From: Simon A. Eugster <simon.eu@gmail.com>
Date: Sat, 27 Nov 2010 07:03:18 +0000 (+0000)
Subject: Some comments added
X-Git-Url: https://git.sesse.net/?a=commitdiff_plain;h=f26c07fd5d901fead8ea74490220fe5ea11f97c4;p=kdenlive

Some comments added

svn path=/trunk/kdenlive/; revision=5121
---

diff --git a/src/audioscopes/audiospectrum.cpp b/src/audioscopes/audiospectrum.cpp
index d4bb715b..f0b8cf4d 100644
--- a/src/audioscopes/audiospectrum.cpp
+++ b/src/audioscopes/audiospectrum.cpp
@@ -16,8 +16,6 @@ AudioSpectrum::AudioSpectrum(Monitor *projMonitor, Monitor *clipMonitor, QWidget
 
     m_cfg = kiss_fftr_alloc(512, 0,0,0);
 
-    m_aAutoRefresh->setChecked(true); // TODO remove
-
     m_aLin = new QAction(i18n("Linear scale"), this);
     m_aLin->setCheckable(true);
     m_aLog = new QAction(i18n("Logarithmic scale"), this);
@@ -27,7 +25,7 @@ AudioSpectrum::AudioSpectrum(Monitor *projMonitor, Monitor *clipMonitor, QWidget
     m_agScale->addAction(m_aLin);
     m_agScale->addAction(m_aLog);
 
-    m_menu->addSeparator()->setText(i18n("Scale"));;
+    m_menu->addSeparator()->setText(i18n("Scale"));
     m_menu->addAction(m_aLin);
     m_menu->addAction(m_aLog);
 
@@ -76,47 +74,56 @@ bool AudioSpectrum::isScopeDependingOnInput() const { return true; }
 bool AudioSpectrum::isHUDDependingOnInput() const { return false; }
 
 QImage AudioSpectrum::renderBackground(uint) { return QImage(); }
-QImage AudioSpectrum::renderScope(uint accelerationFactor, const QVector<int16_t> audioFrame, const int freq, const int num_channels, const int num_samples)
+QImage AudioSpectrum::renderScope(uint, const QVector<int16_t> audioFrame, const int freq, const int num_channels, const int num_samples)
 {
+    QTime start = QTime::currentTime();
     float data[512];
 
     // The resulting FFT vector is only half as long
     kiss_fft_cpx freqData[256];
 
     // Copy the first channel's audio into a vector for the FFT display
+    // (only one channel handled at the moment)
     for (int i = 0; i < 512; i++) {
         data[i] = (float) audioFrame.data()[i*num_channels];
     }
+    // Calculate the Fast Fourier Transform for the input data
     kiss_fftr(m_cfg, data, freqData);
+
 //    qDebug() << num_samples << " samples at " << freq << " Hz";
 //    qDebug() << "FFT Freq: " << freqData[0].r << " " << freqData[1].r << ", " << freqData[2].r;
 //    qDebug() << "FFT imag: " << freqData[0].i << " " << freqData[1].i << ", " << freqData[2].i;
 
-    qDebug() << QMetaObject::normalizedSignature("void audioSamplesSignal(const QVector<int16_t>&, int freq, int num_channels, int num_samples)");
 
     float max = 0;
+    float maxSignal = 0;
     float min = 1000;
     float val;
+    // Get the minimum and the maximum value of the Fourier transformed (for scaling)
     for (int i = 0; i < 256; i++) {
-        if (m_aLin->isChecked()) {
-            val = pow(pow(fabs(freqData[i].r),2) + pow(fabs(freqData[i].i),2), .5);
-        } else {
-            val = log(pow(pow(fabs(freqData[i].r),2) + pow(fabs(freqData[i].i),2), .5));
+        // sqrt(r² + i²)
+        val = pow(pow(fabs(freqData[i].r),2) + pow(fabs(freqData[i].i),2), .5);
+        if (maxSignal < val) { maxSignal = val; }
+        if (!m_aLin->isChecked()) {
+            // Logarithmic scale
+            val = log(pow(pow(fabs(freqData[i].r),2) + pow(fabs(freqData[i].i),2), .5)/512.0f);
         }
         max = (max > val) ? max : val;
         min = (min < val) ? min : val;
     }
-    qDebug() << "MAX: " << max << ", MIN: " << min;
+    qDebug() << "MAX: " << max << " (" << maxSignal << "), MIN: " << min;
 
+    // Scaling factor
     float factor = 100./(max-min);
 
+    // Draw the spectrum
     QImage spectrum(512, 100, QImage::Format_ARGB32);
     spectrum.fill(qRgba(0,0,0,0));
     for (int i = 0; i < 256; i++) {
         if (m_aLin->isChecked()) {
             val = pow(pow(fabs(freqData[i].r),2) + pow(fabs(freqData[i].i),2), .5);
         } else {
-            val = log(pow(pow(fabs(freqData[i].r),2) + pow(fabs(freqData[i].i),2), .5));
+            val = log(pow(pow(fabs(freqData[i].r),2) + pow(fabs(freqData[i].i),2), .5)/512.0f);
         }
         //val = val >> 16;
         val = factor * (val-min);
@@ -127,7 +134,7 @@ QImage AudioSpectrum::renderScope(uint accelerationFactor, const QVector<int16_t
         }
     }
 
-    emit signalScopeRenderingFinished(0, 1);
+    emit signalScopeRenderingFinished(start.elapsed(), 1);
 
     /*
     if (!fileWritten || true) {