110 lines
4.1 KiB
C
110 lines
4.1 KiB
C
/*
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* ReplayGainAnalysis - analyzes input samples and give the recommended dB change
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* Copyright (C) 2001 David Robinson and Glen Sawyer
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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* concept and filter values by David Robinson (David@Robinson.org)
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* -- blame him if you think the idea is flawed
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* coding by Glen Sawyer (mp3gain@hotmail.com) 735 W 255 N, Orem, UT 84057-4505 USA
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* -- blame him if you think this runs too slowly, or the coding is otherwise flawed
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*
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* For an explanation of the concepts and the basic algorithms involved, go to:
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* http://www.replaygain.org/
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*/
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#ifndef GAIN_ANALYSIS_H
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#define GAIN_ANALYSIS_H
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#ifdef HAVE_INTTYPES_H
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# include <inttypes.h>
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#else
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# ifdef HAVE_STDINT_H
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# include <stdint.h>
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# endif
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#endif
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#ifdef __cplusplus
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extern "C" {
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#endif
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typedef sample_t Float_t; /* Type used for filtering */
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#define PINK_REF 64.82 /* 298640883795 */ /* calibration value for 89dB */
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#define YULE_ORDER 10
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#define BUTTER_ORDER 2
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#define YULE_FILTER filterYule
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#define BUTTER_FILTER filterButter
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#define RMS_PERCENTILE 0.95 /* percentile which is louder than the proposed level */
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#define MAX_SAMP_FREQ 48000L /* maximum allowed sample frequency [Hz] */
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#define RMS_WINDOW_TIME_NUMERATOR 1L
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#define RMS_WINDOW_TIME_DENOMINATOR 20L /* numerator / denominator = time slice size [s] */
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#define STEPS_per_dB 100 /* Table entries per dB */
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#define MAX_dB 120 /* Table entries for 0...MAX_dB (normal max. values are 70...80 dB) */
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enum { GAIN_NOT_ENOUGH_SAMPLES = -24601, GAIN_ANALYSIS_ERROR = 0, GAIN_ANALYSIS_OK =
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1, INIT_GAIN_ANALYSIS_ERROR = 0, INIT_GAIN_ANALYSIS_OK = 1
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};
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enum { MAX_ORDER = (BUTTER_ORDER > YULE_ORDER ? BUTTER_ORDER : YULE_ORDER)
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, MAX_SAMPLES_PER_WINDOW = ((MAX_SAMP_FREQ * RMS_WINDOW_TIME_NUMERATOR) / RMS_WINDOW_TIME_DENOMINATOR + 1) /* max. Samples per Time slice */
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};
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struct replaygain_data {
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Float_t linprebuf[MAX_ORDER * 2];
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Float_t *linpre; /* left input samples, with pre-buffer */
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Float_t lstepbuf[MAX_SAMPLES_PER_WINDOW + MAX_ORDER];
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Float_t *lstep; /* left "first step" (i.e. post first filter) samples */
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Float_t loutbuf[MAX_SAMPLES_PER_WINDOW + MAX_ORDER];
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Float_t *lout; /* left "out" (i.e. post second filter) samples */
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Float_t rinprebuf[MAX_ORDER * 2];
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Float_t *rinpre; /* right input samples ... */
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Float_t rstepbuf[MAX_SAMPLES_PER_WINDOW + MAX_ORDER];
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Float_t *rstep;
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Float_t routbuf[MAX_SAMPLES_PER_WINDOW + MAX_ORDER];
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Float_t *rout;
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long sampleWindow; /* number of samples required to reach number of milliseconds required for RMS window */
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long totsamp;
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double lsum;
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double rsum;
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int freqindex;
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int first;
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uint32_t A[STEPS_per_dB * MAX_dB];
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uint32_t B[STEPS_per_dB * MAX_dB];
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};
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#ifndef replaygain_data_defined
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#define replaygain_data_defined
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typedef struct replaygain_data replaygain_t;
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#endif
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int InitGainAnalysis(replaygain_t * rgData, long samplefreq);
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int AnalyzeSamples(replaygain_t * rgData, const Float_t * left_samples,
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const Float_t * right_samples, size_t num_samples, int num_channels);
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Float_t GetTitleGain(replaygain_t * rgData);
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#ifdef __cplusplus
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}
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#endif
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#endif /* GAIN_ANALYSIS_H */
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