[Ffmpeg-devel] SVN dump

[Dave Dodge]

On Wed, Apr 18, 2007 at 06:09:48PM -0400, Rich Felker wrote:
> On the other hand, I think some functional ideas are actually
> applicable to video processing. The video filter layer I've proposed
> [in outline form only] can actually be seen as an application of
> functional programming, whereby filter authors are requested to
> specify just the computations and the data needed to perform them,

No argument there.  Whenever I start thinking about how I'd represent
video streams and filtering/editing operations in my ideal simple
editing tool, it quickly starts looking a lot like Lisp data.

I have hazy recollection of writing a program for generating simple
stereograms, that used a Lispish design for the file describing how to
construct the image.  In fact I just found the code in an alt.sources
archive circa 1991 and it does indeed seem to be mimicking Lisp:

  (setq `mypic (CreateStringPicture
  "11    11  22222222"
  "11    11     22"
  "11    11     22"
  "11111111     22"
  "11    11     22"
  "11    11     22"
  "11    11  22222222"))

  ;; this bit of code puts a 3 pixel border around "mypic"
  (setq `my_X (add (GetPictureXsize mypic) (mul 3 2)))
  (setq `my_Y (add (GetPictureYsize mypic) (mul 3 2)))
  (setq `mypic
    (ComposePictures
      (OriginCenterInside mypic my_X my_Y)
      (CreateEmptyPicture my_X my_Y transparent)))

  ;; now draw the picture
  (setq `EdgeFill false)
  (DrawPicture mypic)

                                                  -Dave Dodge