Alfa channel and green screening

S

s-audio

Active member
I think I already know the answer to this question but I thought maybe someone might know a trick or some kind of workaround to make this happen.

Is there a way to save out my green screened footage with a clear alpha channel. so that someone else could put media in the back ground?
I am working on a web based training project and they would like me to key out the green screen footage so they can add there animated back grounds and text.

I don't think it's possible but I thought I'd throw it out there. Any ideas??
 
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Certain codecs have alpha channels. Quicktime Animation is one which comes to mind which I've use with Adobe After Effects. I'm not sure if it's supported by Vegas but it shouldn't be hard to find out.
 
AVI and Quicktime .mov have alpha channel support in Vegas. Don't have Vegas on my Droid to look at settings, but search in video tab of render settings and you should see it. Glad to detail specic settings after I get back in office tomorrow. Sorry for any typos, still getting my big fingers used to typing on a little keyboard.
 
Thanks for the info Guy's. I'll look in the rendering setting for AVI and .MOV.
If it works it could save me from turning down a project.
 
I found a setting in the AVI uncompressed format.
Do I check the box that says render alpha channel?
 
Is this in the export settings? The problem with uncompressed AVI is that it creates extremely large files. Vegas doesn't support any Quicktime output formats?
 
I did not see an option for rending with the Alpha channel in Quicktime . I have quick time 6.
maybe it is available in a later version. I just have what came with Vegas.

I found the setting to render Alpha channel in the custom settings for uncompressed AVI.
I am not sure if I should un check the box so that the alpha channel does not get rendered
for use in another program or not.

I want to be able to render a file so that it still retains the alpha channel. No backround for use in another program.
 
Give it a try with a couple of seconds of test footage.

I was unaware that uncompressed AVI had an alpha option - but yes, I can see the option on the Render window, and the Help screen indicates it should work.
 
I tried uncompressed AVI with render alpha channel checked . I rendered a small portion of video and then put it on the time line. i put some generated media under it on another track and it did not show through.
I put it over the video on another track and it did show through either.

Then I rendered another uncompressed video with render alpha channel unchecked.
I tried the same steps as previous. No luck.....

I right clicked on the video and went to the media tab. And tried some of the alpha settings in there with no luck either.

Anyone know the secret to rendering with a transparent background? I'm Stuck.
 
As suggested above, try quicktime animation codec in .mov.

If you re-import into vegas, you need to right click and enable alpha. Other programs like AE will have no problems (should automatically interpret alpha)
 
Ok, I tried quick time with the animated setting . Rendered it and brought it back into Vegas.
Put it on the time line, selected the clip properties and tried each of these settings.
I also had some generated media on a track to see if it worked.
Still no go........

Alfa channel: undefined
Straight unmated
pre multipy and premultiply dirty
 
I figured it out!!
I think Vegas 6 has a bug. When I rendered a uncompressed AVI with the alpha channel checked off and put it on the time line, I then right clicked on the clip and selected Alpha source.
I could see the original AVI file in the media pool flash as if it was now updated also. But it still did not work.

Then I deleted the clip on the time line and right clicked on the AVI in the media pool and selected Alpha source then dragged the AVI from the media pool back on to the time line and it worked!

I had to do the same thing when I did a animated .MOV file. You have to select alpha source in the media pool not the time line....
This is weird stuff.

Thanks for everyone help I really appreciate it!
Ron.
 
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