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author | 2010-12-31 16:45:47 +0100 | |
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committer | 2010-12-31 16:45:47 +0100 | |
commit | a1fb9021ec18a2adee2cc036bc371895d9446ed9 (patch) | |
tree | ce4ace998961afd2e7c7cfb4cc92a2ce967ac1c9 /plugins/dsp_soundtouch/soundtouch/source/SoundTouch/PeakFinder.cpp | |
parent | 6c9eae74db370f3c9df94639c9b2b4f80719cc60 (diff) |
added soundtouch plugin
Diffstat (limited to 'plugins/dsp_soundtouch/soundtouch/source/SoundTouch/PeakFinder.cpp')
-rw-r--r-- | plugins/dsp_soundtouch/soundtouch/source/SoundTouch/PeakFinder.cpp | 239 |
1 files changed, 239 insertions, 0 deletions
diff --git a/plugins/dsp_soundtouch/soundtouch/source/SoundTouch/PeakFinder.cpp b/plugins/dsp_soundtouch/soundtouch/source/SoundTouch/PeakFinder.cpp new file mode 100644 index 00000000..03f60bfa --- /dev/null +++ b/plugins/dsp_soundtouch/soundtouch/source/SoundTouch/PeakFinder.cpp @@ -0,0 +1,239 @@ +////////////////////////////////////////////////////////////////////////////////
+///
+/// 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: 2009-02-21 18:00:14 +0200 (Sat, 21 Feb 2009) $
+// File revision : $Revision: 4 $
+//
+// $Id: PeakFinder.cpp 63 2009-02-21 16:00:14Z oparviai $
+//
+////////////////////////////////////////////////////////////////////////////////
+//
+// 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 '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
+{
+ float refvalue;
+ int lowpos;
+ int pos;
+ int climb_count;
+ float delta;
+
+ climb_count = 0;
+ refvalue = data[peakpos];
+ lowpos = peakpos;
+
+ pos = peakpos;
+
+ while ((pos > minPos) && (pos < maxPos))
+ {
+ 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);
+
+ groundLevel = max(data[gp1], data[gp2]);
+ peakLevel = data[peakpos];
+
+ if (groundLevel < 1e-6) return 0; // ground level too small => detection failed
+ if ((peakLevel / groundLevel) < 1.3) return 0; // peak less than 30% of the ground level => no good peak detected
+
+ // 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 = 2; i < 10; i ++)
+ {
+ double peaktmp, tmp;
+ int i1,i2;
+
+ peakpos = (int)(highPeak / (double)i + 0.5f);
+ if (peakpos < minPos) break;
+
+ // calculate mass-center of possible base peak
+ peaktmp = getPeakCenter(data, peakpos);
+
+ // now compare to highest detected peak
+ i1 = (int)(highPeak + 0.5);
+ i2 = (int)(peaktmp + 0.5);
+ tmp = 2 * (data[i2] - data[i1]) / (data[i2] + data[i1]);
+ if (fabs(tmp) < 0.1)
+ {
+ // The highest peak is harmonic of almost as high base peak,
+ // thus use the base peak instead
+ peak = peaktmp;
+ }
+ }
+
+ return peak;
+}
+
+
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