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Re: Video with transparent background?

To: REALbasic NUG <realbasic-nug at lists dot realsoftware dot com>
Subject: Re: Video with transparent background?
From: Tom Benson <tombenson at mac dot com>
Date: Mon, 30 Jul 2007 13:48:07 +1000
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Delivered-to: realbasic-nug at lists dot realsoftware dot com
References: <676C9BC3-EAFC-468F-8DD0-633381E3A63C at bebosoft dot com>
Chroma Key rendering would be tricky at best in pure RB, and you'd  
need to make sure your footage is filmed against a key blue/green  
backdrop.

I'm pretty sure core graphics/core animation under OS X has a built  
in routine for handling this (as well as difference frame rendering  
where QT only renders pixels that are significantly different from a  
reference frame), but I'm unsure how to access them from within RB.  
(+ core animation is not even publicly available yet).

Does this need to be in real time??

If not you could do a frame by frame render, where you use a "key"  
reference frame and then composite it with your video source, over- 
painting all of the static pixels in each video frame with the  
corresponding pixels from the reference frame. This could be VERY cpu  
intensive though.

- Tom





On 30/07/2007, at 11:56 AM, Giuseppe Farese wrote:

> Hello:
>
> For an application I'm working on, I need a window with a video and
> it should have a transparent background, so I can see only the moving
> object in the movie (the face of the person offering help) and the
> background of the movie transparent.
>
> I know how to do it with images in order to create not rectangular
> windows, however I would like to know if anyone can point me out on
> how to do it with a video.
>
>
> Regards,
>
>
> Giuseppe Farese
>
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