On Jul 20, 2004, at 9:51 AM, andreithomaz wrote:

hello list,

I am using GEM on WindowsXP. I would like to mix videos with transparency (that is, with alpha channel). But I cann't find a codec that supports that. Do you know anyone?

You are right that video has no alpha channel so finding a video codec that supports one is nearly impossible exactly for that reason. I would suggest looking into computer graphics codecs like Apple/Adobe Animation included with Quicktime. It will include alpha when the color depth is set to 'Millions of Colors+'.

A way to solve the problem would be to show a image sequence (PNG files with 32 bit color). But, for that, I would have to transform a number into a string, and concatenate it with a string (for exemple, "frame" + number + ".png"). Is it possible to make that?

There are utilities to put image sequences into .mov or .avi containers

• I use Quicktime Pro to load the image sequence GEM writes to disk and

make it into a single .mov file. This would be a lot easier than what you propose.

cgc

thanks a lot, andrei

andreithomaz wrote:

hello list,

I am using GEM on WindowsXP. I would like to mix videos with transparency (that is, with alpha channel). But I cann't find a codec that supports that. Do you know anyone?

How do you mean that, do you just want to blend video into each other? No problem with that, you can add an alpha blending to each Gem stream. Something like

[gemhead 50] | [color 1 1 1 0.5] | [alpha] | [pix_movie] | [square 4]

makes one videotexture half transparent (the 0.5 is it), double it and put another number in gemhead, 51 maybe, for the other video.

A way to solve the problem would be to show a image sequence (PNG files with 32 bit color). But, for that, I would have to transform a number into a string, and concatenate it with a string (for exemple, "frame" + number + ".png"). Is it possible to make that?

thanks a lot, andrei

But maybe I miss the point of your mail...

Malte