/*

  * 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)      (ff_ac3_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 */