Chris@47: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
Chris@47: 
Chris@47: /*
Chris@47:   Centre for Digital Music, Queen Mary University of London.
Chris@47:     
Chris@47:   This program is free software; you can redistribute it and/or
Chris@47:   modify it under the terms of the GNU General Public License as
Chris@47:   published by the Free Software Foundation; either version 2 of the
Chris@47:   License, or (at your option) any later version.  See the file
Chris@47:   COPYING included with this distribution for more information.
Chris@47: */
Chris@47: 
Chris@55: #include "TuningDifference.h"
Chris@47: 
Chris@47: #include <iostream>
Chris@47: 
Chris@47: #include <cmath>
Chris@47: #include <cstdio>
Chris@47: #include <climits>
Chris@47: 
Chris@47: #include <algorithm>
Chris@47: #include <numeric>
Chris@47: 
Chris@47: using namespace std;
Chris@47: 
Chris@47: static double pitchToFrequency(int pitch,
Chris@47: 			       double centsOffset = 0.,
Chris@47: 			       double concertA = 440.)
Chris@47: {
Chris@47:     double p = double(pitch) + (centsOffset / 100.);
Chris@47:     return concertA * pow(2.0, (p - 69.0) / 12.0); 
Chris@47: }
Chris@47: 
Chris@47: static double frequencyForCentsAbove440(double cents)
Chris@47: {
Chris@47:     return pitchToFrequency(69, cents, 440.);
Chris@47: }
Chris@47: 
Chris@47: static float defaultMaxDuration = 0.f;
Chris@50: static int defaultMaxSemis = 5;
Chris@47: static bool defaultFineTuning = true;
Chris@47: 
Chris@55: TuningDifference::TuningDifference(float inputSampleRate) :
Chris@47:     Plugin(inputSampleRate),
Chris@47:     m_channelCount(0),
Chris@47:     m_bpo(120),
Chris@47:     m_blockSize(0),
Chris@47:     m_frameCount(0),
Chris@47:     m_maxDuration(defaultMaxDuration),
Chris@47:     m_maxSemis(defaultMaxSemis),
Chris@47:     m_fineTuning(defaultFineTuning)
Chris@47: {
Chris@47: }
Chris@47: 
Chris@55: TuningDifference::~TuningDifference()
Chris@47: {
Chris@47: }
Chris@47: 
Chris@47: string
Chris@55: TuningDifference::getIdentifier() const
Chris@47: {
Chris@55:     return "tuning-difference";
Chris@47: }
Chris@47: 
Chris@47: string
Chris@55: TuningDifference::getName() const
Chris@47: {
Chris@55:     return "Tuning Difference";
Chris@47: }
Chris@47: 
Chris@47: string
Chris@55: TuningDifference::getDescription() const
Chris@47: {
Chris@47:     return "Estimate the tuning frequencies of a set of recordings at once, by comparing them to a reference recording of the same music whose tuning frequency is known";
Chris@47: }
Chris@47: 
Chris@47: string
Chris@55: TuningDifference::getMaker() const
Chris@47: {
Chris@47:     return "Chris Cannam";
Chris@47: }
Chris@47: 
Chris@47: int
Chris@55: TuningDifference::getPluginVersion() const
Chris@47: {
Chris@47:     // Increment this each time you release a version that behaves
Chris@47:     // differently from the previous one
Chris@47:     return 3;
Chris@47: }
Chris@47: 
Chris@47: string
Chris@55: TuningDifference::getCopyright() const
Chris@47: {
Chris@47:     // This function is not ideally named.  It does not necessarily
Chris@47:     // need to say who made the plugin -- getMaker does that -- but it
Chris@47:     // should indicate the terms under which it is distributed.  For
Chris@47:     // example, "Copyright (year). All Rights Reserved", or "GPL"
Chris@47:     return "GPL";
Chris@47: }
Chris@47: 
Chris@55: TuningDifference::InputDomain
Chris@55: TuningDifference::getInputDomain() const
Chris@47: {
Chris@47:     return TimeDomain;
Chris@47: }
Chris@47: 
Chris@47: size_t
Chris@55: TuningDifference::getPreferredBlockSize() const
Chris@47: {
Chris@47:     return 0;
Chris@47: }
Chris@47: 
Chris@47: size_t 
Chris@55: TuningDifference::getPreferredStepSize() const
Chris@47: {
Chris@47:     return 0;
Chris@47: }
Chris@47: 
Chris@47: size_t
Chris@55: TuningDifference::getMinChannelCount() const
Chris@47: {
Chris@47:     return 2;
Chris@47: }
Chris@47: 
Chris@47: size_t
Chris@55: TuningDifference::getMaxChannelCount() const
Chris@47: {
Chris@52:     return 1000;
Chris@47: }
Chris@47: 
Chris@55: TuningDifference::ParameterList
Chris@55: TuningDifference::getParameterDescriptors() const
Chris@47: {
Chris@47:     ParameterList list;
Chris@47: 
Chris@47:     ParameterDescriptor desc;
Chris@47: 
Chris@47:     desc.identifier = "maxduration";
Chris@47:     desc.name = "Maximum duration to analyse";
Chris@47:     desc.description = "The maximum duration (in seconds) to consider from either input file, always taken from the start of the input. Zero means there is no limit.";
Chris@47:     desc.minValue = 0;
Chris@47:     desc.maxValue = 3600;
Chris@47:     desc.defaultValue = defaultMaxDuration;
Chris@47:     desc.isQuantized = false;
Chris@47:     desc.unit = "s";
Chris@47:     list.push_back(desc);
Chris@47:     
Chris@47:     desc.identifier = "maxrange";
Chris@47:     desc.name = "Maximum range in semitones";
Chris@47:     desc.description = "The maximum difference in semitones that will be searched.";
Chris@47:     desc.minValue = 1;
Chris@47:     desc.maxValue = 11;
Chris@47:     desc.defaultValue = defaultMaxSemis;
Chris@47:     desc.isQuantized = true;
Chris@47:     desc.quantizeStep = 1;
Chris@47:     desc.unit = "semitones";
Chris@47:     list.push_back(desc);
Chris@47:     
Chris@47:     desc.identifier = "finetuning";
Chris@47:     desc.name = "Fine tuning";
Chris@47:     desc.description = "Use a fine tuning stage to increase nominal resolution from 10 cents to 1 cent.";
Chris@47:     desc.minValue = 0;
Chris@47:     desc.maxValue = 1;
Chris@47:     desc.defaultValue = (defaultFineTuning ? 1.f : 0.f);
Chris@47:     desc.isQuantized = true;
Chris@47:     desc.quantizeStep = 1;
Chris@47:     desc.unit = "";
Chris@47:     list.push_back(desc);
Chris@47: 
Chris@47:     return list;
Chris@47: }
Chris@47: 
Chris@47: float
Chris@55: TuningDifference::getParameter(string id) const
Chris@47: {
Chris@47:     if (id == "maxduration") {
Chris@47:         return m_maxDuration;
Chris@47:     } else if (id == "maxrange") {
Chris@47:         return float(m_maxSemis);
Chris@47:     } else if (id == "finetuning") {
Chris@47:         return m_fineTuning ? 1.f : 0.f;
Chris@47:     }
Chris@47:     return 0;
Chris@47: }
Chris@47: 
Chris@47: void
Chris@55: TuningDifference::setParameter(string id, float value) 
Chris@47: {
Chris@47:     if (id == "maxduration") {
Chris@47:         m_maxDuration = value;
Chris@47:     } else if (id == "maxrange") {
Chris@47:         m_maxSemis = int(roundf(value));
Chris@47:     } else if (id == "finetuning") {
Chris@47:         m_fineTuning = (value > 0.5f);
Chris@47:     }
Chris@47: }
Chris@47: 
Chris@55: TuningDifference::ProgramList
Chris@55: TuningDifference::getPrograms() const
Chris@47: {
Chris@47:     ProgramList list;
Chris@47:     return list;
Chris@47: }
Chris@47: 
Chris@47: string
Chris@55: TuningDifference::getCurrentProgram() const
Chris@47: {
Chris@47:     return ""; // no programs
Chris@47: }
Chris@47: 
Chris@47: void
Chris@55: TuningDifference::selectProgram(string)
Chris@47: {
Chris@47: }
Chris@47: 
Chris@55: TuningDifference::OutputList
Chris@55: TuningDifference::getOutputDescriptors() const
Chris@47: {
Chris@47:     OutputList list;
Chris@47: 
Chris@47:     OutputDescriptor d;
Chris@47:     d.identifier = "cents";
Chris@47:     d.name = "Tuning Differences";
Chris@47:     d.description = "A single feature vector containing a value for each input channel after the first (reference) channel, containing the difference in averaged frequency profile between that channel and the reference channel, in cents. A positive value means the corresponding channel is higher than the reference.";
Chris@47:     d.unit = "cents";
Chris@54:     d.hasFixedBinCount = true;
Chris@47:     if (m_channelCount > 1) {
Chris@47:         d.binCount = m_channelCount - 1;
Chris@47:     } else {
Chris@54:         d.binCount = 1;
Chris@47:     }
Chris@47:     d.hasKnownExtents = false;
Chris@47:     d.isQuantized = false;
Chris@47:     d.sampleType = OutputDescriptor::VariableSampleRate;
Chris@47:     d.hasDuration = false;
Chris@47:     m_outputs[d.identifier] = int(list.size());
Chris@47:     list.push_back(d);
Chris@47: 
Chris@47:     d.identifier = "tuningfreq";
Chris@47:     d.name = "Relative Tuning Frequencies";
Chris@47:     d.description = "A single feature vector containing a value for each input channel after the first (reference) channel, containing the tuning frequency of that channel, if the reference channel is assumed to contain the same music as it at a tuning frequency of A=440Hz.";
Chris@47:     d.unit = "hz";
Chris@54:     d.hasFixedBinCount = true;
Chris@47:     if (m_channelCount > 1) {
Chris@47:         d.binCount = m_channelCount - 1;
Chris@47:     } else {
Chris@54:         d.binCount = 1;
Chris@47:     }
Chris@47:     d.hasKnownExtents = false;
Chris@47:     d.isQuantized = false;
Chris@47:     d.sampleType = OutputDescriptor::VariableSampleRate;
Chris@47:     d.hasDuration = false;
Chris@47:     m_outputs[d.identifier] = int(list.size());
Chris@47:     list.push_back(d);
Chris@47: 
Chris@47:     d.identifier = "reffeature";
Chris@47:     d.name = "Reference Feature";
Chris@47:     d.description = "Chroma feature from reference channel.";
Chris@47:     d.unit = "";
Chris@47:     d.hasFixedBinCount = true;
Chris@47:     d.binCount = m_bpo;
Chris@47:     d.hasKnownExtents = false;
Chris@47:     d.isQuantized = false;
Chris@47:     d.sampleType = OutputDescriptor::FixedSampleRate;
Chris@47:     d.sampleRate = 1;
Chris@47:     d.hasDuration = false;
Chris@47:     m_outputs[d.identifier] = int(list.size());
Chris@47:     list.push_back(d);
Chris@47: 
Chris@47:     d.identifier = "otherfeature";
Chris@47:     d.name = "Other Features";
Chris@47:     d.description = "Series of chroma feature vectors from the non-reference audio channels, before rotation.";
Chris@47:     d.unit = "";
Chris@47:     d.hasFixedBinCount = true;
Chris@47:     d.binCount = m_bpo;
Chris@47:     d.hasKnownExtents = false;
Chris@47:     d.isQuantized = false;
Chris@47:     d.sampleType = OutputDescriptor::FixedSampleRate;
Chris@47:     d.sampleRate = 1;
Chris@47:     d.hasDuration = false;
Chris@47:     m_outputs[d.identifier] = int(list.size());
Chris@47:     list.push_back(d);
Chris@47: 
Chris@47:     d.identifier = "rotfeature";
Chris@47:     d.name = "Other Features at Rotated Frequency";
Chris@48:     d.description = "Series of chroma feature vectors from the non-reference audio channels, calculated with the tuning frequency obtained from rotation matching. Note that this does not take into account any fine tuning, only the basic rotation match.";
Chris@47:     d.unit = "";
Chris@47:     d.hasFixedBinCount = true;
Chris@47:     d.binCount = m_bpo;
Chris@47:     d.hasKnownExtents = false;
Chris@47:     d.isQuantized = false;
Chris@47:     d.sampleType = OutputDescriptor::FixedSampleRate;
Chris@47:     d.sampleRate = 1;
Chris@47:     d.hasDuration = false;
Chris@47:     m_outputs[d.identifier] = int(list.size());
Chris@47:     list.push_back(d);
Chris@47: 
Chris@47:     return list;
Chris@47: }
Chris@47: 
Chris@47: bool
Chris@55: TuningDifference::initialise(size_t channels, size_t stepSize, size_t blockSize)
Chris@47: {
Chris@47:     if (channels < getMinChannelCount()) return false;
Chris@47:     if (stepSize != blockSize) return false;
Chris@47:     if (m_blockSize > INT_MAX) return false;
Chris@47: 
Chris@50:     m_channelCount = int(channels);
Chris@47:     m_blockSize = int(blockSize);
Chris@47: 
Chris@47:     reset();
Chris@47:     
Chris@47:     return true;
Chris@47: }
Chris@47: 
Chris@47: void
Chris@55: TuningDifference::reset()
Chris@47: {
Chris@50:     Chromagram::Parameters params(paramsForTuningFrequency(440.));
Chris@50:     m_reference.clear();
Chris@50:     m_refChroma.reset(new Chromagram(params));
Chris@50:     m_refTotals = TFeature(m_bpo, 0.0);
Chris@50:     m_refFeatures.clear();
Chris@50:     m_otherChroma.clear();
Chris@50:     for (int i = 1; i < m_channelCount; ++i) {
Chris@50:         m_otherChroma.push_back(std::make_shared<Chromagram>(params));
Chris@47:     }
Chris@50:     m_otherTotals = vector<TFeature>(m_channelCount-1, TFeature(m_bpo, 0.0));
Chris@50:     m_frameCount = 0;
Chris@47: }
Chris@47: 
Chris@47: template<typename T>
Chris@47: void addTo(vector<T> &a, const vector<T> &b)
Chris@47: {
Chris@69:     int n = int(b.size());
Chris@69: 
Chris@69:     for (int i = 0; i < n; ++i) {
Chris@69:         int j = (i == 0 ? n-1 : i-1);
Chris@69:         T diff = b[i] - b[j];
Chris@69:         a[i] += diff;
Chris@69:     }
Chris@47: }
Chris@47: 
Chris@47: template<typename T>
Chris@47: T distance(const vector<T> &a, const vector<T> &b)
Chris@47: {
Chris@47:     return inner_product(a.begin(), a.end(), b.begin(), T(),
Chris@47: 			 plus<T>(), [](T x, T y) { return fabs(x - y); });
Chris@47: }
Chris@47: 
Chris@55: TuningDifference::TFeature
Chris@55: TuningDifference::computeFeatureFromTotals(const TFeature &totals) const
Chris@47: {
Chris@47:     if (m_frameCount == 0) return totals;
Chris@47:     
Chris@47:     TFeature feature(m_bpo);
Chris@69:     double max = 0.0;
Chris@47: 
Chris@47:     for (int i = 0; i < m_bpo; ++i) {
Chris@47: 	double value = totals[i] / m_frameCount;
Chris@69: 	feature[i] = value;
Chris@69:         if (fabs(value) > max) {
Chris@69:             max = fabs(value);
Chris@69:         }
Chris@47:     }
Chris@47: 
Chris@69:     if (max > 0.0) {
Chris@50:         for (int i = 0; i < m_bpo; ++i) {
Chris@69:             feature[i] /= max;
Chris@50:         }
Chris@47:     }
Chris@47:     
Chris@47:     return feature;
Chris@47: }
Chris@47: 
Chris@47: Chromagram::Parameters
Chris@55: TuningDifference::paramsForTuningFrequency(double hz) const
Chris@47: {
Chris@47:     Chromagram::Parameters params(m_inputSampleRate);
Chris@47:     params.lowestOctave = 2;
Chris@47:     params.octaveCount = 4;
Chris@47:     params.binsPerOctave = m_bpo;
Chris@47:     params.tuningFrequency = hz;
Chris@47:     params.atomHopFactor = 0.5;
Chris@47:     params.window = CQParameters::Hann;
Chris@47:     return params;
Chris@47: }
Chris@47: 
Chris@55: TuningDifference::TFeature
Chris@55: TuningDifference::computeFeatureFromSignal(const Signal &signal,
Chris@55:                                            double hz) const
Chris@47: {
Chris@47:     Chromagram chromagram(paramsForTuningFrequency(hz));
Chris@47: 
Chris@47:     TFeature totals(m_bpo, 0.0);
Chris@47: 
Chris@47:     cerr << "computeFeatureFromSignal: hz = " << hz << ", frame count = " << m_frameCount << endl;
Chris@47:     
Chris@47:     for (int i = 0; i < m_frameCount; ++i) {
Chris@47: 	Signal::const_iterator first = signal.begin() + i * m_blockSize;
Chris@47: 	Signal::const_iterator last = first + m_blockSize;
Chris@47: 	if (last > signal.end()) last = signal.end();
Chris@47: 	CQBase::RealSequence input(first, last);
Chris@47: 	input.resize(m_blockSize);
Chris@47: 	CQBase::RealBlock block = chromagram.process(input);
Chris@47: 	for (const auto &v: block) addTo(totals, v);
Chris@47:     }
Chris@47: 
Chris@47:     return computeFeatureFromTotals(totals);
Chris@47: }
Chris@47: 
Chris@55: TuningDifference::FeatureSet
Chris@55: TuningDifference::process(const float *const *inputBuffers, Vamp::RealTime)
Chris@47: {
Chris@47:     if (m_maxDuration > 0) {
Chris@47:         int maxFrames = int((m_maxDuration * m_inputSampleRate) /
Chris@47:                             float(m_blockSize));
Chris@47:         if (m_frameCount > maxFrames) return FeatureSet();
Chris@47:     }
Chris@50: 
Chris@47:     CQBase::RealBlock block;
Chris@47:     CQBase::RealSequence input;
Chris@47: 
Chris@47:     input = CQBase::RealSequence
Chris@47:         (inputBuffers[0], inputBuffers[0] + m_blockSize);
Chris@47:     block = m_refChroma->process(input);
Chris@47:     for (const auto &v: block) addTo(m_refTotals, v);
Chris@47: 
Chris@50:     if (m_fineTuning) {
Chris@50:         m_reference.insert(m_reference.end(),
Chris@50:                            inputBuffers[0],
Chris@50:                            inputBuffers[0] + m_blockSize);
Chris@50:     }
Chris@50: 
Chris@47:     for (int c = 1; c < m_channelCount; ++c) {
Chris@50:         input = CQBase::RealSequence
Chris@50:             (inputBuffers[c], inputBuffers[c] + m_blockSize);
Chris@50:         block = m_otherChroma[c-1]->process(input);
Chris@50:         for (const auto &v: block) addTo(m_otherTotals[c-1], v);
Chris@47:     }
Chris@47:     
Chris@47:     ++m_frameCount;
Chris@47:     return FeatureSet();
Chris@47: }
Chris@47: 
Chris@55: TuningDifference::FeatureSet
Chris@55: TuningDifference::getRemainingFeatures()
Chris@47: {
Chris@47:     FeatureSet fs;
Chris@47:     if (m_frameCount == 0) return fs;
Chris@47: 
Chris@50:     m_refFeatures[0] = computeFeatureFromTotals(m_refTotals);
Chris@47: 
Chris@47:     Feature f;
Chris@47:     f.hasTimestamp = true;
Chris@47:     f.timestamp = Vamp::RealTime::zeroTime;
Chris@47:     f.values.clear();
Chris@47:     fs[m_outputs["cents"]].push_back(f);
Chris@47:     fs[m_outputs["tuningfreq"]].push_back(f);
Chris@47: 
Chris@47:     for (int c = 1; c < m_channelCount; ++c) {
Chris@47:         getRemainingFeaturesForChannel(c, fs);
Chris@47:     }
Chris@47: 
Chris@47:     return fs;
Chris@47: }
Chris@47: 
Chris@47: void
Chris@55: TuningDifference::getRemainingFeaturesForChannel(int channel,
Chris@55:                                                  FeatureSet &fs)
Chris@47: {
Chris@50:     TFeature otherFeature =
Chris@50:         computeFeatureFromTotals(m_otherTotals[channel-1]);
Chris@47: 
Chris@47:     Feature f;
Chris@47:     f.hasTimestamp = true;
Chris@47:     f.timestamp = Vamp::RealTime::zeroTime;
Chris@47: 
Chris@47:     f.values.clear();
Chris@50:     for (auto v: m_refFeatures[0]) f.values.push_back(float(v));
Chris@47:     fs[m_outputs["reffeature"]].push_back(f);
Chris@47: 
Chris@47:     f.values.clear();
Chris@47:     for (auto v: otherFeature) f.values.push_back(float(v));
Chris@47:     fs[m_outputs["otherfeature"]].push_back(f); 
Chris@47:    
Chris@50:     int rotation = findBestRotation(m_refFeatures[0], otherFeature);
Chris@47: 
Chris@47:     int coarseCents = -(rotation * 1200) / m_bpo;
Chris@47: 
Chris@47:     cerr << "channel " << channel << ": rotation " << rotation << " -> cents " << coarseCents << endl;
Chris@47: 
Chris@50:     TFeature rotatedFeature = otherFeature;
Chris@47:     if (rotation != 0) {
Chris@50:         rotateFeature(rotatedFeature, rotation);
Chris@47:     }
Chris@47: 
Chris@47:     f.values.clear();
Chris@50:     for (auto v: rotatedFeature) f.values.push_back(float(v));
Chris@47:     fs[m_outputs["rotfeature"]].push_back(f);
Chris@47: 
Chris@48:     if (m_fineTuning) {
Chris@48:     
Chris@55:         pair<int, double> fine =
Chris@55:             findFineFrequency(rotatedFeature, coarseCents);
Chris@50: 
Chris@48:         int fineCents = fine.first;
Chris@48:         double fineHz = fine.second;
Chris@47: 
Chris@48:         fs[m_outputs["cents"]][0].values.push_back(float(fineCents));
Chris@48:         fs[m_outputs["tuningfreq"]][0].values.push_back(float(fineHz));
Chris@47:     
Chris@48:         cerr << "channel " << channel << ": overall best Hz = " << fineHz << endl;
Chris@48: 
Chris@48:     } else {
Chris@48: 
Chris@48:         fs[m_outputs["cents"]][0].values.push_back(float(coarseCents));
Chris@48:         fs[m_outputs["tuningfreq"]][0].values.push_back
Chris@48:             (float(frequencyForCentsAbove440(coarseCents)));
Chris@48:     }        
Chris@47: }
Chris@47: 
Chris@50: void
Chris@55: TuningDifference::rotateFeature(TFeature &r, int rotation) const
Chris@50: {
Chris@50:     if (rotation < 0) {
Chris@50:         rotate(r.begin(), r.begin() - rotation, r.end());
Chris@50:     } else {
Chris@50:         rotate(r.begin(), r.end() - rotation, r.end());
Chris@50:     }
Chris@50: }
Chris@50: 
Chris@50: double
Chris@55: TuningDifference::featureDistance(const TFeature &ref,
Chris@55:                                   const TFeature &other,
Chris@55:                                   int rotation) const
Chris@50: {
Chris@50:     if (rotation == 0) {
Chris@50: 	return distance(ref, other);
Chris@50:     } else {
Chris@50: 	// A positive rotation pushes the tuning frequency up for this
Chris@50: 	// chroma, negative one pulls it down. If a positive rotation
Chris@50: 	// makes this chroma match an un-rotated reference, then this
Chris@50: 	// chroma must have initially been lower than the reference.
Chris@50: 	TFeature r(other);
Chris@50:         rotateFeature(r, rotation);
Chris@50: 	return distance(ref, r);
Chris@50:     }
Chris@50: }
Chris@50: 
Chris@50: int
Chris@55: TuningDifference::findBestRotation(const TFeature &ref,
Chris@55:                                    const TFeature &other) const
Chris@50: {
Chris@50:     map<double, int> dists;
Chris@50: 
Chris@50:     int maxRotation = (m_bpo * m_maxSemis) / 12;
Chris@50: 
Chris@50:     for (int r = -maxRotation; r <= maxRotation; ++r) {
Chris@50: 	double dist = featureDistance(ref, other, r);
Chris@50: 	dists[dist] = r;
Chris@50:     }
Chris@50: 
Chris@50:     int best = dists.begin()->second;
Chris@50: 
Chris@50:     return best;
Chris@50: }
Chris@50: 
Chris@50: pair<int, double>
Chris@55: TuningDifference::findFineFrequency(const TFeature &rotatedOtherFeature,
Chris@55:                                     int coarseCents)
Chris@50: {
Chris@50:     int coarseResolution = 1200 / m_bpo;
Chris@50:     int searchDistance = coarseResolution/2 - 1;
Chris@50: 
Chris@50:     int bestCents = coarseCents;
Chris@50:     double bestHz = frequencyForCentsAbove440(coarseCents);
Chris@50: 
Chris@50:     cerr << "findFineFrequency: coarse frequency is " << bestHz << endl;
Chris@50:     cerr << "searchDistance = " << searchDistance << endl;
Chris@50: 
Chris@50:     double bestScore = 0;
Chris@50:     bool firstScore = true;
Chris@50:     
Chris@50:     for (int sign = -1; sign <= 1; sign += 2) {
Chris@50: 	for (int offset = (sign < 0 ? 0 : 1);
Chris@50:              offset <= searchDistance;
Chris@50:              ++offset) {
Chris@50: 
Chris@50: 	    int fineCents = coarseCents + sign * offset;
Chris@50: 	    double fineHz = frequencyForCentsAbove440(fineCents);
Chris@50: 
Chris@50: 	    cerr << "trying with fineCents = " << fineCents << "..." << endl;
Chris@50: 
Chris@50:             // compare the rotated "other" chroma with a reference
Chris@50:             // chroma shifted by the offset in the opposite direction
Chris@50: 
Chris@50:             int compensatingCents = -sign * offset;
Chris@50:             TFeature compensatedReference;
Chris@50: 
Chris@50:             if (m_refFeatures.find(compensatingCents) == m_refFeatures.end()) {
Chris@50:                 double compensatingHz = frequencyForCentsAbove440
Chris@50:                     (compensatingCents);
Chris@50:             
Chris@50:                 compensatedReference = computeFeatureFromSignal
Chris@50:                     (m_reference, compensatingHz);
Chris@50: 
Chris@50:                 m_refFeatures[compensatingCents] = compensatedReference;
Chris@50: 
Chris@50:             } else {
Chris@50: 
Chris@50:                 compensatedReference = m_refFeatures[compensatingCents];
Chris@50:             }
Chris@50: 
Chris@50: 	    double fineScore = featureDistance(compensatedReference,
Chris@50:                                                rotatedOtherFeature,
Chris@50:                                                0); // we are rotated already
Chris@50: 
Chris@50: 	    cerr << "fine offset = " << offset << ", cents = " << fineCents
Chris@50: 		 << ", Hz = " << fineHz << ", score " << fineScore
Chris@50: 		 << " (best score so far " << bestScore << ")" << endl;
Chris@50: 	    
Chris@50: 	    if ((fineScore < bestScore) || firstScore) {
Chris@50: 		cerr << "is good!" << endl;
Chris@50: 		bestScore = fineScore;
Chris@50: 		bestCents = fineCents;
Chris@50: 		bestHz = fineHz;
Chris@50:                 firstScore = false;
Chris@50: 	    } else {
Chris@50: 		break;
Chris@50: 	    }
Chris@50: 	}
Chris@50:     }
Chris@50:     
Chris@50:     return pair<int, double>(bestCents, bestHz);
Chris@50: }
Chris@50: