[MEncoder-users] cropdetect cuts off bottom of subtitles
mencoder at lesshaste.plus.com
Sat Jan 21 15:35:49 CET 2006
> On Fri, 20 Jan 2006 20:03:20 +0000
> Raphael <mencoder at lesshaste.plus.com> wrote:
>> The part that I chopped out (120 seconds from the beginning) is the
>> same part as I am testing. So shouldn't cropdetect work on that 120
>> seconds at least?
> No. Any number of things can fool cropdetect. Logos and all-black
> scense tend to do a good job of that.
That is very odd. I understand that if you cropdetect one part and then
encode another it can obviously get it wrong. 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. You should then get the
minimum and maximum in the appropriate directions rounded so that you
don't chop any of the film out.
>> Also, shouldn't cropdetect round so that you may
>> add a bit of border rather than risking chopping out important parts
>> of the film?
> No. Leaving any black border will hurt video compression
Oh well.. More fascinating mencoder oddities to learn about :)
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