Alpha help please!!!!!!!!

RogerB wrote on 1/10/2003, 6:56 AM

I really want to buy Video Factory, but I wont unless I can get this Alpha feature working like I want. I have the Demo and have spent much trial and error as well as online research, and I am not sure if it just doesn't work, or the feature is disabled in the Demo.

I am putting a video in the video layer. In the overlay layer, I put a video that is to be a title that displays and I want to see the video layer underneath where there is not text. I made the title video in the overlay layer using Flash. It is just some animated black text and the background is white.

In the properties of my overlay video, I change the Alpha from none to Premultipled. Whatever that means, I have tried them all: strait, premultiplied dirty etc. I then click the background color box and using the dropper or RGB values to select the background of the overlay title video which is white. Then I have tried setting the "Alpha" value to 0, 255, and numbers in between. To no avail, I cannot get this to work.

Am I doing this wrong, or do I need to buy something like Premiere for this capability.
Thanks for detailed info.

Comments

Former user wrote on 1/10/2003, 8:32 AM

Are you sure the Flash file is carrying the Alpha channel?

The only way to carry an AVI with an Alpha channel is to make an uncompressed AVI. I don't know about Flash, but if there is not an alpha channel, it will not work.

Dave T2

RogerB wrote on 1/10/2003, 10:50 AM

I am not sure if it has the alpha channel with it when I brought it in, but I thought that was the purpose of the eye dropper in Video Factory to select the color that I want to be my Alpha color. Is this called Chroma Keying?

Former user wrote on 1/10/2003, 11:52 AM

What you are trying to do would be similar to chroma key, which Video Factory does not have.

You would need Vegas Video for that function.

If you did not expressly build an alpha channel, then it probably doesn't have one.

Dave T2

RogerB wrote on 1/10/2003, 1:11 PM

I see, although I could not get it to work in the demo of Vegas Video that I downloaded. What then are the eyedropper/RGB settings for in Video Factory's Alpha property. It clearly is letting you define something.

Former user wrote on 1/10/2003, 1:17 PM

That is probably letting you define the color of the alpha channel, but since you don't have one, it has no effect.

Dave T2

RogerB wrote on 1/11/2003, 11:21 AM

Could you please email me a small video less than 1 meg (I have 56k dialup) that has an alpha so I could try this. Thanks

JohnnyRoy wrote on 1/11/2003, 2:06 PM

> ...so I could try this.

VideoFactory box version comes with a content CD that has effects videos on it like explosions with alpha channels and it works just fine. Just drop one on the overlay track and there’s a big Hollywood style explosion with your video playing in the background. So VF supports overlaying video with alpha channels.

You can create your own video with alpha channels to try it out. Go to Ulead’s web site and download the 30 day trial copy of Cool 3D Studio and make yourself a spectacular 3D rotating title (‘cuz its real easy with this tool). Then use File->Export Video Overlay->AVI. This will render an AVI file with the background as an alpha channel. It will take a long time to render but Ulead is working on a patch for this. (i.e., it takes longer than it should so keep it short)

Now drop that AVI on the overlay track and you should have a spinning title over your video. You can also create a still graphic with Photoshop, or Pain Shop Pro, or Real-DRAW Pro, or whatever your favorite graphic editor is and add an alpha channel and save as TGA or PNG (which support alpha channels) and you’ll get a nice title overlay.

You can even drop an animated GIF file that has alpha transparency and it will play like a video with the background showing through. I found an animated GIF of a bat for Halloween that flew in a circle. I dropped it on the overlay track, stretched it out to loop a couple of times, and used Pan and Crop to make it start out big and end up small. I then dropped a video of the moon on the video track under it and it looked like the bat was flying up to the moon. So there are lots of places you can get files to try out the alpha overlay.

Hope this helps,

~jr