[MPlayer-dev-eng] [PATCH] Enhanced Cropdetect Code - 0th Order Entropy

[Roger Heflin]

This code is to add the ability to detect junk added around original 4:3 content 
that are broadcast in 16:9 format with bars that contain slowly moving logos 
around them that defeats the current cropdetect code.

I believe it follows all coding standards, but it would not surprise me if I 
missed something.

As the code is done, the old functionality appears to work just like it did 
before, the entropy part is default disabled.

I have not tested the 4 bpp part of the case statement as I don't believe have I 
have any video of that type to test with, the 1 bpp test all worked as expected 
(old behavior worked if entropy was set to -1 (default off)), and new behavior 
worked if entropy was set to a value and the limit was set to (-1) off.

New manpage excerpt to go with the code:

       cropdetect[=limit:round:entropy]
               Calculates  necessary  cropping parameters and prints the recom-
               mended parameters to stdout.   The crop is the  Boolean  AND  of
               the 2 methods (unless entropy or limit is disabled by setting it
               to -1), if both are on then both must want it to be cropped  for
               it to be cropped, so turning off one is probably wise.
                  <limit>
                       Threshold,  which  can  be optionally specified from off
                       (-1) to nothing (0) to everything (255) (default: 24).
                  <round>
                       Value which the width/height should be divisible by (de-
                       fault:  16).   The  offset  is automatically adjusted to
                       center the video.  Use 2 to  get  only  even  dimensions
                       (needed  for  4:2:2 video).  16 is best when encoding to
                       most video codecs.
                  <entropy>
                       A measure of randomness, the lower the number  the  less
                       random.  It can be used to remove annoying borders added
                       to 4:3 videos that are filled out to widescreen.   Valid
                       values  are  -1 (off) to 0 (nothing) to 255.  Default is
                       -1 (off), a reasonable value  that  works  for  my  case
                       seems  to  be in the 140 range (140 is equivalent to en-
                       tropy of 4.75 bits).

If someone believes this change warrants an entry in the AUTHORS file that 
please add an entry.

		Comments?
		Roger
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