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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 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 (mp3gain@hotmail.com) 735 W 255 N, Orem, UT 84057-4505 USA 22 * -- blame him if you think this runs too slowly, or the coding is otherwise flawed 23 * 24 * For an explanation of the concepts and the basic algorithms involved, go to: 25 * http://www.replaygain.org/ 26 */ 27 28 #ifndef GAIN_ANALYSIS_H 29 #define GAIN_ANALYSIS_H 30 31 #ifdef HAVE_INTTYPES_H 32 # include <inttypes.h> 33 #else 34 # ifdef HAVE_STDINT_H 35 # include <stdint.h> 36 # endif 37 #endif 38 39 #ifdef __cplusplus 40 extern "C" { 41 #endif 42 43 44 typedef sample_t Float_t; /* Type used for filtering */ 45 46 47 #define PINK_REF 64.82 /* 298640883795 */ /* calibration value for 89dB */ 48 49 50 #define YULE_ORDER 10 51 #define BUTTER_ORDER 2 52 #define YULE_FILTER filterYule 53 #define BUTTER_FILTER filterButter 54 #define RMS_PERCENTILE 0.95 /* percentile which is louder than the proposed level */ 55 #define MAX_SAMP_FREQ 48000L /* maximum allowed sample frequency [Hz] */ 56 #define RMS_WINDOW_TIME_NUMERATOR 1L 57 #define RMS_WINDOW_TIME_DENOMINATOR 20L /* numerator / denominator = time slice size [s] */ 58 #define STEPS_per_dB 100 /* Table entries per dB */ 59 #define MAX_dB 120 /* Table entries for 0...MAX_dB (normal max. values are 70...80 dB) */ 60 61 enum { GAIN_NOT_ENOUGH_SAMPLES = -24601, GAIN_ANALYSIS_ERROR = 0, GAIN_ANALYSIS_OK = 62 1, INIT_GAIN_ANALYSIS_ERROR = 0, INIT_GAIN_ANALYSIS_OK = 1 63 }; 64 65 enum { MAX_ORDER = (BUTTER_ORDER > YULE_ORDER ? BUTTER_ORDER : YULE_ORDER) 66 , MAX_SAMPLES_PER_WINDOW = ((MAX_SAMP_FREQ * RMS_WINDOW_TIME_NUMERATOR) / RMS_WINDOW_TIME_DENOMINATOR + 1) /* max. Samples per Time slice */ 67 }; 68 69 struct replaygain_data { 70 Float_t linprebuf[MAX_ORDER * 2]; 71 Float_t *linpre; /* left input samples, with pre-buffer */ 72 Float_t lstepbuf[MAX_SAMPLES_PER_WINDOW + MAX_ORDER]; 73 Float_t *lstep; /* left "first step" (i.e. post first filter) samples */ 74 Float_t loutbuf[MAX_SAMPLES_PER_WINDOW + MAX_ORDER]; 75 Float_t *lout; /* left "out" (i.e. post second filter) samples */ 76 Float_t rinprebuf[MAX_ORDER * 2]; 77 Float_t *rinpre; /* right input samples ... */ 78 Float_t rstepbuf[MAX_SAMPLES_PER_WINDOW + MAX_ORDER]; 79 Float_t *rstep; 80 Float_t routbuf[MAX_SAMPLES_PER_WINDOW + MAX_ORDER]; 81 Float_t *rout; 82 long sampleWindow; /* number of samples required to reach number of milliseconds required for RMS window */ 83 long totsamp; 84 double lsum; 85 double rsum; 86 int freqindex; 87 int first; 88 uint32_t A[STEPS_per_dB * MAX_dB]; 89 uint32_t B[STEPS_per_dB * MAX_dB]; 90 91 }; 92 #ifndef replaygain_data_defined 93 #define replaygain_data_defined 94 typedef struct replaygain_data replaygain_t; 95 #endif 96 97 98 99 100 int InitGainAnalysis(replaygain_t * rgData, long samplefreq); 101 int AnalyzeSamples(replaygain_t * rgData, const Float_t * left_samples, 102 const Float_t * right_samples, size_t num_samples, int num_channels); 103 Float_t GetTitleGain(replaygain_t * rgData); 104 105 106 #ifdef __cplusplus 107 } 108 #endif 109 #endif /* GAIN_ANALYSIS_H */ 110