If the pixels are exactly, and I mean exactly the same in your video without the character and your video with the character then you can use the difference keyer. If there are any compression artifacts or other differences this will not work very well.
I am assuming that you are talking about game capture.
Here is a little glossary that will help you describe your project by correctly naming the pieces.
- Foreground plate: original video of a subject where you want to remove the background in someway
- Background plate: video or an image you want to use as the replacement background
- Clean plate: an exact copy of your foreground like that does not have the foreground element
In your case the video without the character would be your "clean plate" if it is exactly identical to the video with the character except for the character.
thanks. Yes I did this before and it works to 90%...
The background completely dissappear because they are 100% identical.
But because of the character is not the same, I have now a 20%-50% shader from the background in front of my character...
So it is now perfect where it wasn't but the character that was perfect isn't after.
Is there a option to disable it that the background overlays the character when there isn't the same pixels?
I would have to see the shot. Refine matte is probably what you are after. If it's game play video the color on the edges is probably very poorly blended with the background and the bit depth and anti aliasing is probably very bad and inconsistent so you're probably in trouble.
I already tried it but it doesen't work.
You can save the two images and try it on your own.
When I import them into AE and use the difference effect, all around the angel is perfect. But now everything from the letters "test" that was behind the angel is now in front of the angel... and I don't know how to fix it.
If you're working in 3D, make sure the text layer's Y-position is behind the angel from the perspective of the camera.
If you're working in 2D, make sure the text layer is below the angel layer(s) in the comp.
In either case, this is REALLY basic AE knowledge, and you should take a step back: