Mask video OR alpha channel


I have very good result with the AviSynth Frameserver. hanks a lot for this tip.

Now I try to do something like alpha channel and masking a video.

my questions:
Is there a way to do this with videos. I used a shader first time… and when I choose black for alpha… also the black in the video is gone…

in the video theres in the beginning something like an old focus effect from an single lens reflex camera. the pictures then gets blured and blends over into the the product video… perhaps I could do this effect with a sequenz of pngs? or os there a way to work with keying colors?

the video is not rectangled… it should be masked with oval edges… i have actually no idea how to make this.

I would be very happy to get a few tips.


we had a recent thread about this.


is here an other way to add only an oval edge mask over the video?


You can take a black circle/oval (painted in GDI!?!) over your destination texture and play with blend modes. I guess its simple blend,node and set color as alpha, which sets your circle color black (0) to alpha (0).

No, is wasnt like this but quite close. I did it with a black sphere and both blend.nodes. For soft edges you have to take a static image made by Photoshop, instead of the sphere.
I attached a patch.

–>But, why is there a different result, if the order of both blend nodes ( blend advanced and simple blend) is opposite? I thought it isnt that important which order blend modes are…
Apparently it is!?!

alpha.v4p (11.0 kB)

hmmm, how to get this masked image over an background. I took the render output and tried to blend it over the backgrund image… its always transparent…

its easy to create a shader which takes two texture inputs and uses one to mask the other. i bet there is one in the shader gallery. so you could put a FileTexture (or GDITexture as mentioned above) in one input and the video into the other.

alternatively you could create an oval shaped geometry and map your video onto this. try it with e.g. Segment (EX9) .

making the outer corner soft would be also possible with the geomtry based approach: The Pillow (EX9) node shows the principle - unfortunately its only rectangular.
One could create a clever circular mesh in the shape of a double ring with the alpha of the outer ring colors set to transparent and the inner ring colors to opaque.

@frank: this isnt again this?

@oschatz: No, I was just wondering why in my simple patch (circle and background) there was a change of which one was transparent, if I changed the order of blend.node and blend(advanced).node.
If latter was first (connnected to blend(advanced)) background is white (as it is originally).
If first blend(advanced) then blend background is black. Circle is always transparent.
Thats it what confused me, as I never thought about a difference in order of blend.nodes…