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/*
* 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
* original coding by Glen Sawyer (glensawyer@hotmail.com)
* -- blame him if you think this runs too slowly, or the coding is otherwise flawed
*
* lots of code improvements by Frank Klemm ( http://www.uni-jena.de/~pfk/mpp/ )
* -- credit him for all the _good_ programming ;)
*
*
* For an explanation of the concepts and the basic algorithms involved, go to:
* http://www.replaygain.org/
*/
/*
* Here's the deal. Call
*
* InitGainAnalysis ( long samplefreq );
*
* to initialize everything. Call
*
* AnalyzeSamples ( const Float_t* left_samples,
* const Float_t* right_samples,
* size_t num_samples,
* int num_channels );
*
* as many times as you want, with as many or as few samples as you want.
* If mono, pass the sample buffer in through left_samples, leave
* right_samples NULL, and make sure num_channels = 1.
*
* GetTitleGain()
*
* will return the recommended dB level change for all samples analyzed
* SINCE THE LAST TIME you called GetTitleGain() OR InitGainAnalysis().
*
* GetAlbumGain()
*
* will return the recommended dB level change for all samples analyzed
* since InitGainAnalysis() was called and finalized with GetTitleGain().
*
* Pseudo-code to process an album:
*
* Float_t l_samples [4096];
* Float_t r_samples [4096];
* size_t num_samples;
* unsigned int num_songs;
* unsigned int i;
*
* InitGainAnalysis ( 44100 );
* for ( i = 1; i <= num_songs; i++ ) {
* while ( ( num_samples = getSongSamples ( song[i], left_samples, right_samples ) ) > 0 )
* AnalyzeSamples ( left_samples, right_samples, num_samples, 2 );
* fprintf ("Recommended dB change for song %2d: %+6.2f dB\n", i, GetTitleGain() );
* }
* fprintf ("Recommended dB change for whole album: %+6.2f dB\n", GetAlbumGain() );
*/
/*
* So here's the main source of potential code confusion:
*
* The filters applied to the incoming samples are IIR filters,
* meaning they rely on up to <filter order> number of previous samples
* AND up to <filter order> number of previous filtered samples.
*
* I set up the AnalyzeSamples routine to minimize memory usage and interface
* complexity. The speed isn't compromised too much (I don't think), but the
* internal complexity is higher than it should be for such a relatively
* simple routine.
*
* Optimization/clarity suggestions are welcome.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include "gain_analysis.h"
typedef unsigned short Uint16_t;
typedef signed short Int16_t;
typedef unsigned int Uint32_t;
typedef signed int Int32_t;
#define YULE_ORDER 10
#define BUTTER_ORDER 2
#define RMS_PERCENTILE 0.95 /* percentile which is louder than the proposed level */
#define MAX_SAMP_FREQ 48000. /* maximum allowed sample frequency [Hz] */
#define RMS_WINDOW_TIME 0.050 /* 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) */
#define MAX_ORDER (BUTTER_ORDER > YULE_ORDER ? BUTTER_ORDER : YULE_ORDER)
#define MAX_SAMPLES_PER_WINDOW (size_t) (MAX_SAMP_FREQ * RMS_WINDOW_TIME + 1) /* max. Samples per Time slice */
#define PINK_REF 64.82 /* 298640883795 */ /* calibration value */
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;
unsigned int sampleWindow; /* number of samples required to reach number of milliseconds required for RMS window */
unsigned long totsamp;
double lsum;
double rsum;
int freqindex;
int first;
static Uint32_t A [(size_t)(STEPS_per_dB * MAX_dB)];
static Uint32_t B [(size_t)(STEPS_per_dB * MAX_dB)];
/* for each filter:
[0] 48 kHz, [1] 44.1 kHz, [2] 32 kHz, [3] 24 kHz, [4] 22050 Hz, [5] 16 kHz, [6] 12 kHz, [7] is 11025 Hz, [8] 8 kHz */
#ifdef WIN32
#pragma warning ( disable : 4305 )
#endif
const Float_t AYule [9] [11] = {
{ 1., -3.84664617118067, 7.81501653005538,-11.34170355132042, 13.05504219327545,-12.28759895145294, 9.48293806319790, -5.87257861775999, 2.75465861874613, -0.86984376593551, 0.13919314567432 },
{ 1., -3.47845948550071, 6.36317777566148, -8.54751527471874, 9.47693607801280, -8.81498681370155, 6.85401540936998, -4.39470996079559, 2.19611684890774, -0.75104302451432, 0.13149317958808 },
{ 1., -2.37898834973084, 2.84868151156327, -2.64577170229825, 2.23697657451713, -1.67148153367602, 1.00595954808547, -0.45953458054983, 0.16378164858596, -0.05032077717131, 0.02347897407020 },
{ 1., -1.61273165137247, 1.07977492259970, -0.25656257754070, -0.16276719120440, -0.22638893773906, 0.39120800788284, -0.22138138954925, 0.04500235387352, 0.02005851806501, 0.00302439095741 },
{ 1., -1.49858979367799, 0.87350271418188, 0.12205022308084, -0.80774944671438, 0.47854794562326, -0.12453458140019, -0.04067510197014, 0.08333755284107, -0.04237348025746, 0.02977207319925 },
{ 1., -0.62820619233671, 0.29661783706366, -0.37256372942400, 0.00213767857124, -0.42029820170918, 0.22199650564824, 0.00613424350682, 0.06747620744683, 0.05784820375801, 0.03222754072173 },
{ 1., -1.04800335126349, 0.29156311971249, -0.26806001042947, 0.00819999645858, 0.45054734505008, -0.33032403314006, 0.06739368333110, -0.04784254229033, 0.01639907836189, 0.01807364323573 },
{ 1., -0.51035327095184, -0.31863563325245, -0.20256413484477, 0.14728154134330, 0.38952639978999, -0.23313271880868, -0.05246019024463, -0.02505961724053, 0.02442357316099, 0.01818801111503 },
{ 1., -0.25049871956020, -0.43193942311114, -0.03424681017675, -0.04678328784242, 0.26408300200955, 0.15113130533216, -0.17556493366449, -0.18823009262115, 0.05477720428674, 0.04704409688120 }
};
const Float_t BYule [9] [11] = {
{ 0.03857599435200, -0.02160367184185, -0.00123395316851, -0.00009291677959, -0.01655260341619, 0.02161526843274, -0.02074045215285, 0.00594298065125, 0.00306428023191, 0.00012025322027, 0.00288463683916 },
{ 0.05418656406430, -0.02911007808948, -0.00848709379851, -0.00851165645469, -0.00834990904936, 0.02245293253339, -0.02596338512915, 0.01624864962975, -0.00240879051584, 0.00674613682247, -0.00187763777362 },
{ 0.15457299681924, -0.09331049056315, -0.06247880153653, 0.02163541888798, -0.05588393329856, 0.04781476674921, 0.00222312597743, 0.03174092540049, -0.01390589421898, 0.00651420667831, -0.00881362733839 },
{ 0.30296907319327, -0.22613988682123, -0.08587323730772, 0.03282930172664, -0.00915702933434, -0.02364141202522, -0.00584456039913, 0.06276101321749, -0.00000828086748, 0.00205861885564, -0.02950134983287 },
{ 0.33642304856132, -0.25572241425570, -0.11828570177555, 0.11921148675203, -0.07834489609479, -0.00469977914380, -0.00589500224440, 0.05724228140351, 0.00832043980773, -0.01635381384540, -0.01760176568150 },
{ 0.44915256608450, -0.14351757464547, -0.22784394429749, -0.01419140100551, 0.04078262797139, -0.12398163381748, 0.04097565135648, 0.10478503600251, -0.01863887810927, -0.03193428438915, 0.00541907748707 },
{ 0.56619470757641, -0.75464456939302, 0.16242137742230, 0.16744243493672, -0.18901604199609, 0.30931782841830, -0.27562961986224, 0.00647310677246, 0.08647503780351, -0.03788984554840, -0.00588215443421 },
{ 0.58100494960553, -0.53174909058578, -0.14289799034253, 0.17520704835522, 0.02377945217615, 0.15558449135573, -0.25344790059353, 0.01628462406333, 0.06920467763959, -0.03721611395801, -0.00749618797172 },
{ 0.53648789255105, -0.42163034350696, -0.00275953611929, 0.04267842219415, -0.10214864179676, 0.14590772289388, -0.02459864859345, -0.11202315195388, -0.04060034127000, 0.04788665548180, -0.02217936801134 }
};
const Float_t AButter [9] [3] = {
{ 1., -1.97223372919527, 0.97261396931306 },
{ 1., -1.96977855582618, 0.97022847566350 },
{ 1., -1.95835380975398, 0.95920349965459 },
{ 1., -1.95002759149878, 0.95124613669835 },
{ 1., -1.94561023566527, 0.94705070426118 },
{ 1., -1.92783286977036, 0.93034775234268 },
{ 1., -1.91858953033784, 0.92177618768381 },
{ 1., -1.91542108074780, 0.91885558323625 },
{ 1., -1.88903307939452, 0.89487434461664 }
};
const Float_t BButter [9] [3] = {
{ 0.98621192462708, -1.97242384925416, 0.98621192462708 },
{ 0.98500175787242, -1.97000351574484, 0.98500175787242 },
{ 0.97938932735214, -1.95877865470428, 0.97938932735214 },
{ 0.97531843204928, -1.95063686409857, 0.97531843204928 },
{ 0.97316523498161, -1.94633046996323, 0.97316523498161 },
{ 0.96454515552826, -1.92909031105652, 0.96454515552826 },
{ 0.96009142950541, -1.92018285901082, 0.96009142950541 },
{ 0.95856916599601, -1.91713833199203, 0.95856916599601 },
{ 0.94597685600279, -1.89195371200558, 0.94597685600279 }
};
#ifdef WIN32
#pragma warning ( default : 4305 )
#endif
/* When calling this procedure, make sure that ip[-order] and op[-order] point to real data! */
static void
filter ( const Float_t* input, Float_t* output, size_t nSamples, const Float_t* a, const Float_t* b, size_t order )
{
double y;
size_t i;
size_t k;
for ( i = 0; i < nSamples; i++ ) {
y = input[i] * b[0];
for ( k = 1; k <= order; k++ )
y += input[i-k] * b[k] - output[i-k] * a[k];
output[i] = (Float_t)y;
}
}
/* returns a INIT_GAIN_ANALYSIS_OK if successful, INIT_GAIN_ANALYSIS_ERROR if not */
int
ResetSampleFrequency ( long samplefreq ) {
int i;
/* zero out initial values */
for ( i = 0; i < MAX_ORDER; i++ )
linprebuf[i] = lstepbuf[i] = loutbuf[i] = rinprebuf[i] = rstepbuf[i] = routbuf[i] = 0.;
switch ( (int)(samplefreq) ) {
case 48000: freqindex = 0; break;
case 44100: freqindex = 1; break;
case 32000: freqindex = 2; break;
case 24000: freqindex = 3; break;
case 22050: freqindex = 4; break;
case 16000: freqindex = 5; break;
case 12000: freqindex = 6; break;
case 11025: freqindex = 7; break;
case 8000: freqindex = 8; break;
default: return INIT_GAIN_ANALYSIS_ERROR;
}
sampleWindow = (int) ceil (samplefreq * RMS_WINDOW_TIME);
lsum = 0.;
rsum = 0.;
totsamp = 0;
memset ( A, 0, sizeof(A) );
return INIT_GAIN_ANALYSIS_OK;
}
int
InitGainAnalysis ( long samplefreq )
{
if (ResetSampleFrequency(samplefreq) != INIT_GAIN_ANALYSIS_OK) {
return INIT_GAIN_ANALYSIS_ERROR;
}
linpre = linprebuf + MAX_ORDER;
rinpre = rinprebuf + MAX_ORDER;
lstep = lstepbuf + MAX_ORDER;
rstep = rstepbuf + MAX_ORDER;
lout = loutbuf + MAX_ORDER;
rout = routbuf + MAX_ORDER;
memset ( B, 0, sizeof(B) );
return INIT_GAIN_ANALYSIS_OK;
}
/* returns GAIN_ANALYSIS_OK if successful, GAIN_ANALYSIS_ERROR if not */
int
AnalyzeSamples ( const Float_t* left_samples, const Float_t* right_samples, size_t num_samples, int num_channels )
{
const Float_t* curleft;
const Float_t* curright;
long batchsamples;
long cursamples;
long cursamplepos;
int i;
if ( num_samples == 0 )
return GAIN_ANALYSIS_OK;
cursamplepos = 0;
batchsamples = num_samples;
switch ( num_channels) {
case 1: right_samples = left_samples;
case 2: break;
default: return GAIN_ANALYSIS_ERROR;
}
if ( num_samples < MAX_ORDER ) {
memcpy ( linprebuf + MAX_ORDER, left_samples , num_samples * sizeof(Float_t) );
memcpy ( rinprebuf + MAX_ORDER, right_samples, num_samples * sizeof(Float_t) );
}
else {
memcpy ( linprebuf + MAX_ORDER, left_samples, MAX_ORDER * sizeof(Float_t) );
memcpy ( rinprebuf + MAX_ORDER, right_samples, MAX_ORDER * sizeof(Float_t) );
}
while ( batchsamples > 0 ) {
cursamples = batchsamples > sampleWindow-totsamp ? sampleWindow - totsamp : batchsamples;
if ( cursamplepos < MAX_ORDER ) {
curleft = linpre+cursamplepos;
curright = rinpre+cursamplepos;
if (cursamples > MAX_ORDER - cursamplepos )
cursamples = MAX_ORDER - cursamplepos;
}
else {
curleft = left_samples + cursamplepos;
curright = right_samples + cursamplepos;
}
filter ( curleft , lstep + totsamp, cursamples, AYule[freqindex], BYule[freqindex], YULE_ORDER );
filter ( curright, rstep + totsamp, cursamples, AYule[freqindex], BYule[freqindex], YULE_ORDER );
filter ( lstep + totsamp, lout + totsamp, cursamples, AButter[freqindex], BButter[freqindex], BUTTER_ORDER );
filter ( rstep + totsamp, rout + totsamp, cursamples, AButter[freqindex], BButter[freqindex], BUTTER_ORDER );
for ( i = 0; i < cursamples; i++ ) { /* Get the squared values */
lsum += lout [totsamp+i] * lout [totsamp+i];
rsum += rout [totsamp+i] * rout [totsamp+i];
}
batchsamples -= cursamples;
cursamplepos += cursamples;
totsamp += cursamples;
if ( totsamp == sampleWindow ) { /* Get the Root Mean Square (RMS) for this set of samples */
double val = STEPS_per_dB * 10. * log10 ( (lsum+rsum) / totsamp * 0.5 + 1.e-37 );
int ival = (int) val;
if ( ival < 0 ) ival = 0;
if ( ival >= sizeof(A)/sizeof(*A) ) ival = sizeof(A)/sizeof(*A) - 1;
A [ival]++;
lsum = rsum = 0.;
memmove ( loutbuf , loutbuf + totsamp, MAX_ORDER * sizeof(Float_t) );
memmove ( routbuf , routbuf + totsamp, MAX_ORDER * sizeof(Float_t) );
memmove ( lstepbuf, lstepbuf + totsamp, MAX_ORDER * sizeof(Float_t) );
memmove ( rstepbuf, rstepbuf + totsamp, MAX_ORDER * sizeof(Float_t) );
totsamp = 0;
}
if ( totsamp > sampleWindow ) /* somehow I really screwed up: Error in programming! Contact author about totsamp > sampleWindow */
return GAIN_ANALYSIS_ERROR;
}
if ( num_samples < MAX_ORDER ) {
memmove ( linprebuf, linprebuf + num_samples, (MAX_ORDER-num_samples) * sizeof(Float_t) );
memmove ( rinprebuf, rinprebuf + num_samples, (MAX_ORDER-num_samples) * sizeof(Float_t) );
memcpy ( linprebuf + MAX_ORDER - num_samples, left_samples, num_samples * sizeof(Float_t) );
memcpy ( rinprebuf + MAX_ORDER - num_samples, right_samples, num_samples * sizeof(Float_t) );
}
else {
memcpy ( linprebuf, left_samples + num_samples - MAX_ORDER, MAX_ORDER * sizeof(Float_t) );
memcpy ( rinprebuf, right_samples + num_samples - MAX_ORDER, MAX_ORDER * sizeof(Float_t) );
}
return GAIN_ANALYSIS_OK;
}
static Float_t
analyzeResult ( Uint32_t* Array, size_t len )
{
Uint32_t elems;
Int32_t upper;
size_t i;
elems = 0;
for ( i = 0; i < len; i++ )
elems += Array[i];
if ( elems == 0 )
return GAIN_NOT_ENOUGH_SAMPLES;
upper = (Int32_t) ceil (elems * (1. - RMS_PERCENTILE));
for ( i = len; i-- > 0; ) {
if ( (upper -= Array[i]) <= 0 )
break;
}
return (Float_t) ((Float_t)PINK_REF - (Float_t)i / (Float_t)STEPS_per_dB);
}
Float_t
GetTitleGain ( void )
{
Float_t retval;
int i;
retval = analyzeResult ( A, sizeof(A)/sizeof(*A) );
for ( i = 0; i < sizeof(A)/sizeof(*A); i++ ) {
B[i] += A[i];
A[i] = 0;
}
for ( i = 0; i < MAX_ORDER; i++ )
linprebuf[i] = lstepbuf[i] = loutbuf[i] = rinprebuf[i] = rstepbuf[i] = routbuf[i] = 0.f;
totsamp = 0;
lsum = rsum = 0.;
return retval;
}
Float_t
GetAlbumGain ( void )
{
return analyzeResult ( B, sizeof(B)/sizeof(*B) );
}
/* end of gain_analysis.c */
|
