[FFmpeg-soc] making moving and zooming effect

[Stefano Sabatini]

On date Wednesday 2009-11-04 18:20:10 +0100, Stefano Sabatini encoded:
> On date Wednesday 2009-11-04 17:21:04 +0200, Oleksandr Bondar encoded:
> > Thanks for the response.
> 
> Avoid top-posting on FFmpeg mailing lists, we're trying to resist
> against this (predominant) silly way to reply to text messages.
>  
> > When I got something working will put it here.
> > 
> > Have one more question.
> > 
> > Is it possible to use scale and overlay filters with dynamic values of h:w
> > for scale and x:y for overlay?
> > like it is possible in setpts filter,
> > 'setpts=AVTB/25*(N+0.05*sin(N*2*PI/25))'
> 
> Do you mean as a function of PTS or N?
> 
> For the overlay filter that should be possible by extending it, with
> the scale filter that's going to be more tricky since then you'll have
> a variable output video size, which is currently not managed by
> libavfilter.

And thinking harder at it, yes it should be possible to implement a
filter cropping a given (eventually variable) area in the input video
and scaling it to a fixed output size, for example to implement a Ken
Burns effect.

Regards.