Hello. I am using a whole load of uncompressed AVIs which contain alpha channels in a project which uses DirectShow to render these animations to the screen. Basically the animations are running too slow in their uncompressed state, and it seems it is impossible to compress an AVI which contains an alpha channel, so I have come to the following solution. For each animation in the program I am going to get a background on to which the animation would have been rendered with it's alpha channel. I am then going to decompile the animation to a series of TGA's. I am then going to put each frame on top of the background that it would be rendered on to. I am then going to recompile the alpha'less AVI. Now the only way I can think of to do this is to manually alter each frame in Photoshop, which is obviously going to be extremely time consuming. My question is, is there a quicker or possibly automated way to do this? Does Premiere (or other software) have some trick up it's sleeve whereby it will overlay every frame in an AVI over a given image? Thanks in advance for any help you can give me guys. Kind regards. Mark Coleman

Well I'm afraid this may not help but I would use Blender. It's a very flexible 3d modeller/animator/game designer/coffee maker with a video sequencer thrown in for good measure. However it's not something you can just instantly use. Learning the interface can take time so maybe not the perfect solution for this task. But the video sequencer can easily overlay avis or numbered sequences of tga/png's etc & spit out the results to an avi.
Hmm can you really not compress with an alpha channel? I guess it must depend on what codec you're using really - look around.

Trust me, I have looked for over a month now, plus I have spoken to some guys at Adobe, it is impossible to compress an AVI with alpha. There are a few codec's which claim to support alpha (such as HuffyUV and Softlab-NSK) but upon further inspection they actually don't.

I will have a look at blender3d, perhaps I could PM you with one or two questions?

Thanks for the pointer.

Kind regards.

Mark Coleman

Hmm damn you're right no alpha. That really sucks. BUT quicktime mov's do support alpha channels (just tested). Would they be an option to use? If so throw em into a video prog (or blender) & switch em over. quicktime should d/l the "authoring tools" (codec saver) if you don't have it already - seemed fairly straight forward to do. & sure I'd be glad to help if you want to pm

[Edited by - ProPuke on January 26, 2005 7:15:28 AM]

I already looked into QuickTime also, but guess what? DirectShow doesn't support QuickTime! It's like hitting my head on a brick wall! Thanks for the offer of help though mate, I'll be sure to drop you a line if I get stuck.

Kind regards.

Mark Coleman