CompuServe Messages

James, By using Alpha Split you get two images. One is the "matte" which is a white "fill" of the objects in your animation. The other is the rendered image. By laying the two seperately to tape, you have a "key" signal (alpha matte) and the "fill" your graphic image. Then using a true key, you key into the alpha matte which is digitally composited into your video. The matte cuts a video "hole" into which your animation sequence is inserted. That's the way its done except for some high end propietary systems which are able to split the channels. You do have a key signal out which can be used for graphic stills with 32 bit to cut a "hole" in your video and fill it with your graphic still. But imagine what has to happen to do it the way your are thinking about. First you would need to have an image you wanted to key into, then you need the key signal and finally a frame of animation. Now, if this isn't happening in real time, then you need a system which will display a frame insert the key signal and composite in the animation frame. This would have to be done "frame by frame". Were you thinking of running the animation once created through the Illuminator Pro in real time with say a tape deck, and have the Illuminator Pro do the keying? That is possible but where does the Illuminator Pro get its key signal when playing a tape through it, as tape decks don't support an alpha channel? This would have to be an internal luminance key. Both luminance keys and chroma keys have their drawbacks. A luminance key is unsatifactory if you have any dark areas in your image. A chroma key is unsatisfactory if you have any colors which match your key color. So the best way is to create a "flying matte" which will cut a hole into the video signal into which you can insert your animation. Neither tape nor DDR's at this time support Alpha except on high end proprietary systems. It would be nice if the PAR or the MAX provided a seperate key signal which it could read from alpha or a seperate matte like 3DS creates. This would allow you to play back animations in real time and provide a true key signal. So the long and short of it is, until tape decks support a key channel or DDR's support a key channel, you need to create an "alpha" matte seperate from your animation and run them on two seperate decks, one as the "key" and one as the "fill" and key insert them into your video. I hope this clears up your questions. -JE