[Webkit-unassigned] [Bug 113527] Add a FFT implementation using kissfft in FFTFrame

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=113527





--- Comment #5 from Raymond Toy <rtoy at chromium.org>  2013-04-03 16:04:42 PST ---
(In reply to comment #4)
> (In reply to comment #3)
> 
> Could you confirm that those numbers had the NEON flag enabled ?

The build had -mfpu=neon and -D__ARM_HAVE_NEON.  

> Also, the performance of the FFT was not a concern in this case as I needed the functionality which was not available at the time I started this work. SO I don't have currently accurate numbers as you do. I really appreciate your feedback on the performance.

Thanks for the info.

> 
> > (In reply to comment #2)
> > > (In reply to comment #1)
> > > 
> > > Thx for the feedback, could you detail "runs about half as" . Do you mean slower or faster ?
> > 
> > Sorry, that confuses me too.  To be concrete, a 1024-point complex float FFT takes 190 us with KissFFT and 89.8 us with OpenMAX on a Galaxy Nexus phone.  The ratio of KissFFT times to OpenMAX times is roughly 2 for all the orders I tried.  If the KissFFT times don't make sense to you, please let me know.  Perhaps I made a mistake in compiling it.
> > 
> > 
> > > 
> > > Thx
> > > 
> > > Alex
> > > 
> > > > (In reply to comment #0)
> > > > > This is the first step to enable WebAudio on Android.
> > > > > Adding an extra FFT implementation using kissfft in FFTFrame.
> > > > > The kissfft patch code could be found under :
> > > > > https://www.codeaurora.org/patches/quic/webtech/1602-kissfft-add-neon-optimized-routines.patch
> > > > > 
> > > > > Expected results:
> > > > > This change should be seamless as used specifically for Android OS
> > > > 
> > > > Thanks for the link and patch.  I ran some tests using your KissFFT implementation on a Galaxy Nexus phone and compared the results with https://code.google.com/p/webrtc/source/browse#svn%2Fdeps%2Fthird_party%2Fopenmax.
> > > > 
> > > > My tests show that KissFFT runs about half as the OpenMAX implementation.

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