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Rev	Author	Line No.	Line
6148	serge	1	/*
		2	* audio encoder psychoacoustic model
		3	* Copyright (C) 2008 Konstantin Shishkov
		4	*
		5	* This file is part of FFmpeg.
		6	*
		7	* FFmpeg is free software; you can redistribute it and/or
		8	* modify it under the terms of the GNU Lesser General Public
		9	* License as published by the Free Software Foundation; either
		10	* version 2.1 of the License, or (at your option) any later version.
		11	*
		12	* FFmpeg is distributed in the hope that it will be useful,
		13	* but WITHOUT ANY WARRANTY; without even the implied warranty of
		14	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
		15	* Lesser General Public License for more details.
		16	*
		17	* You should have received a copy of the GNU Lesser General Public
		18	* License along with FFmpeg; if not, write to the Free Software
		19	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
		20	*/
		21
		22	#ifndef AVCODEC_PSYMODEL_H
		23	#define AVCODEC_PSYMODEL_H
		24
		25	#include "avcodec.h"
		26
		27	/** maximum possible number of bands */
		28	#define PSY_MAX_BANDS 128
		29	/** maximum number of channels */
		30	#define PSY_MAX_CHANS 20
		31
		32	#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))
		33
		34	/**
		35	* single band psychoacoustic information
		36	*/
		37	typedef struct FFPsyBand {
		38	int bits;
		39	float energy;
		40	float threshold;
		41	float distortion;
		42	float perceptual_weight;
		43	} FFPsyBand;
		44
		45	/**
		46	* single channel psychoacoustic information
		47	*/
		48	typedef struct FFPsyChannel {
		49	FFPsyBand psy_bands[PSY_MAX_BANDS]; ///< channel bands information
		50	float entropy; ///< total PE for this channel
		51	} FFPsyChannel;
		52
		53	/**
		54	* psychoacoustic information for an arbitrary group of channels
		55	*/
		56	typedef struct FFPsyChannelGroup {
		57	FFPsyChannel *ch[PSY_MAX_CHANS]; ///< pointers to the individual channels in the group
		58	uint8_t num_ch; ///< number of channels in this group
		59	uint8_t coupling[PSY_MAX_BANDS]; ///< allow coupling for this band in the group
		60	} FFPsyChannelGroup;
		61
		62	/**
		63	* windowing related information
		64	*/
		65	typedef struct FFPsyWindowInfo {
		66	int window_type[3]; ///< window type (short/long/transitional, etc.) - current, previous and next
		67	int window_shape; ///< window shape (sine/KBD/whatever)
		68	int num_windows; ///< number of windows in a frame
		69	int grouping[8]; ///< window grouping (for e.g. AAC)
		70	int *window_sizes; ///< sequence of window sizes inside one frame (for eg. WMA)
		71	} FFPsyWindowInfo;
		72
		73	/**
		74	* context used by psychoacoustic model
		75	*/
		76	typedef struct FFPsyContext {
		77	AVCodecContext *avctx; ///< encoder context
		78	const struct FFPsyModel *model; ///< encoder-specific model functions
		79
		80	FFPsyChannel *ch; ///< single channel information
		81	FFPsyChannelGroup *group; ///< channel group information
		82	int num_groups; ///< number of channel groups
		83
		84	uint8_t **bands; ///< scalefactor band sizes for possible frame sizes
		85	int *num_bands; ///< number of scalefactor bands for possible frame sizes
		86	int num_lens; ///< number of scalefactor band sets
		87
		88	struct {
		89	int size; ///< size of the bitresevoir in bits
		90	int bits; ///< number of bits used in the bitresevoir
		91	} bitres;
		92
		93	void* model_priv_data; ///< psychoacoustic model implementation private data
		94	} FFPsyContext;
		95
		96	/**
		97	* codec-specific psychoacoustic model implementation
		98	*/
		99	typedef struct FFPsyModel {
		100	const char *name;
		101	int (init) (FFPsyContext apc);
		102
		103	/**
		104	* Suggest window sequence for channel.
		105	*
		106	* @param ctx model context
		107	* @param audio samples for the current frame
		108	* @param la lookahead samples (NULL when unavailable)
		109	* @param channel number of channel element to analyze
		110	* @param prev_type previous window type
		111	*
		112	* @return suggested window information in a structure
		113	*/
		114	FFPsyWindowInfo (window)(FFPsyContext ctx, const float audio, const float la, int channel, int prev_type);
		115
		116	/**
		117	* Perform psychoacoustic analysis and set band info (threshold, energy) for a group of channels.
		118	*
		119	* @param ctx model context
		120	* @param channel channel number of the first channel in the group to perform analysis on
		121	* @param coeffs array of pointers to the transformed coefficients
		122	* @param wi window information for the channels in the group
		123	*/
		124	void (analyze)(FFPsyContext ctx, int channel, const float *coeffs, const FFPsyWindowInfo wi);
		125
		126	void (end) (FFPsyContext apc);
		127	} FFPsyModel;
		128
		129	/**
		130	* Initialize psychoacoustic model.
		131	*
		132	* @param ctx model context
		133	* @param avctx codec context
		134	* @param num_lens number of possible frame lengths
		135	* @param bands scalefactor band lengths for all frame lengths
		136	* @param num_bands number of scalefactor bands for all frame lengths
		137	* @param num_groups number of channel groups
		138	* @param group_map array with # of channels in group - 1, for each group
		139	*
		140	* @return zero if successful, a negative value if not
		141	*/
		142	int ff_psy_init(FFPsyContext ctx, AVCodecContext avctx, int num_lens,
		143	const uint8_t *bands, const int num_bands,
		144	int num_groups, const uint8_t *group_map);
		145
		146	/**
		147	* Determine what group a channel belongs to.
		148	*
		149	* @param ctx psymodel context
		150	* @param channel channel to locate the group for
		151	*
		152	* @return pointer to the FFPsyChannelGroup this channel belongs to
		153	*/
		154	FFPsyChannelGroup ff_psy_find_group(FFPsyContext ctx, int channel);
		155
		156	/**
		157	* Cleanup model context at the end.
		158	*
		159	* @param ctx model context
		160	*/
		161	void ff_psy_end(FFPsyContext *ctx);
		162
		163
		164	/**************************************************************************
		165	* Audio preprocessing stuff. *
		166	* This should be moved into some audio filter eventually. *
		167	**************************************************************************/
		168	struct FFPsyPreprocessContext;
		169
		170	/**
		171	* psychoacoustic model audio preprocessing initialization
		172	*/
		173	struct FFPsyPreprocessContext ff_psy_preprocess_init(AVCodecContext avctx);
		174
		175	/**
		176	* Preprocess several channel in audio frame in order to compress it better.
		177	*
		178	* @param ctx preprocessing context
		179	* @param audio samples to be filtered (in place)
		180	* @param channels number of channel to preprocess
		181	*/
		182	void ff_psy_preprocess(struct FFPsyPreprocessContext ctx, float *audio, int channels);
		183
		184	/**
		185	* Cleanup audio preprocessing module.
		186	*/
		187	void ff_psy_preprocess_end(struct FFPsyPreprocessContext *ctx);
		188
		189	#endif /* AVCODEC_PSYMODEL_H */

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