[MPlayer-dev-eng] Enhanced cropdetect code

Reimar Döffinger Reimar.Doeffinger at stud.uni-karlsruhe.de
Mon Jul 7 18:56:09 CEST 2008

On Sun, Jul 06, 2008 at 04:53:58PM -0500, Roger Heflin wrote:
> And I had not heard the "0-th order entropy estimation" as a name for it, I 
> heard about it 15+ years ago in an image processing class used in reference to 
> compression algorithms, and it is somewhat useful for estimating how well (in 
> general) things could be compressed, and would run at disk speed-which at the 
> time was much much faster than compression algorithms.

Well, it is called 0-th order because it only estimates the compression
in case each symbol is coded independently, i.e. the context in which
the bytes appear is completely disregarded. As such it is not very
realistic with any real compression algorithm, though it is nicely
fast and simple (e.g. with this method, the sequence 00001111 and 00101101 would
be estimated to have the same entropy/"compressability" which does not
quite match reality).

Reimar Döffinger

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