From 8adfb3bd99b4dcff2459756af090a640fd7a4b4a Mon Sep 17 00:00:00 2001 From: yo mama Date: Fri, 19 Jun 2015 16:24:27 -0400 Subject: clone --- .../soundtouch/source/SoundTouch/PeakFinder.cpp | 242 +++++++++++++++++++++ 1 file changed, 242 insertions(+) create mode 100644 pysoundtouch/soundtouch/source/SoundTouch/PeakFinder.cpp (limited to 'pysoundtouch/soundtouch/source/SoundTouch/PeakFinder.cpp') diff --git a/pysoundtouch/soundtouch/source/SoundTouch/PeakFinder.cpp b/pysoundtouch/soundtouch/source/SoundTouch/PeakFinder.cpp new file mode 100644 index 0000000..3b08ad3 --- /dev/null +++ b/pysoundtouch/soundtouch/source/SoundTouch/PeakFinder.cpp @@ -0,0 +1,242 @@ +//////////////////////////////////////////////////////////////////////////////// +/// +/// 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 +#include +#include + +#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, bool loose) 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 (!loose) { + 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, bool loose) +{ + + 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; +} + + -- cgit v1.2.3-70-g09d2