diff NoteHypothesis.cpp @ 32:c88a9972975b

Add pitch note-hypothesis class

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/NoteHypothesis.cpp	Fri Jul 13 21:40:50 2012 +0100
@@ -0,0 +1,169 @@
+/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
+/* Copyright Chris Cannam - All Rights Reserved */
+
+#include "NoteHypothesis.h"
+
+#include <cmath>
+
+#include "system/sysutils.h"
+
+namespace Turbot {
+
+NoteHypothesis::NoteHypothesis()
+{
+    m_state = New;
+}
+
+NoteHypothesis::~NoteHypothesis()
+{
+}
+
+bool
+NoteHypothesis::isWithinTolerance(Estimate s) const
+{
+    if (m_pending.empty()) {
+        return true;
+    }
+
+    // check we are within a relatively close tolerance of the last
+    // candidate
+    Estimate last = m_pending[m_pending.size()-1];
+    double r = s.freq / last.freq;
+    int cents = lrint(1200.0 * (log(r) / log(2.0)));
+    if (cents < -60 || cents > 60) return false;
+
+    // and within a slightly bigger tolerance of the current mean
+    double meanFreq = getMeanFrequency();
+    r = s.freq / meanFreq;
+    cents = lrint(1200.0 * (log(r) / log(2.0)));
+    if (cents < -80 || cents > 80) return false;
+    
+    return true;
+}
+
+bool
+NoteHypothesis::isOutOfDateFor(Estimate s) const
+{
+    if (m_pending.empty()) return false;
+
+    return ((s.time - m_pending[m_pending.size()-1].time) > 
+            RealTime::fromMilliseconds(40));
+}
+
+bool 
+NoteHypothesis::isSatisfied() const
+{
+    if (m_pending.empty()) return false;
+    
+    double meanConfidence = 0.0;
+    for (int i = 0; i < (int)m_pending.size(); ++i) {
+        meanConfidence += m_pending[i].confidence;
+    }
+    meanConfidence /= m_pending.size();
+
+    int lengthRequired = 10000;
+    if (meanConfidence > 0.0) {
+        lengthRequired = int(2.0 / meanConfidence + 0.5);
+    }
+
+    return ((int)m_pending.size() > lengthRequired);
+}
+
+bool
+NoteHypothesis::accept(Estimate s)
+{
+    bool accept = false;
+
+    switch (m_state) {
+
+    case New:
+        m_state = Provisional;
+        accept = true;
+        break;
+
+    case Provisional:
+        if (isOutOfDateFor(s)) {
+            m_state = Rejected;
+        } else if (isWithinTolerance(s)) {
+            accept = true;
+        }
+        break;
+        
+    case Satisfied:
+        if (isOutOfDateFor(s)) {
+            m_state = Expired;
+        } else if (isWithinTolerance(s)) {
+            accept = true;
+        }
+        break;
+
+    case Rejected:
+        break;
+
+    case Expired:
+        break;
+    }
+
+    if (accept) {
+        m_pending.push_back(s);
+        if (m_state == Provisional && isSatisfied()) {
+            m_state = Satisfied;
+        }
+    }
+
+    return accept;
+}        
+
+NoteHypothesis::State
+NoteHypothesis::getState() const
+{
+    return m_state;
+}
+
+NoteHypothesis::Estimates
+NoteHypothesis::getAcceptedEstimates() const
+{
+    if (m_state == Satisfied || m_state == Expired) {
+        return m_pending;
+    } else {
+        return Estimates();
+    }
+}
+
+double
+NoteHypothesis::getMeanFrequency() const
+{
+    double acc = 0.0;
+    for (int i = 0; i < (int)m_pending.size(); ++i) {
+        acc += m_pending[i].freq;
+    }
+    acc /= m_pending.size();
+    return acc;
+}
+
+NoteHypothesis::Note
+NoteHypothesis::getAveragedNote() const
+{
+    Note n;
+
+    if (!(m_state == Satisfied || m_state == Expired)) {
+        n.freq = 0.0;
+        n.time = RealTime::zeroTime;
+        n.duration = RealTime::zeroTime;
+        return n;
+    }
+
+    n.time = m_pending.begin()->time;
+
+    Estimates::const_iterator i = m_pending.end();
+    --i;
+    n.duration = i->time - n.time;
+
+    // just mean frequency for now, but this isn't at all right perceptually
+    n.freq = getMeanFrequency();
+    
+    return n;
+}
+
+}
+