FFmpeg: libavcodec/psymodel.h File Reference

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libavcodec

Data Structures | Macros | Functions

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

#define PSY_MAX_CHANS 20

maximum number of channels

#define AAC_CUTOFF(s) (s->bit_rate ? FFMIN3(4000 + s->bit_rate/8, 12000 + s->bit_rate/32, s->sample_rate / 2) : (s->sample_rate / 2))

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.

FFPsyChannelGroup * ff_psy_find_group (FFPsyContext *ctx, int channel)

Determine what group a channel belongs to.

void ff_psy_end (FFPsyContext *ctx)

Cleanup model context at the end.

struct FFPsyPreprocessContext * ff_psy_preprocess_init (AVCodecContext *avctx)

psychoacoustic model audio preprocessing initialization

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

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

void ff_psy_preprocess_end (struct FFPsyPreprocessContext *ctx)

Cleanup audio preprocessing module.

Macro Definition Documentation

#define PSY_MAX_BANDS 128

maximum possible number of bands

Definition at line 28 of file psymodel.h.

#define PSY_MAX_CHANS 20

maximum number of channels

Definition at line 30 of file psymodel.h.

#define AAC_CUTOFF ( s ) (s->bit_rate ? FFMIN3(4000 + s->bit_rate/8, 12000 + s->bit_rate/32, s->sample_rate / 2) : (s->sample_rate / 2))

Definition at line 32 of file psymodel.h.

Referenced by ff_psy_preprocess_init(), and psy_3gpp_init().

Function Documentation

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().

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 66 of file psymodel.c.

Referenced by psy_3gpp_analyze().

void ff_psy_end ( FFPsyContext * ctx )

Cleanup model context at the end.

Parameters: ctx model context

Definition at line 76 of file psymodel.c.

Referenced by aac_encode_end().

struct FFPsyPreprocessContext* ff_psy_preprocess_init ( AVCodecContext * avctx )

read

psychoacoustic model audio preprocessing initialization

Definition at line 96 of file psymodel.c.

Referenced by aac_encode_init().

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 125 of file psymodel.c.

Referenced by aac_encode_frame().

void ff_psy_preprocess_end ( struct FFPsyPreprocessContext * ctx )

Cleanup audio preprocessing module.

Definition at line 138 of file psymodel.c.

Referenced by aac_encode_end().

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