[FFmpeg-devel] [RFC] faster vp3 unpack_vlc

Mike Melanson mike
Wed Jun 4 07:00:06 CEST 2008

Reimar D?ffinger wrote:
> Hello,
> because of some user reports I downloaded the Ogg version of this:
> http://www.bigbuckbunny.org/index.php/download/ and was surprised how
> very slow it was.
> Oprofile told me, that > 40 of decoding time was spent in unpack_vlcs.
> It looks like a cache issue, since splitting one array out of the struct
> as in attached patch brings it down to 28% of total time.
> I have the feeling that this is a case where the data structure just
> plain does not match the problem, but at least it is a start.
> What are your opinions? Seems Mike is the maintainer of this file,
> what do you think?

I'm still thinking about it. Don't remember enough about the algorithm 
(allegedly, I'm mentoring an encoder this summer, too).

Do the changes work?

Are they measurably faster?

If so, great.

	-Mike Melanson

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