libavcodec/ac3.h - nest-android-app/ffmpeg - Git at Google

 /*
  * Common code between the AC-3 encoder and decoder
  * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */

 /**
  * @file
  * Common code between the AC-3 encoder and decoder.
  */

 #ifndef AVCODEC_AC3_H
 #define AVCODEC_AC3_H

 #define AC3_MAX_CODED_FRAME_SIZE 3840 /* in bytes */
 #define AC3_MAX_CHANNELS 7            /**< maximum number of channels, including coupling channel */
 #define CPL_CH 0                      /**< coupling channel index */

 #define AC3_MAX_COEFS   256
 #define AC3_BLOCK_SIZE  256
 #define AC3_MAX_BLOCKS    6
 #define AC3_FRAME_SIZE (AC3_MAX_BLOCKS * 256)
 #define AC3_WINDOW_SIZE (AC3_BLOCK_SIZE * 2)
 #define AC3_CRITICAL_BANDS 50
 #define AC3_MAX_CPL_BANDS  18

 #include "libavutil/opt.h"
 #include "avcodec.h"
 #include "ac3tab.h"

 /* exponent encoding strategy */
 #define EXP_REUSE 0
 #define EXP_NEW   1

 #define EXP_D15   1
 #define EXP_D25   2
 #define EXP_D45   3

 #ifndef USE_FIXED
 #define USE_FIXED 0
 #endif

 #if USE_FIXED

 #define FFT_FLOAT 0

 #define FIXR(a)                 ((int)((a) * 0 + 0.5))
 #define FIXR12(a)               ((int)((a) * 4096 + 0.5))
 #define FIXR15(a)               ((int)((a) * 32768 + 0.5))
 #define ROUND15(x)              ((x) + 16384) >> 15

 #define AC3_RENAME(x)           x ## _fixed
 #define AC3_NORM(norm)          (1<<24)/(norm)
 #define AC3_MUL(a,b)            ((((int64_t) (a)) * (b))>>12)
 #define AC3_RANGE(x)            ((x)|(((x)&128)<<1))
 #define AC3_HEAVY_RANGE(x)      ((x)<<1)
 #define AC3_DYNAMIC_RANGE(x)    (x)
 #define AC3_SPX_BLEND(x)        (x)
 #define AC3_DYNAMIC_RANGE1      0

 typedef int                     INTFLOAT;
 typedef int16_t                 SHORTFLOAT;

 #else /* USE_FIXED */

 #define FIXR(x)                 ((float)(x))
 #define FIXR12(x)               ((float)(x))
 #define FIXR15(x)               ((float)(x))
 #define ROUND15(x)              (x)

 #define AC3_RENAME(x)           x
 #define AC3_NORM(norm)          (1.0f/(norm))
 #define AC3_MUL(a,b)            ((a) * (b))
 #define AC3_RANGE(x)            (dynamic_range_tab[(x)])
 #define AC3_HEAVY_RANGE(x)      (heavy_dynamic_range_tab[(x)])
 #define AC3_DYNAMIC_RANGE(x)    (powf(x,  s->drc_scale))
 #define AC3_SPX_BLEND(x)        (x)* (1.0f/32)
 #define AC3_DYNAMIC_RANGE1      1.0f

 typedef float                   INTFLOAT;
 typedef float                   SHORTFLOAT;

 #endif /* USE_FIXED */

 #define AC3_LEVEL(x)            ROUND15((x) * FIXR15(M_SQRT1_2))

 /* pre-defined gain values */
 #define LEVEL_PLUS_3DB          M_SQRT2
 #define LEVEL_PLUS_1POINT5DB    1.1892071150027209
 #define LEVEL_MINUS_1POINT5DB   0.8408964152537145
 #define LEVEL_MINUS_3DB         M_SQRT1_2
 #define LEVEL_MINUS_4POINT5DB   0.5946035575013605
 #define LEVEL_MINUS_6DB         0.5000000000000000
 #define LEVEL_MINUS_9DB         0.3535533905932738
 #define LEVEL_ZERO              0.0000000000000000
 #define LEVEL_ONE               1.0000000000000000

 /** Delta bit allocation strategy */
 typedef enum {
     DBA_REUSE = 0,
     DBA_NEW,
     DBA_NONE,
     DBA_RESERVED
 } AC3DeltaStrategy;

 /** Channel mode (audio coding mode) */
 typedef enum {
     AC3_CHMODE_DUALMONO = 0,
     AC3_CHMODE_MONO,
     AC3_CHMODE_STEREO,
     AC3_CHMODE_3F,
     AC3_CHMODE_2F1R,
     AC3_CHMODE_3F1R,
     AC3_CHMODE_2F2R,
     AC3_CHMODE_3F2R
 } AC3ChannelMode;

 /** Dolby Surround mode */
 typedef enum AC3DolbySurroundMode {
     AC3_DSURMOD_NOTINDICATED = 0,
     AC3_DSURMOD_OFF,
     AC3_DSURMOD_ON,
     AC3_DSURMOD_RESERVED
 } AC3DolbySurroundMode;

 /** Dolby Surround EX mode */
 typedef enum AC3DolbySurroundEXMode {
     AC3_DSUREXMOD_NOTINDICATED = 0,
     AC3_DSUREXMOD_OFF,
     AC3_DSUREXMOD_ON,
     AC3_DSUREXMOD_PLIIZ
 } AC3DolbySurroundEXMode;

 /** Dolby Headphone mode */
 typedef enum AC3DolbyHeadphoneMode {
     AC3_DHEADPHONMOD_NOTINDICATED = 0,
     AC3_DHEADPHONMOD_OFF,
     AC3_DHEADPHONMOD_ON,
     AC3_DHEADPHONMOD_RESERVED
 } AC3DolbyHeadphoneMode;

 /** Preferred Stereo Downmix mode */
 typedef enum AC3PreferredStereoDownmixMode {
     AC3_DMIXMOD_NOTINDICATED = 0,
     AC3_DMIXMOD_LTRT,
     AC3_DMIXMOD_LORO,
     AC3_DMIXMOD_DPLII // reserved value in A/52, but used by encoders to indicate DPL2
 } AC3PreferredStereoDownmixMode;

 typedef struct AC3BitAllocParameters {
     int sr_code;
     int sr_shift;
     int slow_gain, slow_decay, fast_decay, db_per_bit, floor;
     int cpl_fast_leak, cpl_slow_leak;
 } AC3BitAllocParameters;

 /**
  * @struct AC3HeaderInfo
  * Coded AC-3 header values up to the lfeon element, plus derived values.
  */
 typedef struct AC3HeaderInfo {
     /** @name Coded elements
      * @{
      */
     uint16_t sync_word;
     uint16_t crc1;
     uint8_t sr_code;
     uint8_t bitstream_id;
     uint8_t bitstream_mode;
     uint8_t channel_mode;
     uint8_t lfe_on;
     uint8_t frame_type;
     int substreamid;                        ///< substream identification
     int center_mix_level;                   ///< Center mix level index
     int surround_mix_level;                 ///< Surround mix level index
     uint16_t channel_map;
     int num_blocks;                         ///< number of audio blocks
     int dolby_surround_mode;
     /** @} */

     /** @name Derived values
      * @{
      */
     uint8_t sr_shift;
     uint16_t sample_rate;
     uint32_t bit_rate;
     uint8_t channels;
     uint16_t frame_size;
     uint64_t channel_layout;
     /** @} */
 } AC3HeaderInfo;

 typedef enum {
     EAC3_FRAME_TYPE_INDEPENDENT = 0,
     EAC3_FRAME_TYPE_DEPENDENT,
     EAC3_FRAME_TYPE_AC3_CONVERT,
     EAC3_FRAME_TYPE_RESERVED
 } EAC3FrameType;

 void ff_ac3_common_init(void);

 /**
  * Calculate the log power-spectral density of the input signal.
  * This gives a rough estimate of signal power in the frequency domain by using
  * the spectral envelope (exponents).  The psd is also separately grouped
  * into critical bands for use in the calculating the masking curve.
  * 128 units in psd = -6 dB.  The dbknee parameter in AC3BitAllocParameters
  * determines the reference level.
  *
  * @param[in]  exp        frequency coefficient exponents
  * @param[in]  start      starting bin location
  * @param[in]  end        ending bin location
  * @param[out] psd        signal power for each frequency bin
  * @param[out] band_psd   signal power for each critical band
  */
 void ff_ac3_bit_alloc_calc_psd(int8_t *exp, int start, int end, int16_t *psd,
                                int16_t *band_psd);

 /**
  * Calculate the masking curve.
  * First, the excitation is calculated using parameters in s and the signal
  * power in each critical band.  The excitation is compared with a predefined
  * hearing threshold table to produce the masking curve.  If delta bit
  * allocation information is provided, it is used for adjusting the masking
  * curve, usually to give a closer match to a better psychoacoustic model.
  *
  * @param[in]  s            adjustable bit allocation parameters
  * @param[in]  band_psd     signal power for each critical band
  * @param[in]  start        starting bin location
  * @param[in]  end          ending bin location
  * @param[in]  fast_gain    fast gain (estimated signal-to-mask ratio)
  * @param[in]  is_lfe       whether or not the channel being processed is the LFE
  * @param[in]  dba_mode     delta bit allocation mode (none, reuse, or new)
  * @param[in]  dba_nsegs    number of delta segments
  * @param[in]  dba_offsets  location offsets for each segment
  * @param[in]  dba_lengths  length of each segment
  * @param[in]  dba_values   delta bit allocation for each segment
  * @param[out] mask         calculated masking curve
  * @return returns 0 for success, non-zero for error
  */
 int ff_ac3_bit_alloc_calc_mask(AC3BitAllocParameters *s, int16_t *band_psd,
                                int start, int end, int fast_gain, int is_lfe,
                                int dba_mode, int dba_nsegs, uint8_t *dba_offsets,
                                uint8_t *dba_lengths, uint8_t *dba_values,
                                int16_t *mask);

 #endif /* AVCODEC_AC3_H */
	/*
	* Common code between the AC-3 encoder and decoder
	* Copyright (c) 2000, 2001, 2002 Fabrice Bellard
	*
	* This file is part of FFmpeg.
	*
	* FFmpeg is free software; you can redistribute it and/or
	* modify it under the terms of the GNU Lesser General Public
	* License as published by the Free Software Foundation; either
	* version 2.1 of the License, or (at your option) any later version.
	*
	* FFmpeg is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	* Lesser General Public License for more details.
	*
	* You should have received a copy of the GNU Lesser General Public
	* License along with FFmpeg; if not, write to the Free Software
	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	*/

	/**
	* @file
	* Common code between the AC-3 encoder and decoder.
	*/

	#ifndef AVCODEC_AC3_H
	#define AVCODEC_AC3_H

	#define AC3_MAX_CODED_FRAME_SIZE 3840 /* in bytes */
	#define AC3_MAX_CHANNELS 7 /*< maximum number of channels, including coupling channel /
	#define CPL_CH 0 /*< coupling channel index /

	#define AC3_MAX_COEFS 256
	#define AC3_BLOCK_SIZE 256
	#define AC3_MAX_BLOCKS 6
	#define AC3_FRAME_SIZE (AC3_MAX_BLOCKS * 256)
	#define AC3_WINDOW_SIZE (AC3_BLOCK_SIZE * 2)
	#define AC3_CRITICAL_BANDS 50
	#define AC3_MAX_CPL_BANDS 18

	#include "libavutil/opt.h"
	#include "avcodec.h"
	#include "ac3tab.h"

	/* exponent encoding strategy */
	#define EXP_REUSE 0
	#define EXP_NEW 1

	#define EXP_D15 1
	#define EXP_D25 2
	#define EXP_D45 3

	#ifndef USE_FIXED
	#define USE_FIXED 0
	#endif

	#if USE_FIXED

	#define FFT_FLOAT 0

	#define FIXR(a) ((int)((a) * 0 + 0.5))
	#define FIXR12(a) ((int)((a) * 4096 + 0.5))
	#define FIXR15(a) ((int)((a) * 32768 + 0.5))
	#define ROUND15(x) ((x) + 16384) >> 15

	#define AC3_RENAME(x) x ## _fixed
	#define AC3_NORM(norm) (1<<24)/(norm)
	#define AC3_MUL(a,b) ((((int64_t) (a)) * (b))>>12)
	#define AC3_RANGE(x) ((x)\|(((x)&128)<<1))
	#define AC3_HEAVY_RANGE(x) ((x)<<1)
	#define AC3_DYNAMIC_RANGE(x) (x)
	#define AC3_SPX_BLEND(x) (x)
	#define AC3_DYNAMIC_RANGE1 0

	typedef int INTFLOAT;
	typedef int16_t SHORTFLOAT;

	#else /* USE_FIXED */

	#define FIXR(x) ((float)(x))
	#define FIXR12(x) ((float)(x))
	#define FIXR15(x) ((float)(x))
	#define ROUND15(x) (x)

	#define AC3_RENAME(x) x
	#define AC3_NORM(norm) (1.0f/(norm))
	#define AC3_MUL(a,b) ((a) * (b))
	#define AC3_RANGE(x) (dynamic_range_tab[(x)])
	#define AC3_HEAVY_RANGE(x) (heavy_dynamic_range_tab[(x)])
	#define AC3_DYNAMIC_RANGE(x) (powf(x, s->drc_scale))
	#define AC3_SPX_BLEND(x) (x)* (1.0f/32)
	#define AC3_DYNAMIC_RANGE1 1.0f

	typedef float INTFLOAT;
	typedef float SHORTFLOAT;

	#endif /* USE_FIXED */

	#define AC3_LEVEL(x) ROUND15((x) * FIXR15(M_SQRT1_2))

	/* pre-defined gain values */
	#define LEVEL_PLUS_3DB M_SQRT2
	#define LEVEL_PLUS_1POINT5DB 1.1892071150027209
	#define LEVEL_MINUS_1POINT5DB 0.8408964152537145
	#define LEVEL_MINUS_3DB M_SQRT1_2
	#define LEVEL_MINUS_4POINT5DB 0.5946035575013605
	#define LEVEL_MINUS_6DB 0.5000000000000000
	#define LEVEL_MINUS_9DB 0.3535533905932738
	#define LEVEL_ZERO 0.0000000000000000
	#define LEVEL_ONE 1.0000000000000000

	/** Delta bit allocation strategy */
	typedef enum {
	DBA_REUSE = 0,
	DBA_NEW,
	DBA_NONE,
	DBA_RESERVED
	} AC3DeltaStrategy;

	/** Channel mode (audio coding mode) */
	typedef enum {
	AC3_CHMODE_DUALMONO = 0,
	AC3_CHMODE_MONO,
	AC3_CHMODE_STEREO,
	AC3_CHMODE_3F,
	AC3_CHMODE_2F1R,
	AC3_CHMODE_3F1R,
	AC3_CHMODE_2F2R,
	AC3_CHMODE_3F2R
	} AC3ChannelMode;

	/** Dolby Surround mode */
	typedef enum AC3DolbySurroundMode {
	AC3_DSURMOD_NOTINDICATED = 0,
	AC3_DSURMOD_OFF,
	AC3_DSURMOD_ON,
	AC3_DSURMOD_RESERVED
	} AC3DolbySurroundMode;

	/** Dolby Surround EX mode */
	typedef enum AC3DolbySurroundEXMode {
	AC3_DSUREXMOD_NOTINDICATED = 0,
	AC3_DSUREXMOD_OFF,
	AC3_DSUREXMOD_ON,
	AC3_DSUREXMOD_PLIIZ
	} AC3DolbySurroundEXMode;

	/** Dolby Headphone mode */
	typedef enum AC3DolbyHeadphoneMode {
	AC3_DHEADPHONMOD_NOTINDICATED = 0,
	AC3_DHEADPHONMOD_OFF,
	AC3_DHEADPHONMOD_ON,
	AC3_DHEADPHONMOD_RESERVED
	} AC3DolbyHeadphoneMode;

	/** Preferred Stereo Downmix mode */
	typedef enum AC3PreferredStereoDownmixMode {
	AC3_DMIXMOD_NOTINDICATED = 0,
	AC3_DMIXMOD_LTRT,
	AC3_DMIXMOD_LORO,
	AC3_DMIXMOD_DPLII // reserved value in A/52, but used by encoders to indicate DPL2
	} AC3PreferredStereoDownmixMode;

	typedef struct AC3BitAllocParameters {
	int sr_code;
	int sr_shift;
	int slow_gain, slow_decay, fast_decay, db_per_bit, floor;
	int cpl_fast_leak, cpl_slow_leak;
	} AC3BitAllocParameters;

	/**
	* @struct AC3HeaderInfo
	* Coded AC-3 header values up to the lfeon element, plus derived values.
	*/
	typedef struct AC3HeaderInfo {
	/** @name Coded elements
	* @{
	*/
	uint16_t sync_word;
	uint16_t crc1;
	uint8_t sr_code;
	uint8_t bitstream_id;
	uint8_t bitstream_mode;
	uint8_t channel_mode;
	uint8_t lfe_on;
	uint8_t frame_type;
	int substreamid; ///< substream identification
	int center_mix_level; ///< Center mix level index
	int surround_mix_level; ///< Surround mix level index
	uint16_t channel_map;
	int num_blocks; ///< number of audio blocks
	int dolby_surround_mode;
	/** @} */

	/** @name Derived values
	* @{
	*/
	uint8_t sr_shift;
	uint16_t sample_rate;
	uint32_t bit_rate;
	uint8_t channels;
	uint16_t frame_size;
	uint64_t channel_layout;
	/** @} */
	} AC3HeaderInfo;

	typedef enum {
	EAC3_FRAME_TYPE_INDEPENDENT = 0,
	EAC3_FRAME_TYPE_DEPENDENT,
	EAC3_FRAME_TYPE_AC3_CONVERT,
	EAC3_FRAME_TYPE_RESERVED
	} EAC3FrameType;

	void ff_ac3_common_init(void);

	/**
	* Calculate the log power-spectral density of the input signal.
	* This gives a rough estimate of signal power in the frequency domain by using
	* the spectral envelope (exponents). The psd is also separately grouped
	* into critical bands for use in the calculating the masking curve.
	* 128 units in psd = -6 dB. The dbknee parameter in AC3BitAllocParameters
	* determines the reference level.
	*
	* @param[in] exp frequency coefficient exponents
	* @param[in] start starting bin location
	* @param[in] end ending bin location
	* @param[out] psd signal power for each frequency bin
	* @param[out] band_psd signal power for each critical band
	*/
	void ff_ac3_bit_alloc_calc_psd(int8_t exp, int start, int end, int16_t psd,
	int16_t *band_psd);

	/**
	* Calculate the masking curve.
	* First, the excitation is calculated using parameters in s and the signal
	* power in each critical band. The excitation is compared with a predefined
	* hearing threshold table to produce the masking curve. If delta bit
	* allocation information is provided, it is used for adjusting the masking
	* curve, usually to give a closer match to a better psychoacoustic model.
	*
	* @param[in] s adjustable bit allocation parameters
	* @param[in] band_psd signal power for each critical band
	* @param[in] start starting bin location
	* @param[in] end ending bin location
	* @param[in] fast_gain fast gain (estimated signal-to-mask ratio)
	* @param[in] is_lfe whether or not the channel being processed is the LFE
	* @param[in] dba_mode delta bit allocation mode (none, reuse, or new)
	* @param[in] dba_nsegs number of delta segments
	* @param[in] dba_offsets location offsets for each segment
	* @param[in] dba_lengths length of each segment
	* @param[in] dba_values delta bit allocation for each segment
	* @param[out] mask calculated masking curve
	* @return returns 0 for success, non-zero for error
	*/
	int ff_ac3_bit_alloc_calc_mask(AC3BitAllocParameters s, int16_t band_psd,
	int start, int end, int fast_gain, int is_lfe,
	int dba_mode, int dba_nsegs, uint8_t *dba_offsets,
	uint8_t dba_lengths, uint8_t dba_values,
	int16_t *mask);

	#endif /* AVCODEC_AC3_H */