[webkit-help] FFT normalization in RealtimeAnalyser
Info
info at wothke.ch
Wed Aug 13 14:02:28 PDT 2014
In order to understand the idiotic differences between the data ranges
of the AnalyzerNode's getFloatFrequencyData() and
getByteFrequencyData() APIs I finally found myself analyzing the
WebKit sources:
https://github.com/WebKit/webkit/blob/master/Source/WebCore/Modules/webaudio/RealtimeAnalyser.cpp
What surprises me there is the:
const double magnitudeScale = 1.0 / DefaultFFTSize;
which is used to normalize the FFT results (see
RealtimeAnalyser::doFFTAnalysis()).
Should the correct scaling factor not rather be: 2/actualFftSize?
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