Fix time offset in key and beat analysis

src/analyzer/plugins/buffering_utils.cpp

@@ -1,15 +1,20 @@
 #include "analyzer/plugins/buffering_utils.h"
 
 #include "util/math.h"
+#include "util/sample.h"
+
+#include <string.h>
 
 namespace mixxx {
 
 bool DownmixAndOverlapHelper::initialize(size_t windowSize, size_t stepSize, WindowReadyCallback callback) {
-    m_buffer.resize(windowSize);
+    m_buffer.assign(windowSize, 0.0);
     m_callback = callback;
     m_windowSize = windowSize;
     m_stepSize = stepSize;
-    m_bufferWritePosition = 0;
+    // make sure the first frame is centered into the fft window. This makes sure
+    // that the result is significant starting fom the first step.
+    m_bufferWritePosition = windowSize / 2;
     return m_windowSize > 0 && m_stepSize > 0 &&
             m_stepSize <= m_windowSize && callback;
 }
@@ -57,4 +62,4 @@ bool DownmixAndOverlapHelper::finalize() {
     return true;
 }
 
-}
+}

src/track/keyfactory.cpp

@@ -98,7 +98,7 @@ Keys KeyFactory::makePreferredKeys(
             pChange->set_key(it->first);
             pChange->set_frame_position(frame);
         }
-        key_map.set_global_key(KeyUtils::calculateGlobalKey(key_changes, iTotalSamples));
+        key_map.set_global_key(KeyUtils::calculateGlobalKey(key_changes, iTotalSamples, iSampleRate));
         key_map.set_source(mixxx::track::io::key::ANALYZER);
         Keys keys(key_map);
         keys.setSubVersion(subVersion);

src/track/keyutils.cpp

@@ -395,7 +395,7 @@ ChromaticKey KeyUtils::scaleKeySteps(ChromaticKey key, int key_changes) {
 
 // static
 mixxx::track::io::key::ChromaticKey KeyUtils::calculateGlobalKey(
-    const KeyChangeList& key_changes, const int iTotalSamples) {
+    const KeyChangeList& key_changes, const int iTotalSamples, int iSampleRate) {
     const int iTotalFrames = iTotalSamples / 2;
     QMap<mixxx::track::io::key::ChromaticKey, double> key_histogram;
 
@@ -413,7 +413,7 @@ mixxx::track::io::key::ChromaticKey KeyUtils::calculateGlobalKey(
     qDebug() << "Key Histogram";
     for (auto it = key_histogram.constBegin();
          it != key_histogram.constEnd(); ++it) {
-        qDebug() << it.key() << ":" << keyDebugName(it.key()) << it.value();
+        qDebug() << it.key() << ":" << keyDebugName(it.key()) << it.value() / iSampleRate;
         if (it.value() > max_delta) {
             max_key = it.key();
             max_delta = it.value();

src/track/keyutils.h

@@ -78,7 +78,7 @@ class KeyUtils {
     static mixxx::track::io::key::ChromaticKey guessKeyFromText(const QString& text);
 
     static mixxx::track::io::key::ChromaticKey calculateGlobalKey(
-        const KeyChangeList& key_changes, int iTotalSamples);
+        const KeyChangeList& key_changes, int iTotalSamples, int iSampleRate);
 
     static void setNotation(
         const QMap<mixxx::track::io::key::ChromaticKey, QString>& notation);