[FFmpeg-devel] [PATCH] libavfilter-soc: Make the overlay filter able to align to opposite edges

[Robert Swain]

Martin Storsj? wrote:
> On Wed, 6 May 2009, Michael Niedermayer wrote:
> 
>> On Wed, May 06, 2009 at 02:47:16PM +0300, Martin Storsj? wrote:
>>> The attached patch makes the overlay filter able to align the overlaid 
>>> stream to the opposite edges, by setting negative offsets. E.g., 
>>> overlay=-1:-1 sets the overlay at one pixel from the bottom right corner.
>> i would have thought negtaive offsets would cause a overlay to hang out
>> at the left/top aka be cliped.
> 
> That would probably be more logical, yes. That's not supported in the 
> overlay filter at the moment, though, but could of course be fixed later 
> (or before adding this kind of functionality).
> 
> Any suggestions on a better way of achieving this in the overlay filter's 
> parameter interface?

I think you'd have to add extra parameters to toggle the operation of 
the offsets and maintain logical functionality as Michael claimed. Maybe 
have right and bottom parameters that, when non-zero, toggle to make the 
offsets be calculated from the right/bottom.

Regards,
Rob