Chroma key

[CavalloPazzo]

Is there a filter to do "Chroma key" for avisynth or Virtualdub? I haven't found none.

[DDogg]

CavalloPazzo, that is a very broad and open ended question. It might be better if you took some time and clearly expressed what you are trying to do.

I assume you want to take video 1, say a person shot against a lime green background and video2, say a background video of the moon and combine them in such a way that all the green of video1 is replaced by video2 so that you got a guy looking like he is on the moon.

Assuming my interpretation of your question is correct, maybe somebody can comment. I certainly don't have the expertise to do it, but would not be at all surprised if one of the gurus here could show you how to do it. That would be very cool indeed. Consider my post one of facilitation.

[sh0dan]

Unless you want a quite bad chroma keying, you are probably better off using software that has dedicated filters for this. Proper chromakeying is not an easy task and it requires many adjustments.

AfterEffects (using ultimatte), Combustion, Shake and similar compositing applications are much more suited for a task like this.

[WarpEnterprises]

The only filter coming close to that is ColorKeyMask which creates a alpha-Mask depending on the color.

[poptones]

colorkeymask will do a fine job, but to do proper chroma-keying you need two things:

1) multiple mask layers (for proper antialiased edges)
2) excellent source material.

Anything passed through a YUV codec is going to give you poor results because of the blurred chroma info. You're doomed to either live with blurry edges... or green edges. Fine for TV work, terrible for film.

[CavalloPazzo]

Thanks all,
What I have to do is very simple... I have a video with a person on foreground and a white background and I want to change the background in blu.
Il try ColorKeyMask, or some software Shodan suggested.
Thanks