[vlc-devel] vlc: svn commit r19922 (dionoea)

Subversion daemon svn at videolan.org
Mon Apr 23 23:41:26 CEST 2007

r19922 | dionoea | 2007-04-23 23:41:25 +0200 (Mon, 23 Apr 2007) | 19 lines
Changed paths:
   M /trunk/modules/video_filter/gaussianblur.c

Yet another optimisation for the gaussian filter. This adds a compile
time option to use floats instead of integers. Performance comparison
(performance is in numbers of samples output by oprofile. Less is better)

sigma   old version (integers)       integers       floats
 2.0    556889                    466435 (-17%)  481293 (-13%)
 4.0    902749 (core maxed out)   732755 (-19%)  716070 (-21%)

I'll have to check why performance gain depends on sigma for the float
and integer version.

I'll aslo add another module (most likely named fastgaussianblur.c)
based on Frederick M. Waltz and John W. V. Miller's "An efficient
algorithm for Gaussian blur using finite-state machines" article. This
seems to be way faster (but it's doesn't allow as much granularity in
the gaussian's choice and it adds an error compared to this module).

 > http://trac.videolan.org/vlc/changeset/19922

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