include/share/replaygain_analysis.h

   1 /*
   2  *  ReplayGainAnalysis - analyzes input samples and give the recommended dB change
   3  *  Copyright (C) 2001 David Robinson and Glen Sawyer
   4  *
   5  *  This library is free software; you can redistribute it and/or
   6  *  modify it under the terms of the GNU Lesser General Public
   7  *  License as published by the Free Software Foundation; either
   8  *  version 2.1 of the License, or (at your option) any later version.
   9  *
  10  *  This library is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  *  Lesser General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU Lesser General Public
  16  *  License along with this library; if not, write to the Free Software
  17  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  18  *
  19  *  concept and filter values by David Robinson (David@Robinson.org)
  20  *    -- blame him if you think the idea is flawed
  21  *  coding by Glen Sawyer (glensawyer@hotmail.com) 442 N 700 E, Provo, UT 84606 USA
  22  *    -- blame him if you think this runs too slowly, or the coding is otherwise flawed
  23  *  minor cosmetic tweaks to integrate with FLAC by Josh Coalson
  24  *
  25  *  For an explanation of the concepts and the basic algorithms involved, go to:
  26  *    http://www.replaygain.org/
  27  */
  28
  29 #ifndef GAIN_ANALYSIS_H
  30 #define GAIN_ANALYSIS_H
  31
  32 #include <stddef.h>
  33
  34 #define GAIN_NOT_ENOUGH_SAMPLES  -24601
  35 #define GAIN_ANALYSIS_ERROR           0
  36 #define GAIN_ANALYSIS_OK              1
  37
  38 #define INIT_GAIN_ANALYSIS_ERROR      0
  39 #define INIT_GAIN_ANALYSIS_OK         1
  40
  41 #ifdef __cplusplus
  42 extern "C" {
  43 #endif
  44
  45 typedef float   flac_float_t;         /* Type used for filtering */
  46
  47 extern flac_float_t ReplayGainReferenceLoudness; /* in dB SPL, currently == 89.0 */
  48
  49 int     InitGainAnalysis ( long samplefreq );
  50 int     ValidGainFrequency ( long samplefreq );
  51 int     AnalyzeSamples   ( const flac_float_t* left_samples, const flac_float_t* right_samples, size_t num_samples, int num_channels );
  52 flac_float_t GetTitleGain     ( void );
  53 flac_float_t GetAlbumGain     ( void );
  54
  55 #ifdef __cplusplus
  56 }
  57 #endif
  58
  59 #endif /* GAIN_ANALYSIS_H */