psymodel.h File Reference

#include "avcodec.h"

Go to the source code of this file.

Data Structures
struct	FFPsyBand
	single band psychoacoustic information More...
struct	FFPsyChannel
	single channel psychoacoustic information More...
struct	FFPsyChannelGroup
	psychoacoustic information for an arbitrary group of channels More...
struct	FFPsyWindowInfo
	windowing related information More...
struct	FFPsyContext
	context used by psychoacoustic model More...
struct	FFPsyModel
	codec-specific psychoacoustic model implementation More...

Macros
#define	PSY_MAX_BANDS   128
	maximum possible number of bands More...
#define	PSY_MAX_CHANS   20
	maximum number of channels More...
#define	AAC_CUTOFF_FROM_BITRATE(bit_rate, channels, sample_rate)
#define	AAC_CUTOFF(s)

Functions
int	ff_psy_init (FFPsyContext *ctx, AVCodecContext *avctx, int num_lens, const uint8_t **bands, const int *num_bands, int num_groups, const uint8_t *group_map)
	Initialize psychoacoustic model. More...
FFPsyChannelGroup *	ff_psy_find_group (FFPsyContext *ctx, int channel)
	Determine what group a channel belongs to. More...
void	ff_psy_end (FFPsyContext *ctx)
	Cleanup model context at the end. More...
struct FFPsyPreprocessContext *	ff_psy_preprocess_init (AVCodecContext *avctx)
	psychoacoustic model audio preprocessing initialization More...
void	ff_psy_preprocess (struct FFPsyPreprocessContext *ctx, float **audio, int channels)
	Preprocess several channel in audio frame in order to compress it better. More...
void	ff_psy_preprocess_end (struct FFPsyPreprocessContext *ctx)
	Cleanup audio preprocessing module. More...

Macro Definition Documentation

PSY_MAX_BANDS

#define PSY_MAX_BANDS   128

maximum possible number of bands

Definition at line 28 of file psymodel.h.

PSY_MAX_CHANS

#define PSY_MAX_CHANS   20

maximum number of channels

Definition at line 30 of file psymodel.h.

AAC_CUTOFF_FROM_BITRATE

#define AAC_CUTOFF_FROM_BITRATE	(		bit_rate,
			channels,
			sample_rate
	)

Value:

    (bit_rate ? FFMIN3(FFMIN3( \
    FFMAX(bit_rate/channels/5, bit_rate/channels*15/32 - 5500), \
    3000 + bit_rate/channels/4, \
    12000 + bit_rate/channels/16), \
    22000, \
    sample_rate / 2): (sample_rate / 2))

Definition at line 35 of file psymodel.h.

AAC_CUTOFF

#define AAC_CUTOFF

(

s

)

Value:

    ( \
    (s->flags & AV_CODEC_FLAG_QSCALE) \
    ? s->sample_rate / 2 \
    : AAC_CUTOFF_FROM_BITRATE(s->bit_rate, s->channels, s->sample_rate) \
)

Definition at line 41 of file psymodel.h.

Function Documentation

ff_psy_init()

int ff_psy_init	(	FFPsyContext *	ctx,
		AVCodecContext *	avctx,
		int	num_lens,
		const uint8_t **	bands,
		const int *	num_bands,
		int	num_groups,
		const uint8_t *	group_map
	)

Initialize psychoacoustic model.

Parameters

ctx	model context
avctx	codec context
num_lens	number of possible frame lengths
bands	scalefactor band lengths for all frame lengths
num_bands	number of scalefactor bands for all frame lengths
num_groups	number of channel groups
group_map	array with # of channels in group - 1, for each group

Returns

zero if successful, a negative value if not

Definition at line 31 of file psymodel.c.

Referenced by aac_encode_init().

ff_psy_find_group()

FFPsyChannelGroup* ff_psy_find_group	(	FFPsyContext *	ctx,
		int	channel
	)

Determine what group a channel belongs to.

Parameters

ctx	psymodel context
channel	channel to locate the group for

Returns

pointer to the FFPsyChannelGroup this channel belongs to

Definition at line 73 of file psymodel.c.

Referenced by psy_3gpp_analyze().

ff_psy_end()

void ff_psy_end

(

FFPsyContext *

ctx

)

Cleanup model context at the end.

Parameters

ctx	model context

Definition at line 83 of file psymodel.c.

Referenced by aac_encode_end(), and ff_psy_init().

ff_psy_preprocess_init()

struct FFPsyPreprocessContext* ff_psy_preprocess_init

(

AVCodecContext *

avctx

)

psychoacoustic model audio preprocessing initialization

Definition at line 103 of file psymodel.c.

Referenced by aac_encode_init().

ff_psy_preprocess()

void ff_psy_preprocess	(	struct FFPsyPreprocessContext *	ctx,
		float **	audio,
		int	channels
	)

Preprocess several channel in audio frame in order to compress it better.

Parameters

ctx	preprocessing context
audio	samples to be filtered (in place)
channels	number of channel to preprocess

Definition at line 139 of file psymodel.c.

Referenced by aac_encode_frame().

ff_psy_preprocess_end()

void ff_psy_preprocess_end

(

struct FFPsyPreprocessContext *

ctx

)

Cleanup audio preprocessing module.

Definition at line 152 of file psymodel.c.

Referenced by aac_encode_end().