[FFmpeg-soc] [PATCH] Implement non-positional parameters parsing and parametric expressions for the crop filter arguments

[Stefano Sabatini]

On date Monday 2009-10-05 02:19:44 +0200, Michael Niedermayer encoded:
> On Sun, Oct 04, 2009 at 10:43:21PM +0200, Stefano Sabatini wrote:
> > Hi,
> > 
> > this greatly boosts the crop filter exressivity.
> > 
> > Regards.
> 
> >  doc/vfilters.texi         |   48 +++++++++++++++++-
> >  libavfilter/vf_crop.c     |  120 ++++++++++++++++++++++++++++++++++++++++------
> >  tests/codec-regression.sh |   10 +--
> >  3 files changed, 155 insertions(+), 23 deletions(-)
> > c62412ad839dea362fbf46cb89f6d671c53e35b6  crop-use-parse-opts.patch
> > Index: ffmpeg-vfilters/ffmpeg/doc/vfilters.texi
> > ===================================================================
> > --- ffmpeg-vfilters.orig/ffmpeg/doc/vfilters.texi	2009-10-04 22:21:32.000000000 +0200
> > +++ ffmpeg-vfilters/ffmpeg/doc/vfilters.texi	2009-10-04 22:38:22.000000000 +0200
> > @@ -72,11 +72,53 @@
> >  @section crop
> >  
> >  @example
> > -./ffmpeg -i in.avi -vfilters "crop=0:0:-1:240" out.avi
> > +./ffmpeg -i in.avi -vfilters "crop= x=0 : y=0: out_w= in_w/2" out.avi
> >  @end example
> >  
> > -Crop the input video to x:y:width:height.
> > -The -1 in width or height means that dimension in the input video.
> > +Crop the input video.
> > +
> > +Parameters are specified as a list of non-positional key=value pairs
> > +separated by ``:''.
> 
> i like to note that this will lead to rejection of the patch if its
> submitted for inclusion in main svn, like it happened with vf_scale.
> The old syntax is clean and sufficient, the new is a mess.

What you call "mess" is what I call "features".

Having an expressive syntax, which lets for example to specify: "crop
at the center of the input area, an area with in_w/w and in_h/2" is a
feature which I want to support, also I found that syntax quite
readable (being explicit and thus more verbose doesn't necessarily
mean less readable).

Then I agree that the code may be simpler, but that depends on the
libraries.
 
> It is possible to allow optionally specifying the left hand sides, that
> is "x=" but that should not be mandatory and it should not be done now
> but after the current code that IS already fine is in main svn.

Fine to discuss that after integration in SVN.

So I assume is already OK to post a patch to put the crop filter
in SVN?

Regards.