[FFmpeg-devel] [patch] yadif code dump

[Michael Niedermayer]

On Fri, Dec 03, 2010 at 04:47:07PM +0100, James Darnley wrote:
> On 01/12/2010, Michael Niedermayer <michaelni at gmx.at> wrote:
> > On Sat, Nov 27, 2010 at 09:58:06PM +0100, James Darnley wrote:
> >> Subject: [PATCH 4/6] Remove unnecessary shadowed variable in yadif
> >
> > This could have performance effects and should be benchmarked
> 
> Good point.  I benched it and got the following for a 704 pixel line (luma only)
> With the shadowing:
> 1912237 dezicycles in filter_line, 260884 runs, 1260 skips
> Without:
> 1920573 dezicycles in filter_line, 260438 runs, 1706 skips
> Per pixel, with:
> 2811 dezicycles in filter_line, 268356284 runs, 79172 skips
> Without:
> 2812 dezicycles in filter_line, 268356237 runs, 79219 skips
> 
> What is more worrying is that this function takes twice as long as the
> same code in x264.  It's just ~880000 dezicycles.  What have you
> people done?  The slowdown looks to start on the second filtered frame
> (single-rate) or the third (double-rate).  That is when yadif should
> be requesting/using frames 0, 1 and 2.

is this reproduceable with different video widths?
what about the skip numbers, do they differ too?

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

No human being will ever know the Truth, for even if they happen to say it
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