View Full Version : Bluescreening in blender

10 October 2003, 11:07 AM
I want to know if I can use Blender to make the bluescreen effect. I know you can with mesh and video/image in the background, but can this be achieved with 2 video files? I did fiddle round, trying to use the alpha over and the cross effects in the sequence editor, but my video quality was really bad. It should be possible to put up a blue (or any color) background and have that be replaced with another movie. Is that what the gamma cross does?

I have notced that there is not alot of tutorials or information regarding the sequence editor on the net, if there is, could you please direct me to it. :)

Say hi to mom for me.

10 October 2003, 05:35 PM
I'm not expert on the Sequence Editor, actually I'm quite new to it.

I guess that the trick is on the video source that you want color-key. It is a normal video or it is something rendered with Blender?

If it is a normal video then you have to find a way to add alpha information to it, you already found a way.

Now, if it is something rendered on Blender your problem is already solved.. did you notice the option called "RGBA" on the display buttons? That A means Alpha... so that alpha information is stored within the image when it is rendered.

Of course, storing the alpha inside a video isn't very practical. So, why don' t you render it to a numbered sequence of TGA images.... that sequence can then be re-loaded as an animated texture on a plane wiht a fully functional alpha channel on it :cool:

10 October 2003, 09:41 PM
Check the sequence plugin repository... you have a ets of useful plugins... if they don't work with your blender just go ask for help on forums...

Hope this helps!


10 October 2003, 02:33 AM
Hey thanks alot,

those sequence plugins are really great. :p

10 October 2003, 02:07 AM
those sequence plugins are really great

Yes, they are. Specifically for you is the Chromakey plugin. That lets you choose a colour via sliders and then you set its tolerance level for any near/neighbouring shades/colours. Havent used it of late, but it does work somewhat (a least in low res, dont know about high res, dont have time to fool around that much.).

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