/*

 *  ReplayGainAnalysis - analyzes input samples and give the recommended dB change

 *  Copyright (C) 2001 David Robinson and Glen Sawyer

 *

 *  This library 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.

 *

 *  This library 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 this library; if not, write to the Free Software

 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 *

 *  concept and filter values by David Robinson (David@Robinson.org)

 *    -- blame him if you think the idea is flawed

 *  coding by Glen Sawyer (mp3gain@hotmail.com) 735 W 255 N, Orem, UT 84057-4505 USA

 *    -- blame him if you think this runs too slowly, or the coding is otherwise flawed

 *

 *  For an explanation of the concepts and the basic algorithms involved, go to:

 *    http://www.replaygain.org/

 */

#ifndef GAIN_ANALYSIS_H

#define GAIN_ANALYSIS_H

#ifdef HAVE_INTTYPES_H

# include <inttypes.h>

#else

# ifdef HAVE_STDINT_H

#  include <stdint.h>

# endif

#endif

#ifdef __cplusplus

extern  "C" {

#endif

    typedef sample_t Float_t; /* Type used for filtering */

#define PINK_REF                64.82       /* 298640883795 */ /* calibration value for 89dB */

#define YULE_ORDER         10

#define BUTTER_ORDER        2

#define YULE_FILTER     filterYule

#define BUTTER_FILTER   filterButter

#define RMS_PERCENTILE      0.95 /* percentile which is louder than the proposed level */

#define MAX_SAMP_FREQ   48000L /* maximum allowed sample frequency [Hz] */

#define RMS_WINDOW_TIME_NUMERATOR    1L

#define RMS_WINDOW_TIME_DENOMINATOR 20L /* numerator / denominator = time slice size [s] */

#define STEPS_per_dB      100 /* Table entries per dB */

#define MAX_dB            120 /* Table entries for 0...MAX_dB (normal max. values are 70...80 dB) */

    enum { GAIN_NOT_ENOUGH_SAMPLES = -24601, GAIN_ANALYSIS_ERROR = 0, GAIN_ANALYSIS_OK =

            1, INIT_GAIN_ANALYSIS_ERROR = 0, INIT_GAIN_ANALYSIS_OK = 1

    };

    enum { MAX_ORDER = (BUTTER_ORDER > YULE_ORDER ? BUTTER_ORDER : YULE_ORDER)

            , MAX_SAMPLES_PER_WINDOW = ((MAX_SAMP_FREQ * RMS_WINDOW_TIME_NUMERATOR) / RMS_WINDOW_TIME_DENOMINATOR + 1) /* max. Samples per Time slice */

    };

    struct replaygain_data {

        Float_t linprebuf[MAX_ORDER * 2];

        Float_t *linpre;     /* left input samples, with pre-buffer */

        Float_t lstepbuf[MAX_SAMPLES_PER_WINDOW + MAX_ORDER];

        Float_t *lstep;      /* left "first step" (i.e. post first filter) samples */

        Float_t loutbuf[MAX_SAMPLES_PER_WINDOW + MAX_ORDER];

        Float_t *lout;       /* left "out" (i.e. post second filter) samples */

        Float_t rinprebuf[MAX_ORDER * 2];

        Float_t *rinpre;     /* right input samples ... */

        Float_t rstepbuf[MAX_SAMPLES_PER_WINDOW + MAX_ORDER];

        Float_t *rstep;

        Float_t routbuf[MAX_SAMPLES_PER_WINDOW + MAX_ORDER];

        Float_t *rout;

        long    sampleWindow; /* number of samples required to reach number of milliseconds required for RMS window */

        long    totsamp;

        double  lsum;

        double  rsum;

        int     freqindex;

        int     first;

        uint32_t A[STEPS_per_dB * MAX_dB];

        uint32_t B[STEPS_per_dB * MAX_dB];

    };

#ifndef replaygain_data_defined

#define replaygain_data_defined

    typedef struct replaygain_data replaygain_t;

#endif

    int     InitGainAnalysis(replaygain_t * rgData, long samplefreq);

    int     AnalyzeSamples(replaygain_t * rgData, const Float_t * left_samples,

                           const Float_t * right_samples, size_t num_samples, int num_channels);

    Float_t GetTitleGain(replaygain_t * rgData);

#ifdef __cplusplus

}

#endif

#endif                       /* GAIN_ANALYSIS_H */