Autres/audacity
1
0
Fork 0
mirror of https://github.com/cookiengineer/audacity synced 2026-02-05 19:21:59 +01:00
Code Issues Releases Wiki Activity

Code cleanup: removed the old real FFT code not used since at least 2009.

Browse Source 
I confirmed that the currently used real FFT code in RealFFTf.cpp is faster
than the old one with a quick benchmark that calls PowerSpectrum() on 4-minute
audio file, with different sizes of computation windows:

Window_size: 256 method: new FFT time_s: 0.393
Window_size: 256 method: old FFT time_s: 1.065
Window_size: 1024 method: new FFT time_s: 0.38
Window_size: 1024 method: old FFT time_s: 0.958
Window_size: 4096 method: new FFT time_s: 0.413
Window_size: 4096 method: old FFT time_s: 1.084
Window_size: 16384 method: new FFT time_s: 0.518
Window_size: 16384 method: old FFT time_s: 1.338
Window_size: 65536 method: new FFT time_s: 0.655
Window_size: 65536 method: old FFT time_s: 1.524
Window_size: 262144 method: new FFT time_s: 0.735
Window_size: 262144 method: old FFT time_s: 1.873
This commit is contained in:
Raphaël Marinier
2016-06-25 16:23:56 +02:00
parent cf79f91da0
commit 6ac68db5be
10 changed files with 8 additions and 210 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
src/Spectrum.cpp
View File

@@ -52,11 +52,7 @@ bool ComputeSpectrum(const float * data, int width,
if (autocorrelation) {
// Take FFT
#ifdef EXPERIMENTAL_USE_REALFFTF
RealFFT(windowSize, in, out, out2);
#else
FFT(windowSize, false, in, NULL, out, out2);
#endif
// Compute power
for (i = 0; i < windowSize; i++)
in[i] = (out[i] * out[i]) + (out2[i] * out2[i]);
@@ -68,12 +64,7 @@ bool ComputeSpectrum(const float * data, int width,
in[i] = powf(in[i], 1.0f / 3.0f);
// Take FFT
#ifdef EXPERIMENTAL_USE_REALFFTF
RealFFT(windowSize, in, out, out2);
#else
FFT(windowSize, false, in, NULL, out, out2);
#endif
}
else
PowerSpectrum(windowSize, in, out);