[FFmpeg-devel] donation for snow

Jason Garrett-Glaser darkshikari
Fri Nov 7 01:31:41 CET 2008

> Do you have any comparision data ? I would, too, be interested in having
> these comparisions, also knowing which jp2k encoder was used, test
> material, etc...

I remember being linked to a paper on the topic a while back which had
the numbers I was using (though I don't remember them exactly).
However, I don't trust PSNR anyways, and if you wanted to do a real
comparison, I would say that a visual test would be the only one worth
bothering with.

Tests that use extremely low file sizes are also rather unreasonable,
because once one reaches a certain level of detail loss, one is better
off encoding at a lower resolution to begin with.  Last I recall they
did a test of JPEG-2K against JPEG (I think?) with visual (rather than
PSNR) comparisons, and the threshold at which JPEG2K began to win out
was something like 40:1 or 80:1 compression ratio--at which point they
found it was better to just lower the resolution instead.

Dark Shikari

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