[vorbis-dev] Ogg/Vorbisreport, FFT optimizations

[Sebastian Gesemann]

Tor-Einar Jarnbjo wrote:

 > Hi Johannes,
 >
 > do you mind making the pre-sort and FFT source code available somehow? I
 > suppose it would give a performance boost to my Java based Vorbis 
decoder as
 > well.
 >
 > Tor

As far as i remember the AC3 specification (pulicly available as
A52.PDF) describes how to reduce the MDCT to a complex n/4-point
FFT (using some pre/post twiddles for reduction).

I haven't checked the vorbis reference code. Honestly, I've assumed
the encoder/decoder would already do this.

bye,
Sebastian

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