[MPlayer-users] probably my usual stupid question of the week

[D Richard Felker III]

On Tue, Apr 20, 2004 at 03:32:01PM +0300, Jan Knutar wrote:
> 
> > Well, that's pretty much the point of this patch.  I have a script
> > that executes mplayer using cropdetect to automatically determine how
> > much to crop.  I can't take a look at the numbers and sanitize them
> > by hand. Also, doing any math in a script isn't really plesant, which
> > is why it's a patch to mplayer.
> 
> I don't really like the idea of having cropdetect output values which 
> are rounded/changed, to fit the constraints/preferences of one 
> particular encoder/colorspace/decoder chain, solely for the purpose of 
> making it a little bit easier to script with...

There are two matters. One is choosing even offsets, which is
absolutely required no matter what you'll be doing with the video
afterwards. Choosing multiples of 4 for interlaced content is also
along these lines. This should always be done.

Alinging crop size to a multiple of 16 is another matter entirely, and
is only relevant if you're going to encode the result without any
subsequent scaling, etc. This should not be done unless the user asks
for it somehow.

Rich