[Ffmpeg-devel] [Ffmpeg-devel-old] [patch] tighter snow slicing

Yartrebo yartrebo
Wed Apr 13 21:32:29 CEST 2005

I've improved the way that slicing bands are calculated so that idwt,
decode_subband, and predict all are aligned. Speed-up is about 1%-8%
depending on resolution for my (for my P4, and with both my submitted
and my non-submitted asm code in use - AMDs will get better benefits,
while using the C code will mask much of the benefit)

I would consider this patch risky because the underlying allocation
algorithm is fairly complex; however, I have run tests on plenty of
resolutions (200x150 up to 1024x768, including odd-ball resolutions) and
it hasn't thrown any assertions in the slice_buffer collection of
functions (class if this were C++) yet. Lossless + 9/7 fails my tests,
but it fails identically to cvs version (Michael seems to be quite aware
of this fact - and it appears that 9/7 for lossless will likely be

This patch may be applied to cvs or to cvs + any combination of my
pending patches.


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