[FFmpeg-devel] Possible new feature: moving zoom
Mark Roberts
ffmpeg
Sat Jul 11 19:42:03 CEST 2009
Dear list!
I am planning to implement a feature I need in ffmpeg.c. We have several
recordings of theatre performances in high resolution video made with a
camcorder on a fixed stand. I would like to add a virtual hand-held
effect, that is: zoom in on the active character, follow him about the
stage, zoom out again, that sort of thing.
I would create a configuration file which states, for every frame of the
film, the rectangle I want zooming to full size. The better the config,
the better the result. For instance, if the rectangle corners follow
spline curves, the zooming will look smooth. As if filmed by a good camera
man.
Is anybody but me interested in this feature? It would consist of a
command-line option like "-zoomconfig <filename>" and some additional
clipping and rescaling in ffmpeg.c:do_video_out().
If anybody wants it, I will have to watch the identation :) otherwise I'll
just hack it and keep it to myself.
Two more cool feature could be (1) incorporating the computation of the
spline curves in ffmpeg (thus the config file need not state anything like
so many rectangles), and (2) creating the config file while watching the
film with ffplay, using the mouse.
Needless to say: all this is only possible because the ffmpeg code base is
so good. Thank you for providing it!
Any comments?
Thanks,
Mark Roberts
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