[Ffmpeg-devel] FLAC encoder

Justin Ruggles jruggle
Sat May 27 06:31:46 CEST 2006

Michael Niedermayer wrote:
> the number of bits for a single symbol is (data>>k) + k + 1 for all symbols
> n to m its obviously (m-n)*(k+1) + sum of (data[i]>>k)
> and "sum of (data[i]>>k)" is just the sum of the corresponding partial sums
> for that area

So is all that partial sums calculation just to speed up calculation of
"sum of (data[i]>>k)" ?  If so, I can easily optimize the rest and go
back to the partial sums stuff once I understand better how it works.

I have already done some simple optimizations.  My results seem too
staggering to be true.  I seem to have knocked off another 30% in
encoding time for the highest compression level.  That makes it now 60%
faster than libFLAC...  Now I'm worried it's just my machine.  Can
anyone else confirm similar results of 30% faster than "flac -8" with
the version I posted earlier?


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