Chris@31: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
Chris@31: 
Chris@31: /*
Chris@31:   Silvet
Chris@31: 
Chris@31:   A Vamp plugin for note transcription.
Chris@31:   Centre for Digital Music, Queen Mary University of London.
Chris@31:     
Chris@31:   This program is free software; you can redistribute it and/or
Chris@31:   modify it under the terms of the GNU General Public License as
Chris@31:   published by the Free Software Foundation; either version 2 of the
Chris@31:   License, or (at your option) any later version.  See the file
Chris@31:   COPYING included with this distribution for more information.
Chris@31: */
Chris@31: 
Chris@31: #include "Silvet.h"
Chris@34: #include "EM.h"
Chris@31: 
Chris@152: #include <cq/CQSpectrogram.h>
Chris@31: 
Chris@152: #include "MedianFilter.h"
Chris@152: #include "constant-q-cpp/src/dsp/Resampler.h"
Chris@31: 
Chris@31: #include <vector>
Chris@31: 
Chris@32: #include <cstdio>
Chris@32: 
Chris@31: using std::vector;
Chris@48: using std::cout;
Chris@31: using std::cerr;
Chris@31: using std::endl;
Chris@40: using Vamp::RealTime;
Chris@31: 
Chris@31: static int processingSampleRate = 44100;
Chris@31: static int processingBPO = 60;
Chris@32: static int processingHeight = 545;
Chris@38: static int processingNotes = 88;
Chris@31: 
Chris@31: Silvet::Silvet(float inputSampleRate) :
Chris@31:     Plugin(inputSampleRate),
Chris@161:     m_instruments(InstrumentPack::listInstrumentPacks()),
Chris@31:     m_resampler(0),
Chris@110:     m_cq(0),
Chris@162:     m_hqMode(true),
Chris@166:     m_fineTuning(false),
Chris@162:     m_instrument(0)
Chris@31: {
Chris@31: }
Chris@31: 
Chris@31: Silvet::~Silvet()
Chris@31: {
Chris@31:     delete m_resampler;
Chris@31:     delete m_cq;
Chris@41:     for (int i = 0; i < (int)m_postFilter.size(); ++i) {
Chris@41:         delete m_postFilter[i];
Chris@41:     }
Chris@31: }
Chris@31: 
Chris@31: string
Chris@31: Silvet::getIdentifier() const
Chris@31: {
Chris@31:     return "silvet";
Chris@31: }
Chris@31: 
Chris@31: string
Chris@31: Silvet::getName() const
Chris@31: {
Chris@31:     return "Silvet Note Transcription";
Chris@31: }
Chris@31: 
Chris@31: string
Chris@31: Silvet::getDescription() const
Chris@31: {
Chris@31:     // Return something helpful here!
Chris@31:     return "";
Chris@31: }
Chris@31: 
Chris@31: string
Chris@31: Silvet::getMaker() const
Chris@31: {
Chris@31:     // Your name here
Chris@31:     return "";
Chris@31: }
Chris@31: 
Chris@31: int
Chris@31: Silvet::getPluginVersion() const
Chris@31: {
Chris@31:     return 1;
Chris@31: }
Chris@31: 
Chris@31: string
Chris@31: Silvet::getCopyright() const
Chris@31: {
Chris@31:     // This function is not ideally named.  It does not necessarily
Chris@31:     // need to say who made the plugin -- getMaker does that -- but it
Chris@31:     // should indicate the terms under which it is distributed.  For
Chris@31:     // example, "Copyright (year). All Rights Reserved", or "GPL"
Chris@31:     return "";
Chris@31: }
Chris@31: 
Chris@31: Silvet::InputDomain
Chris@31: Silvet::getInputDomain() const
Chris@31: {
Chris@31:     return TimeDomain;
Chris@31: }
Chris@31: 
Chris@31: size_t
Chris@31: Silvet::getPreferredBlockSize() const
Chris@31: {
Chris@31:     return 0;
Chris@31: }
Chris@31: 
Chris@31: size_t 
Chris@31: Silvet::getPreferredStepSize() const
Chris@31: {
Chris@31:     return 0;
Chris@31: }
Chris@31: 
Chris@31: size_t
Chris@31: Silvet::getMinChannelCount() const
Chris@31: {
Chris@31:     return 1;
Chris@31: }
Chris@31: 
Chris@31: size_t
Chris@31: Silvet::getMaxChannelCount() const
Chris@31: {
Chris@31:     return 1;
Chris@31: }
Chris@31: 
Chris@31: Silvet::ParameterList
Chris@31: Silvet::getParameterDescriptors() const
Chris@31: {
Chris@31:     ParameterList list;
Chris@110: 
Chris@110:     ParameterDescriptor desc;
Chris@110:     desc.identifier = "mode";
Chris@110:     desc.name = "Processing mode";
Chris@110:     desc.unit = "";
Chris@110:     desc.description = "Determines the tradeoff of processing speed against transcription quality";
Chris@110:     desc.minValue = 0;
Chris@110:     desc.maxValue = 1;
Chris@113:     desc.defaultValue = 1;
Chris@110:     desc.isQuantized = true;
Chris@110:     desc.quantizeStep = 1;
Chris@166:     desc.valueNames.push_back("Draft (faster)"); 
Chris@165:     desc.valueNames.push_back("Intensive (higher quality)");
Chris@161:     list.push_back(desc);
Chris@161: 
Chris@161:     desc.identifier = "soloinstrument";
Chris@165:     desc.name = "Solo instrument";
Chris@161:     desc.unit = "";
Chris@162:     desc.description = "The instrument known to be present in the recording, if there is only one";
Chris@161:     desc.minValue = 0;
Chris@162:     desc.maxValue = m_instruments.size()-1;
Chris@162:     desc.defaultValue = 0;
Chris@161:     desc.isQuantized = true;
Chris@161:     desc.quantizeStep = 1;
Chris@161:     desc.valueNames.clear();
Chris@162:     for (int i = 0; i < int(m_instruments.size()); ++i) {
Chris@162:         desc.valueNames.push_back(m_instruments[i].name);
Chris@162:     }
Chris@166:     list.push_back(desc);
Chris@161: 
Chris@166:     desc.identifier = "finetune";
Chris@166:     desc.name = "Return fine pitch estimates";
Chris@166:     desc.unit = "";
Chris@166:     desc.description = "Return pitch estimates at finer than semitone resolution (works only in Intensive mode)";
Chris@166:     desc.minValue = 0;
Chris@166:     desc.maxValue = 1;
Chris@166:     desc.defaultValue = 0;
Chris@166:     desc.isQuantized = true;
Chris@166:     desc.quantizeStep = 1;
Chris@166:     desc.valueNames.clear();
Chris@110:     list.push_back(desc);
Chris@110: 
Chris@31:     return list;
Chris@31: }
Chris@31: 
Chris@31: float
Chris@31: Silvet::getParameter(string identifier) const
Chris@31: {
Chris@110:     if (identifier == "mode") {
Chris@110:         return m_hqMode ? 1.f : 0.f;
Chris@166:     } else if (identifier == "finetune") {
Chris@166:         return m_fineTuning ? 1.f : 0.f;
Chris@162:     } else if (identifier == "soloinstrument") {
Chris@162:         return m_instrument;
Chris@110:     }
Chris@31:     return 0;
Chris@31: }
Chris@31: 
Chris@31: void
Chris@31: Silvet::setParameter(string identifier, float value) 
Chris@31: {
Chris@110:     if (identifier == "mode") {
Chris@110:         m_hqMode = (value > 0.5);
Chris@166:     } else if (identifier == "finetune") {
Chris@166:         m_fineTuning = (value > 0.5);
Chris@162:     } else if (identifier == "soloinstrument") {
Chris@162:         m_instrument = lrintf(value);
Chris@110:     }
Chris@31: }
Chris@31: 
Chris@31: Silvet::ProgramList
Chris@31: Silvet::getPrograms() const
Chris@31: {
Chris@31:     ProgramList list;
Chris@31:     return list;
Chris@31: }
Chris@31: 
Chris@31: string
Chris@31: Silvet::getCurrentProgram() const
Chris@31: {
Chris@31:     return ""; 
Chris@31: }
Chris@31: 
Chris@31: void
Chris@31: Silvet::selectProgram(string name)
Chris@31: {
Chris@31: }
Chris@31: 
Chris@31: Silvet::OutputList
Chris@31: Silvet::getOutputDescriptors() const
Chris@31: {
Chris@31:     OutputList list;
Chris@31: 
Chris@31:     OutputDescriptor d;
Chris@51:     d.identifier = "notes";
Chris@51:     d.name = "Note transcription";
Chris@162:     d.description = "Overall note transcription across selected instruments";
Chris@41:     d.unit = "Hz";
Chris@31:     d.hasFixedBinCount = true;
Chris@31:     d.binCount = 2;
Chris@41:     d.binNames.push_back("Frequency");
Chris@31:     d.binNames.push_back("Velocity");
Chris@31:     d.hasKnownExtents = false;
Chris@31:     d.isQuantized = false;
Chris@31:     d.sampleType = OutputDescriptor::VariableSampleRate;
Chris@51:     d.sampleRate = m_inputSampleRate / (m_cq ? m_cq->getColumnHop() : 62);
Chris@31:     d.hasDuration = true;
Chris@32:     m_notesOutputNo = list.size();
Chris@32:     list.push_back(d);
Chris@32: 
Chris@31:     return list;
Chris@31: }
Chris@31: 
Chris@38: std::string
Chris@38: Silvet::noteName(int i) const
Chris@38: {
Chris@38:     static const char *names[] = {
Chris@38:         "A", "A#", "B", "C", "C#", "D", "D#", "E", "F", "F#", "G", "G#"
Chris@38:     };
Chris@38: 
Chris@38:     const char *n = names[i % 12];
Chris@38: 
Chris@38:     int oct = (i + 9) / 12; 
Chris@38:     
Chris@38:     char buf[20];
Chris@38:     sprintf(buf, "%s%d", n, oct);
Chris@38: 
Chris@38:     return buf;
Chris@38: }
Chris@38: 
Chris@41: float
Chris@168: Silvet::noteFrequency(int note, int shift, int shiftCount) const
Chris@41: {
Chris@168:     float fineNote = float(note) + float(shift) / float(shiftCount);
Chris@167:     return float(27.5 * pow(2.0, fineNote / 12.0));
Chris@41: }
Chris@41: 
Chris@31: bool
Chris@31: Silvet::initialise(size_t channels, size_t stepSize, size_t blockSize)
Chris@31: {
Chris@31:     if (channels < getMinChannelCount() ||
Chris@31: 	channels > getMaxChannelCount()) return false;
Chris@31: 
Chris@31:     if (stepSize != blockSize) {
Chris@31: 	cerr << "Silvet::initialise: Step size must be the same as block size ("
Chris@31: 	     << stepSize << " != " << blockSize << ")" << endl;
Chris@31: 	return false;
Chris@31:     }
Chris@31: 
Chris@31:     m_blockSize = blockSize;
Chris@31: 
Chris@31:     reset();
Chris@31: 
Chris@31:     return true;
Chris@31: }
Chris@31: 
Chris@31: void
Chris@31: Silvet::reset()
Chris@31: {
Chris@31:     delete m_resampler;
Chris@31:     delete m_cq;
Chris@31: 
Chris@31:     if (m_inputSampleRate != processingSampleRate) {
Chris@31: 	m_resampler = new Resampler(m_inputSampleRate, processingSampleRate);
Chris@31:     } else {
Chris@31: 	m_resampler = 0;
Chris@31:     }
Chris@31: 
Chris@154:     CQParameters params(processingSampleRate,
Chris@154:                         27.5, 
Chris@154:                         processingSampleRate / 3,
Chris@154:                         processingBPO);
Chris@154: 
Chris@155:     params.q = 0.95; // MIREX code uses 0.8, but it seems 0.9 or lower
Chris@155:                      // drops the FFT size to 512 from 1024 and alters
Chris@155:                      // some other processing parameters, making
Chris@155:                      // everything much, much slower. Could be a flaw
Chris@155:                      // in the CQ parameter calculations, must check
Chris@154:     params.atomHopFactor = 0.3;
Chris@154:     params.threshold = 0.0005;
Chris@155:     params.window = CQParameters::Hann; //!!! todo: test whether it makes any difference
Chris@154: 
Chris@154:     m_cq = new CQSpectrogram(params, CQSpectrogram::InterpolateLinear);
Chris@31: 
Chris@165:     m_colsPerSec = m_hqMode ? 50 : 25;
Chris@165: 
Chris@41:     for (int i = 0; i < (int)m_postFilter.size(); ++i) {
Chris@41:         delete m_postFilter[i];
Chris@41:     }
Chris@41:     m_postFilter.clear();
Chris@41:     for (int i = 0; i < processingNotes; ++i) {
Chris@41:         m_postFilter.push_back(new MedianFilter<double>(3));
Chris@41:     }
Chris@41:     m_pianoRoll.clear();
Chris@32:     m_columnCount = 0;
Chris@40:     m_startTime = RealTime::zeroTime;
Chris@31: }
Chris@31: 
Chris@31: Silvet::FeatureSet
Chris@31: Silvet::process(const float *const *inputBuffers, Vamp::RealTime timestamp)
Chris@31: {
Chris@40:     if (m_columnCount == 0) {
Chris@40:         m_startTime = timestamp;
Chris@40:     }
Chris@40:     
Chris@31:     vector<double> data;
Chris@40:     for (int i = 0; i < m_blockSize; ++i) {
Chris@40:         data.push_back(inputBuffers[0][i]);
Chris@40:     }
Chris@31: 
Chris@31:     if (m_resampler) {
Chris@31: 	data = m_resampler->process(data.data(), data.size());
Chris@31:     }
Chris@31: 
Chris@32:     Grid cqout = m_cq->process(data);
Chris@51:     FeatureSet fs = transcribe(cqout);
Chris@51:     return fs;
Chris@34: }
Chris@34: 
Chris@34: Silvet::FeatureSet
Chris@34: Silvet::getRemainingFeatures()
Chris@34: {
Chris@145:     Grid cqout = m_cq->getRemainingOutput();
Chris@51:     FeatureSet fs = transcribe(cqout);
Chris@51:     return fs;
Chris@34: }
Chris@34: 
Chris@34: Silvet::FeatureSet
Chris@34: Silvet::transcribe(const Grid &cqout)
Chris@34: {
Chris@32:     Grid filtered = preProcess(cqout);
Chris@31: 
Chris@32:     FeatureSet fs;
Chris@32: 
Chris@104:     if (filtered.empty()) return fs;
Chris@104: 
Chris@34:     int width = filtered.size();
Chris@34: 
Chris@164:     int iterations = m_hqMode ? 20 : 10;
Chris@34: 
Chris@166:     vector<EM *> em(width, (EM *)0);
Chris@166:     vector<double> sums(width, 0.0);
Chris@37: 
Chris@123: #pragma omp parallel for
Chris@123:     for (int i = 0; i < width; ++i) {
Chris@104: 
Chris@123:         for (int j = 0; j < processingHeight; ++j) {
Chris@166:             sums[i] += filtered.at(i).at(j);
Chris@37:         }
Chris@37: 
Chris@166:         if (sums[i] < 1e-5) continue;
Chris@37: 
Chris@166:         em[i] = new EM(&m_instruments[m_instrument], m_hqMode);
Chris@104: 
Chris@123:         for (int j = 0; j < iterations; ++j) {
Chris@166:             em[i]->iterate(filtered.at(i).data());
Chris@123:         }
Chris@123:     }
Chris@167: 
Chris@167:     int shiftCount = 1;
Chris@168: 
Chris@167:     if (m_hqMode && m_fineTuning) {
Chris@167:         shiftCount = m_instruments[m_instrument].templateMaxShift * 2 + 1;
Chris@167:     }
Chris@166:         
Chris@166:     for (int i = 0; i < width; ++i) {
Chris@37: 
Chris@166:         if (!em[i]) {
Chris@168:             m_pianoRoll.push_back(map<int, double>());
Chris@168:             if (shiftCount > 1) {
Chris@168:                 m_pianoRollShifts.push_back(map<int, int>());
Chris@168:             }
Chris@166:             continue;
Chris@166:         }
Chris@166: 
Chris@168:         postProcess(em[i]->getPitchDistribution(),
Chris@168:                     em[i]->getShifts(),
Chris@168:                     shiftCount,
Chris@168:                     sums[i]);
Chris@123:         
Chris@166:         delete em[i];
Chris@166:         
Chris@168:         FeatureList noteFeatures = noteTrack(shiftCount);
Chris@38: 
Chris@123:         for (FeatureList::const_iterator fi = noteFeatures.begin();
Chris@123:              fi != noteFeatures.end(); ++fi) {
Chris@123:             fs[m_notesOutputNo].push_back(*fi);
Chris@40:         }
Chris@34:     }
Chris@34: 
Chris@32:     return fs;
Chris@31: }
Chris@31: 
Chris@32: Silvet::Grid
Chris@32: Silvet::preProcess(const Grid &in)
Chris@32: {
Chris@32:     int width = in.size();
Chris@32: 
Chris@165:     int spacing = processingSampleRate / m_colsPerSec;
Chris@32: 
Chris@165:     // need to be careful that col spacing is an integer number of samples!
Chris@165:     assert(spacing * m_colsPerSec == processingSampleRate);
Chris@32: 
Chris@32:     Grid out;
Chris@32: 
Chris@58:     // We count the CQ latency in terms of processing hops, but
Chris@58:     // actually it probably isn't an exact number of hops so this
Chris@58:     // isn't quite accurate. But the small constant offset is
Chris@165:     // practically irrelevant compared to the jitter from the frame
Chris@165:     // size we reduce to in a moment
Chris@33:     int latentColumns = m_cq->getLatency() / m_cq->getColumnHop();
Chris@33: 
Chris@32:     for (int i = 0; i < width; ++i) {
Chris@32: 
Chris@33:         if (m_columnCount < latentColumns) {
Chris@33:             ++m_columnCount;
Chris@33:             continue;
Chris@33:         }
Chris@33: 
Chris@32:         int prevSampleNo = (m_columnCount - 1) * m_cq->getColumnHop();
Chris@32:         int sampleNo = m_columnCount * m_cq->getColumnHop();
Chris@32: 
Chris@32:         bool select = (sampleNo / spacing != prevSampleNo / spacing);
Chris@32: 
Chris@32:         if (select) {
Chris@32:             vector<double> inCol = in[i];
Chris@32:             vector<double> outCol(processingHeight);
Chris@32: 
Chris@32:             // we reverse the column as we go (the CQ output is
Chris@32:             // "upside-down", with high frequencies at the start of
Chris@32:             // each column, and we want it the other way around) and
Chris@32:             // then ignore the first 55 (lowest-frequency) bins,
Chris@32:             // giving us 545 bins instead of 600
Chris@32: 
Chris@32:             for (int j = 0; j < processingHeight; ++j) {
Chris@46:                 int ix = inCol.size() - j - 55;
Chris@46:                 outCol[j] = inCol[ix];
Chris@46:             }
Chris@32: 
Chris@46:             vector<double> noiseLevel1 = 
Chris@46:                 MedianFilter<double>::filter(40, outCol);
Chris@46:             for (int j = 0; j < processingHeight; ++j) {
Chris@46:                 noiseLevel1[j] = std::min(outCol[j], noiseLevel1[j]);
Chris@46:             }
Chris@32: 
Chris@46:             vector<double> noiseLevel2 = 
Chris@46:                 MedianFilter<double>::filter(40, noiseLevel1);
Chris@46:             for (int j = 0; j < processingHeight; ++j) {
Chris@46:                 outCol[j] = std::max(outCol[j] - noiseLevel2[j], 0.0);
Chris@32:             }
Chris@32: 
Chris@165:             out.push_back(outCol);
Chris@32:         }
Chris@32: 
Chris@32:         ++m_columnCount;
Chris@32:     }
Chris@32: 
Chris@32:     return out;
Chris@32: }
Chris@32:     
Chris@168: void
Chris@166: Silvet::postProcess(const float *pitches,
Chris@166:                     const float *const *shifts,
Chris@166:                     int shiftCount,
Chris@166:                     double gain)
Chris@166: {
Chris@41:     vector<double> filtered;
Chris@41: 
Chris@41:     for (int j = 0; j < processingNotes; ++j) {
Chris@166:         m_postFilter[j]->push(pitches[j] * gain);
Chris@41:         filtered.push_back(m_postFilter[j]->get());
Chris@41:     }
Chris@41: 
Chris@41:     // Threshold for level and reduce number of candidate pitches
Chris@41: 
Chris@41:     int polyphony = 5;
Chris@150: 
Chris@150:     //!!! make this a parameter (was 4.8, try adjusting, compare levels against matlab code)
Chris@150:     double threshold = 6;
Chris@154: //    double threshold = 4.8;
Chris@41: 
Chris@41:     typedef std::multimap<double, int> ValueIndexMap;
Chris@41: 
Chris@41:     ValueIndexMap strengths;
Chris@166: 
Chris@41:     for (int j = 0; j < processingNotes; ++j) {
Chris@166: 
Chris@166:         double strength = filtered[j];
Chris@166:         if (strength < threshold) continue;
Chris@166: 
Chris@168:         strengths.insert(ValueIndexMap::value_type(strength, j));
Chris@168:     }
Chris@166: 
Chris@168:     ValueIndexMap::const_iterator si = strengths.end();
Chris@167: 
Chris@168:     map<int, double> active;
Chris@168:     map<int, int> activeShifts;
Chris@168: 
Chris@168:     while (int(active.size()) < polyphony && si != strengths.begin()) {
Chris@168: 
Chris@168:         --si;
Chris@168: 
Chris@168:         double strength = si->first;
Chris@168:         int j = si->second;
Chris@168: 
Chris@168:         active[j] = strength;
Chris@168: 
Chris@168:         if (shiftCount > 1) {
Chris@168: 
Chris@168:             // find preferred shift f for note j
Chris@168:             int bestShift = 0;
Chris@168: 
Chris@167:             float bestShiftValue = 0.f;
Chris@167:             for (int f = 0; f < shiftCount; ++f) {
Chris@167:                 if (f == 0 || shifts[f][j] > bestShiftValue) {
Chris@167:                     bestShiftValue = shifts[f][j];
Chris@168:                     bestShift = f - int(shiftCount / 2);
Chris@167:                 }
Chris@167:             }
Chris@167:             //!!! I think our shift array per note is actually upside down, check this
Chris@168: 
Chris@168:             activeShifts[j] = bestShift;
Chris@167:         }
Chris@41:     }
Chris@41: 
Chris@168:     m_pianoRoll.push_back(active);
Chris@168:     if (shiftCount > 1) {
Chris@168:         m_pianoRollShifts.push_back(activeShifts);
Chris@41:     }
Chris@166: }
Chris@166: 
Chris@166: Vamp::Plugin::FeatureList
Chris@168: Silvet::noteTrack(int shiftCount)
Chris@166: {        
Chris@41:     // Minimum duration pruning, and conversion to notes. We can only
Chris@41:     // report notes that have just ended (i.e. that are absent in the
Chris@168:     // latest active set but present in the prior set in the piano
Chris@41:     // roll) -- any notes that ended earlier will have been reported
Chris@41:     // already, and if they haven't ended, we don't know their
Chris@41:     // duration.
Chris@41: 
Chris@166:     int postFilterLatency = int(m_postFilter[0]->getSize() / 2);
Chris@166: 
Chris@168:     int width = m_pianoRoll.size() - 1;
Chris@168: 
Chris@168:     const map<int, double> &active = m_pianoRoll[width];
Chris@41: 
Chris@165:     double columnDuration = 1.0 / m_colsPerSec;
Chris@165: 
Chris@165:     // only keep notes >= 100ms or thereabouts
Chris@165:     int durationThreshold = floor(0.1 / columnDuration); // columns
Chris@165:     if (durationThreshold < 1) durationThreshold = 1;
Chris@41: 
Chris@41:     FeatureList noteFeatures;
Chris@41: 
Chris@41:     if (width < durationThreshold + 1) {
Chris@41:         return noteFeatures;
Chris@41:     }
Chris@41:     
Chris@150:     //!!! try: repeated note detection? (look for change in first derivative of the pitch matrix)
Chris@150: 
Chris@55:     for (map<int, double>::const_iterator ni = m_pianoRoll[width-1].begin();
Chris@41:          ni != m_pianoRoll[width-1].end(); ++ni) {
Chris@41: 
Chris@55:         int note = ni->first;
Chris@41:         
Chris@41:         if (active.find(note) != active.end()) {
Chris@41:             // the note is still playing
Chris@41:             continue;
Chris@41:         }
Chris@41: 
Chris@41:         // the note was playing but just ended
Chris@41:         int end = width;
Chris@41:         int start = end-1;
Chris@41: 
Chris@57:         double maxStrength = 0.0;
Chris@55: 
Chris@41:         while (m_pianoRoll[start].find(note) != m_pianoRoll[start].end()) {
Chris@57:             double strength = m_pianoRoll[start][note];
Chris@57:             if (strength > maxStrength) {
Chris@57:                 maxStrength = strength;
Chris@57:             }
Chris@41:             --start;
Chris@41:         }
Chris@41:         ++start;
Chris@41: 
Chris@41:         int duration = width - start;
Chris@62: //        cerr << "duration " << duration << " for just-ended note " << note << endl;
Chris@41:         if (duration < durationThreshold) {
Chris@41:             // spurious
Chris@41:             continue;
Chris@41:         }
Chris@41: 
Chris@57:         int velocity = maxStrength * 2;
Chris@55:         if (velocity > 127) velocity = 127;
Chris@55: 
Chris@152: //        cerr << "Found a genuine note, starting at " << columnDuration * start << " with duration " << columnDuration * duration << endl;
Chris@62: 
Chris@41:         Feature nf;
Chris@41:         nf.hasTimestamp = true;
Chris@69:         nf.timestamp = RealTime::fromSeconds
Chris@150:             (columnDuration * (start - postFilterLatency) + 0.02);
Chris@41:         nf.hasDuration = true;
Chris@69:         nf.duration = RealTime::fromSeconds
Chris@69:             (columnDuration * duration);
Chris@167:         nf.values.push_back(noteFrequency(note, shiftCount));
Chris@55:         nf.values.push_back(velocity);
Chris@41:         nf.label = noteName(note);
Chris@41:         noteFeatures.push_back(nf);
Chris@41:     }
Chris@41: 
Chris@62: //    cerr << "returning " << noteFeatures.size() << " complete note(s) " << endl;
Chris@41: 
Chris@41:     return noteFeatures;
Chris@41: }
Chris@41: