[Ffmpeg-devel] Re: crop & pad (again)

[Luca Abeni]

Hi Baptiste,

sorry for the late reply: busy as usual at work...

On Wed, 2006-04-05 at 16:48 +0200, Baptiste COUDURIER wrote:
[...]
> It should be, however It seems it does not for me. Current cvs works
> though. It seems to pad correctly but bottom of the picture is cropped.
> Final resolution is the same. However cropping alone does work.
Ok, I think I see the bug now (files produced by output_example are not
very good for this kind of testing :)
Sorry for seeing it after your first mail.

I think the bug is incrop-pad-simplify.diff and there just is some
uninitialized variable there... I'm investingating the problem and I
will post an updated patch later.

Thanks again for testing the patches and finding the problem.

> > [...]
> >> -croptop 32 -padtop 32 -s 720x576 should crop by 32 pad those 32 and
> >> finally rescale to 720x576. Is that actual behaviour Luca ?
> > This used to generate a 720x608 picture (because it crops 32 lines, then
> > rescales to 720x576, and then pads 32 lines, so we obtain 576 + 32
> > lines). This seems to be the expected behaviour (at least, this is what
> > I've been told on this mailing list). My patches leave this behaviour
> > unchanged - modulo bugs :) I just tried, and the behaviour seems to be
> > unchanged.
> 
> Yes. I just think about it and IMHO it is more intuitive. "-s" should
> set the output resolution whatever cropping/padding you apply on the
> picture. What is your opinion about that ?
I do not know :)
There are some things that I find strange (for example: the order of
"-s" and "-crop*" matters, but the order of "-s" and "-pad*" does not),
but I am reluctant to change ffmpeg behaviour...
At least, I think that a patch changing the behaviour of the "-pad*" and
"-crop*" option should be independent from this patchset.

I'd like to hear the opinion of other people using pad, crop & friends.

[...]
> Btw, I notice that any of the padding/cropping/scaling action should
> alter aspect ratio set on the picture (reset or alter), which atm is not
> done.
I see... I do not know much about the aspect ratio stuff, so I hope
other people can comment on this

			Thanks,
				Luca
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