[gstreamer-bugs] [Bug 625722] new plugin: cheeseeffects

[GStreamer (bugzilla.gnome.org)]

https://bugzilla.gnome.org/show_bug.cgi?id=625722
  GStreamer | gst-plugins-bad | unspecified

Sebastian Dröge <slomo> changed:

           What    |Removed                     |Added
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             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1

--- Comment #15 from Sebastian Dröge <slomo at circular-chaos.org> 2010-08-01 17:58:59 UTC ---
(In reply to comment #14)
> (In reply to comment #13)
> > > It is not straightly portable to geometrictransform because it currently works
> > > with 32 bit pixels while that supports also RGB, GRAY8 and GRAY16 caps.
> > 
> > Well, the interpolation thing could be added to the geometrictransform
> > baseclass I guess. And then you could port most of these effects to that and
> > automagically get RGB, etc support :)
> > What do you think?
> 
> Sorry for my bad english, I meant that my interpolation function is not
> directly portable as is because it doesn't take video format into account right
> now and just assumes 8888 pixels, so it may take some work to do it properly.
> Anyway, I'll drop interpolation for now and port the filters to geometric
> transform. Then I'll try to find some time to port the interpolation thing too.

Doing the interpolation is essentially the same for other pixel formats... you
simply do it by component.

> > > Also I'd like to add at least two more filters, lookup table based color
> > > transforms, "heat" and "sepia". It would be great to have them in Cheese but
> > > they don't surely fit the geometrictransform plugin.
> > 
> > Yes, that's something different then. How exactly do they work? Is it just a
> > function from source color to destination color, e.g. mapping of green to blue?
> > Or does it also take the position into account?
> 
> They just map source color to output color using a lookup table. Heat and sepia
> calculate current color luminance and sample the new color from a 256 pixels
> array.
> No position involved.

How do you build the lookup table btw? It would be *really* large in the
general case.

> > Anyway, I think it might make sense to have a new plugin with a base class for
> > this and then add the heat/sepia elements as subtypes there. I guess something
> > like current cheese's "hulk" effect could be done with this too, IIRC it was
> > just adjusting the hue a bit.
> 
> Yep it just uses videobalance for that but it could very well be done this way
> too. Again, will see if time allows me to do this properly.
> Not sure there is much material for a base class, it wouldn't be that different
> from plain basetransform/videofilter.

I don't know, maybe the base class could handle the lookup table and apply it
to different color formats. And the subclasses only provide the different
lookup tables for the different effects then.

But if all these effects could be implemented with videobalance a bin around
videobalance would definitely be preffered.

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