[MEncoder-users] cropdetect cuts off bottom of subtitles

RC rcooley at spamcop.net
Sat Jan 21 22:52:56 CET 2006

On Sat, 21 Jan 2006 14:47:08 +0000
Raphael <mencoder at lesshaste.plus.com> wrote:

> > But if you cropdetect the same part you are encoding, and the source
> > is a dvd (so  no random noise) then surely it should just scan from
> > the bottom and  top (and left and right) until it hits something
> > non-black.

Yes, although it might just ignore the subtitles as noise.  Or perhaps
it's finding the right dimentions, and the rounding is just
(unfortunately) cutting off (up to) 7 lines off the bottom, which cuts
off the bottom of your subtitles.

> > You  should then get the minimum and maximum in the
> > appropriate directions  rounded so that you don't chop any of the
> > film out.

No, it doesn't round the numbers up, always down.  It's that simple.  If
you don't want it to do that, you can change the default action of
cropdetect.  See the man page.

However, if you disable rounding, make sure you use scale to make the
final dimentions even multiples of 16 before encoding.

> It occurs to me (after talking on IRC) that maybe cropdetect doesn't 
> actually store the maximum lit area it ever finds. 

If you watch the output of cropdetect for a while, you'll see that this
obviously isn't true.  The dimentions cropdetect outputs NEVER decrease.

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