mirror of
https://github.com/RPCS3/soundtouch.git
synced 2024-11-10 04:42:50 +01:00
287 lines
8.2 KiB
C++
287 lines
8.2 KiB
C++
////////////////////////////////////////////////////////////////////////////////
|
||
///
|
||
/// Peak detection routine.
|
||
///
|
||
/// The routine detects highest value on an array of values and calculates the
|
||
/// precise peak location as a mass-center of the 'hump' around the peak value.
|
||
///
|
||
/// Author : Copyright (c) Olli Parviainen
|
||
/// Author e-mail : oparviai 'at' iki.fi
|
||
/// SoundTouch WWW: http://www.surina.net/soundtouch
|
||
///
|
||
////////////////////////////////////////////////////////////////////////////////
|
||
//
|
||
// Last changed : $Date$
|
||
// File revision : $Revision: 4 $
|
||
//
|
||
// $Id$
|
||
//
|
||
////////////////////////////////////////////////////////////////////////////////
|
||
//
|
||
// License :
|
||
//
|
||
// SoundTouch audio processing library
|
||
// Copyright (c) Olli Parviainen
|
||
//
|
||
// 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
|
||
//
|
||
////////////////////////////////////////////////////////////////////////////////
|
||
|
||
#include <math.h>
|
||
#include <assert.h>
|
||
|
||
#include "PeakFinder.h"
|
||
|
||
using namespace soundtouch;
|
||
|
||
#define max(x, y) (((x) > (y)) ? (x) : (y))
|
||
|
||
|
||
PeakFinder::PeakFinder()
|
||
{
|
||
minPos = maxPos = 0;
|
||
}
|
||
|
||
|
||
// Finds real 'top' of a peak hump from neighnourhood of the given 'peakpos'.
|
||
int PeakFinder::findTop(const float *data, int peakpos) const
|
||
{
|
||
int i;
|
||
int start, end;
|
||
float refvalue;
|
||
|
||
refvalue = data[peakpos];
|
||
|
||
// seek within <20>10 points
|
||
start = peakpos - 10;
|
||
if (start < minPos) start = minPos;
|
||
end = peakpos + 10;
|
||
if (end > maxPos) end = maxPos;
|
||
|
||
for (i = start; i <= end; i ++)
|
||
{
|
||
if (data[i] > refvalue)
|
||
{
|
||
peakpos = i;
|
||
refvalue = data[i];
|
||
}
|
||
}
|
||
|
||
// failure if max value is at edges of seek range => it's not peak, it's at slope.
|
||
if ((peakpos == start) || (peakpos == end)) return 0;
|
||
|
||
return peakpos;
|
||
}
|
||
|
||
|
||
// Finds 'ground level' of a peak hump by starting from 'peakpos' and proceeding
|
||
// to direction defined by 'direction' until next 'hump' after minimum value will
|
||
// begin
|
||
int PeakFinder::findGround(const float *data, int peakpos, int direction) const
|
||
{
|
||
int lowpos;
|
||
int pos;
|
||
int climb_count;
|
||
float refvalue;
|
||
float delta;
|
||
|
||
climb_count = 0;
|
||
refvalue = data[peakpos];
|
||
lowpos = peakpos;
|
||
|
||
pos = peakpos;
|
||
|
||
while ((pos > minPos+1) && (pos < maxPos-1))
|
||
{
|
||
int prevpos;
|
||
|
||
prevpos = pos;
|
||
pos += direction;
|
||
|
||
// calculate derivate
|
||
delta = data[pos] - data[prevpos];
|
||
if (delta <= 0)
|
||
{
|
||
// going downhill, ok
|
||
if (climb_count)
|
||
{
|
||
climb_count --; // decrease climb count
|
||
}
|
||
|
||
// check if new minimum found
|
||
if (data[pos] < refvalue)
|
||
{
|
||
// new minimum found
|
||
lowpos = pos;
|
||
refvalue = data[pos];
|
||
}
|
||
}
|
||
else
|
||
{
|
||
// going uphill, increase climbing counter
|
||
climb_count ++;
|
||
if (climb_count > 5) break; // we've been climbing too long => it's next uphill => quit
|
||
}
|
||
}
|
||
return lowpos;
|
||
}
|
||
|
||
|
||
// Find offset where the value crosses the given level, when starting from 'peakpos' and
|
||
// proceeds to direction defined in 'direction'
|
||
int PeakFinder::findCrossingLevel(const float *data, float level, int peakpos, int direction) const
|
||
{
|
||
float peaklevel;
|
||
int pos;
|
||
|
||
peaklevel = data[peakpos];
|
||
assert(peaklevel >= level);
|
||
pos = peakpos;
|
||
while ((pos >= minPos) && (pos < maxPos))
|
||
{
|
||
if (data[pos + direction] < level) return pos; // crossing found
|
||
pos += direction;
|
||
}
|
||
return -1; // not found
|
||
}
|
||
|
||
|
||
// Calculates the center of mass location of 'data' array items between 'firstPos' and 'lastPos'
|
||
double PeakFinder::calcMassCenter(const float *data, int firstPos, int lastPos) const
|
||
{
|
||
int i;
|
||
float sum;
|
||
float wsum;
|
||
|
||
sum = 0;
|
||
wsum = 0;
|
||
for (i = firstPos; i <= lastPos; i ++)
|
||
{
|
||
sum += (float)i * data[i];
|
||
wsum += data[i];
|
||
}
|
||
|
||
if (wsum < 1e-6) return 0;
|
||
return sum / wsum;
|
||
}
|
||
|
||
|
||
|
||
/// get exact center of peak near given position by calculating local mass of center
|
||
double PeakFinder::getPeakCenter(const float *data, int peakpos) const
|
||
{
|
||
float peakLevel; // peak level
|
||
int crosspos1, crosspos2; // position where the peak 'hump' crosses cutting level
|
||
float cutLevel; // cutting value
|
||
float groundLevel; // ground level of the peak
|
||
int gp1, gp2; // bottom positions of the peak 'hump'
|
||
|
||
// find ground positions.
|
||
gp1 = findGround(data, peakpos, -1);
|
||
gp2 = findGround(data, peakpos, 1);
|
||
|
||
peakLevel = data[peakpos];
|
||
|
||
if (gp1 == gp2)
|
||
{
|
||
// avoid rounding errors when all are equal
|
||
assert(gp1 == peakpos);
|
||
cutLevel = groundLevel = peakLevel;
|
||
} else {
|
||
// get average of the ground levels
|
||
groundLevel = 0.5f * (data[gp1] + data[gp2]);
|
||
|
||
// calculate 70%-level of the peak
|
||
cutLevel = 0.70f * peakLevel + 0.30f * groundLevel;
|
||
}
|
||
|
||
// find mid-level crossings
|
||
crosspos1 = findCrossingLevel(data, cutLevel, peakpos, -1);
|
||
crosspos2 = findCrossingLevel(data, cutLevel, peakpos, 1);
|
||
|
||
if ((crosspos1 < 0) || (crosspos2 < 0)) return 0; // no crossing, no peak..
|
||
|
||
// calculate mass center of the peak surroundings
|
||
return calcMassCenter(data, crosspos1, crosspos2);
|
||
}
|
||
|
||
|
||
|
||
double PeakFinder::detectPeak(const float *data, int aminPos, int amaxPos)
|
||
{
|
||
|
||
int i;
|
||
int peakpos; // position of peak level
|
||
double highPeak, peak;
|
||
|
||
this->minPos = aminPos;
|
||
this->maxPos = amaxPos;
|
||
|
||
// find absolute peak
|
||
peakpos = minPos;
|
||
peak = data[minPos];
|
||
for (i = minPos + 1; i < maxPos; i ++)
|
||
{
|
||
if (data[i] > peak)
|
||
{
|
||
peak = data[i];
|
||
peakpos = i;
|
||
}
|
||
}
|
||
|
||
// Calculate exact location of the highest peak mass center
|
||
highPeak = getPeakCenter(data, peakpos);
|
||
peak = highPeak;
|
||
|
||
// Now check if the highest peak were in fact harmonic of the true base beat peak
|
||
// - sometimes the highest peak can be Nth harmonic of the true base peak yet
|
||
// just a slightly higher than the true base
|
||
|
||
for (i = 3; i < 10; i ++)
|
||
{
|
||
double peaktmp, harmonic;
|
||
int i1,i2;
|
||
|
||
harmonic = (double)i * 0.5;
|
||
peakpos = (int)(highPeak / harmonic + 0.5f);
|
||
if (peakpos < minPos) break;
|
||
peakpos = findTop(data, peakpos); // seek true local maximum index
|
||
if (peakpos == 0) continue; // no local max here
|
||
|
||
// calculate mass-center of possible harmonic peak
|
||
peaktmp = getPeakCenter(data, peakpos);
|
||
|
||
// accept harmonic peak if
|
||
// (a) it is found
|
||
// (b) is within <20>4% of the expected harmonic interval
|
||
// (c) has at least half x-corr value of the max. peak
|
||
|
||
double diff = harmonic * peaktmp / highPeak;
|
||
if ((diff < 0.96) || (diff > 1.04)) continue; // peak too afar from expected
|
||
|
||
// now compare to highest detected peak
|
||
i1 = (int)(highPeak + 0.5);
|
||
i2 = (int)(peaktmp + 0.5);
|
||
if (data[i2] >= 0.4*data[i1])
|
||
{
|
||
// The harmonic is at least half as high primary peak,
|
||
// thus use the harmonic peak instead
|
||
peak = peaktmp;
|
||
}
|
||
}
|
||
|
||
return peak;
|
||
}
|