[Ffmpeg-devel] FLAC encoder

Benjamin Larsson banan
Fri Jun 2 09:15:52 CEST 2006

Justin Ruggles wrote:

>I wrote:
>>Well, the FLAC encoder is getting better by the day.  I'll post some
>>results some time soon of my most recent version, which has marked
>>improvement in compression.
>Here are some current results.  The latest version is here:
>I still haven't integrated with FFmpeg...that's coming soon though.  The
>biggest improvement I have made is the application of a window function
>before calculating the LPC coefficients.  After testing several
>different window types, I found that for most audio clips, either the
>Hamming window or the Bartlett window was the best choice.  So I changed
>the encoder to calculate LPC coefficients using each of these windows.
Regaring the choise of window, read this thread:
Hope it helps.

>Optimal LPC order estimation is done for each set, and the smaller order
>of the 2 is used along with the corresponding coeffs.  It's amazing how
>such a simple thing can increase compression so much!  I got the idea
>from a general description of MPEG-4 ALS.  It could be patented for all
>I know...
>If anyone wants to do tests with the clip I used for the test below:
Benjamin Larsson

"incorrect information" is an oxymoron. Information is, by definition, factual, correct.

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