Changeset 94029 in webkit

Timestamp:

Aug 29, 2011, 4:35:40 PM (15 years ago)

Author:

cevans@google.com

Message:

Merge 94002
BUG=93978
Review URL: ​http://codereview.chromium.org/7793016

Location:

branches/chromium/835/Source/WebCore/webaudio

Files:

• RealtimeAnalyser.cpp (modified) (5 diffs)
• RealtimeAnalyser.h (modified) (1 diff)

branches/chromium/835/Source/WebCore/webaudio/RealtimeAnalyser.cpp

@@ -50 +50 @@
 
 const unsigned RealtimeAnalyser::DefaultFFTSize = 2048;
+// All FFT implementations are expected to handle power-of-two sizes MinFFTSize <= size <= MaxFFTSize.
+const unsigned RealtimeAnalyser::MinFFTSize = 128;
 const unsigned RealtimeAnalyser::MaxFFTSize = 2048;
 const unsigned RealtimeAnalyser::InputBufferSize = RealtimeAnalyser::MaxFFTSize * 2;
@@ -83 +85 @@
     unsigned log2size = static_cast<unsigned>(log2(size));
     bool isPOT(1UL << log2size == size);
-    
-    if (!isPOT || size > MaxFFTSize) {
+
+    if (!isPOT || size > MaxFFTSize || size < MinFFTSize) {
         // FIXME: It would be good to also set an exception.
         return;
@@ -90 +92 @@
 
     if (m_fftSize != size) {
-        m_analysisFrame = adoptPtr(new FFTFrame(m_fftSize));
-        m_magnitudeBuffer.allocate(size);
+        m_analysisFrame = adoptPtr(new FFTFrame(size));
+        // m_magnitudeBuffer has size = fftSize / 2 because it contains floats reduced from complex values in m_analysisFrame.
+        m_magnitudeBuffer.allocate(size / 2);
         m_fftSize = size;
     }
@@ -166 +169 @@
     m_analysisFrame->doFFT(tempP);
 
-    size_t n = DefaultFFTSize / 2;
-
     float* realP = m_analysisFrame->realData();
     float* imagP = m_analysisFrame->imagData();
@@ -184 +185 @@
     // Convert the analysis data from complex to magnitude and average with the previous result.
     float* destination = magnitudeBuffer().data();
-    for (unsigned i = 0; i < n; ++i) {
+    size_t n = magnitudeBuffer().size();
+    for (size_t i = 0; i < n; ++i) {
         Complex c(realP[i], imagP[i]);
         double scalarMagnitude = abs(c) * MagnitudeScale;        

branches/chromium/835/Source/WebCore/webaudio/RealtimeAnalyser.h

@@ -71 +71 @@
 
     static const unsigned DefaultFFTSize;
+    static const unsigned MinFFTSize;
     static const unsigned MaxFFTSize;
     static const unsigned InputBufferSize;