[]

static

Initial value:

= {
    -8.65163e-18 * 2, -0.00851586 * 2, -6.74764e-18 * 2, 0.0209036 * 2,
    -3.36639e-17 * 2, -0.0438162 * 2,  -1.54175e-17 * 2, 0.0931738 * 2,
    -5.52212e-17 * 2, -0.313819 * 2
}

LAME psy model FIR coefficient table.

Definition at line 214 of file aacpsy.c.

const PsyLamePreset psy_vbr_map[]

static

Initial value:

= {
    { 0,  4.20},
    { 1,  4.20},
    { 2,  4.20},
    { 3,  4.20},
    { 4,  4.20},
    { 5,  4.20},
    { 6,  4.20},
    { 7,  4.20},
    { 8,  4.20},
    { 9,  4.20},
    {10,  4.20}
}

LAME psy model preset table for constant quality.

Definition at line 196 of file aacpsy.c.

const uint8_t window_grouping[9]

static

Initial value:

= {
    0xB6, 0x6C, 0xD8, 0xB2, 0x66, 0xC6, 0x96, 0x36, 0x36
}

window grouping information stored as bits (0 - new group, 1 - group continues)

Definition at line 378 of file aacpsy.c.

Paris Hackday Code

Data Structures

Macros

Typedefs

Functions

Variables

Detailed Description

Macro Definition Documentation

Typedef Documentation

Enumeration Type Documentation

Function Documentation

Variable Documentation