[FFmpeg-devel] [PATCH] ffv1enc: better heuristic to calculate initial states

[Peter B.]

Quoting Michael Niedermayer <michaelni at gmx.at>:

> Slightly improves compression of 2pass files

I've ran tests on 2 files:
1) 10 minutes VHS
2) concatenated version of 4SIF YUV422 files from Derf's collection

With these parameters:
coder=1, context=1, slices=24, slicecrc=1 (for both GOP=1 and GOP=300).

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Patched version produces the following size-%, compared to unpatched:

Video 1 (10 minute VHS):
99,999611616% (gop=1)
99,999579233% (gop=300)

Video 2 (Concat Derf 422 4sif):
99,997673223% (gop=1)
99,997550287% (gop=300)
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I've also verified that all produced files have matching framemd5  
checksums with the original.


Pb