[gst-devel] [RFC] Videomixer/Imagemixer

Benjamin Otte in7y118 at public.uni-hamburg.de
Thu Mar 17 08:19:34 CET 2005

On Wed, 16 Mar 2005, Gergely Nagy wrote:

> In whatever way videomixer is implemented, there must be a way to set
> the properties of the different streams that get merged to the
> background, on a per-stream basis (ie, blend this at 10,10, with an
> opacity of 1.0, then this at 0, 200 at opacity 0.75, and so on).
> In current videomixer, this is done by having properties on the sink
> pads of the mixer. It works, but I don't really like that.
> Another option is to send property changes along the buffer (and then
> videomixer stores those settings, and reuses them when a buffer without
> xpos/ypos properties arrives). This doesn't seem clean enough either.
> Yet another option is to invent an event for this. This might work
> especially well when videomixer would be implemented as a bin,
> containing a set of stacked imagemixer elements.
> And the last option I see, is to create an API specific to videomixer to
> do this.
> So, the question boils down to: what would people prefer, videomixer
> being derived from imagemixer, or a bin of imagemixers? And in what way
> should the properties of blending be changeable?
What I would prefer is something that works the same way as Stefan's
polyphonic elements stuff (see other thread on this list and the wiki
page listed therein).


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