[FFmpeg-devel] [PATCH 1/5] libavcodec: Implementation of 32 bit fixed point FFT

Zeljko Lukac Zeljko.Lukac at imgtec.com
Fri Jun 21 16:09:52 CEST 2013

Rockboxs fft is 10% faster, but this is due to lower accuracy of multiplication (with each multiplication they loose 1 bit of accuracy compared to our implementation). If both ffts use the same multiplication routines then our fft is 3-4% faster (measured on PC and MIPS platform). This holds for plain C versions of both ffts. We expect that increased accuracy can be achieved without speed penalty when assembly optimizations are applied.


From: Michael Niedermayer [michaelni at gmx.at]
Sent: Tuesday, June 18, 2013 6:56 PM
To: FFmpeg development discussions and patches
Cc: Mirjana Vulin; Nedeljko Babic; Zeljko Lukac; Bojan Zivkovic
Subject: Re: [FFmpeg-devel] [PATCH 1/5] libavcodec: Implementation of 32 bit fixed point FFT

On Mon, Jun 03, 2013 at 04:11:12PM +0200, Nedeljko Babic wrote:
> From: Nedeljko Babic <nbabic at mips.com>
> Iterative implementation of 32 bit fixed point split-radix FFT.
> Max FFT that can be calculated currently is 2^12.

How does this compare to: rockboxs fixed point fft


That is, which is faster ?
iam asking because I want the faster one of the 2 :)

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

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