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 */
60