[FFmpeg-devel] [PATCH] Fix off-by-one error in dvdsubdec.c

Oliver Fromme oliver at fromme.com
Thu Jul 3 16:42:18 CEST 2014


Oliver Fromme wrote:
 > I recently noticed that the lowest pixel rows from VOBSUB
 > subtitles are missing.  This is particularly ugly when there
 > are letters with an outline border, it looks as if the lower
 > border of the characters is cut off.

Sorry, I forgot to include an example.  Here is a subtitle
frame before and after the patch:

http://inof.de/tmp/dvdsubdec-bug.png
http://inof.de/tmp/dvdsubdec-fixed.png

It's a German subtitle frame from "The Life of Brian".  These
files come directly from the ppm_save() debugging function of
dvdsubdec.c (converted to PNG because some web browsers don't
support PPM).

Look closely at the bottom of the frame, the problem should
be clearly visible.  It definitely is visible when the frames
are scaled to a 40" TV screen.

Best regards
   Oliver


-- 
``We are all but compressed light'' (Albert Einstein)


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