Fix a couple of compile warnings because of unused and uninitialized variables.

[kdenlive] / src / audioscopes / ffttools.cpp

diff --git a/src/audioscopes/ffttools.cpp b/src/audioscopes/ffttools.cpp
index 2ede0fa584cb54a89788c6f9985a568d6b5807c8..3d1ae83fb624dba7639e56deca026735dbedffc7 100644 (file)
--- a/src/audioscopes/ffttools.cpp
+++ b/src/audioscopes/ffttools.cpp
@@ -228,6 +228,109 @@ void FFTTools::fftNormalized(const QVector<int16_t> audioFrame, const uint chann
 #endif
 }
 
+const QVector<float> FFTTools::interpolatePeakPreserving(const QVector<float> in, const uint targetSize, uint left, uint right, float fill)
+{
+#ifdef DEBUG_FFTTOOLS
+    QTime start = QTime::currentTime();
+#endif
+
+    if (right == 0) {
+        right = in.size()-1;
+    }
+    Q_ASSERT(targetSize > 0);
+    Q_ASSERT(left < right);
+
+    QVector<float> out(targetSize);
+
+
+    float x;
+    float x_prev = 0;
+    uint xi;
+    uint i;
+    if (((float) (right-left))/targetSize < 2) {
+        for (i = 0; i < targetSize; i++) {
+
+            // i:  Target index
+            // x:  Interpolated source index (float!)
+            // xi: floor(x)
+
+            // Transform [0,targetSize-1] to [left,right]
+            x = ((float) i) / (targetSize-1) * (right-left) + left;
+            xi = (int) floor(x);
+
+            if (x > in.size()-1) {
+                // This may happen if right > in.size()-1; Fill the rest of the vector
+                // with the default value now.
+                break;
+            }
+
+
+            // Use linear interpolation in order to get smoother display
+            if (xi == 0 || xi == (uint) in.size()-1) {
+                // ... except if we are at the left or right border of the input sigal.
+                // Special case here since we consider previous and future values as well for
+                // the actual interpolation (not possible here).
+                out[i] = in[xi];
+            } else {
+                if (in[xi] > in[xi+1]
+                    && x_prev < xi) {
+                    // This is a hack to preserve peaks.
+                    // Consider f = {0, 100, 0}
+                    //          x = {0.5,  1.5}
+                    // Then x is 50 both times, and the 100 peak is lost.
+                    // Get it back here for the first x after the peak (which is at xi).
+                    // (x is the first after the peak if the previous x was smaller than floor(x).)
+                    out[i] = in[xi];
+                } else {
+                    out[i] =   (xi+1 - x) * in[xi]
+                          + (x - xi)   * in[xi+1];
+                }
+            }
+            x_prev = x;
+        }
+    } else {
+        // If there are more than 2 samples per pixel in average, then use the maximum of them
+        // since by only looking at the left sample we might miss some maxima.
+        uint src = left;
+//         int xi_prev = 0;
+        int points;
+
+#ifdef DEBUG_FFTTOOLS
+        qDebug() << "Interpolation: Ratio over 2; using maximum interpolation";
+#endif
+
+        for (i = 0; i < targetSize; i++) {
+
+            // x:  right bound
+            // xi: floor(x)
+            x = ((float) (i+1)) / (targetSize-1) * (right-left) + left;
+            xi = (int) floor(x);
+            points = 0;
+
+            out[i] = fill;
+
+            for (; src < xi && src < (uint) in.size(); src++) {
+                if (out[i] < in[src]) {
+                    out[i] = in[src];
+                }
+                points++;
+            }
+
+//             xi_prev = xi;
+        }
+    }
+    // Fill the rest of the vector if the right border exceeds the input vector.
+    for (; i < targetSize; i++) {
+        out[i] = fill;
+    }
+
+#ifdef DEBUG_FFTTOOLS
+    qDebug() << "Interpolated " << targetSize << " nodes from " << in.size() << " input points in " << start.elapsed() << " ms";
+#endif
+
+    return out;
+}
+
 #ifdef DEBUG_FFTTOOLS
 #undef DEBUG_FFTTOOLS
 #endif