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Separated Alpha Channel
Is there a way to set a media as the alpha of another media? Not in a particular clip in the timeline but for all the duration of the media so that it uses that information whenever a clip with that media appears in the timeline.
Did i made myself clear? English is not my native language, obviously…
Any help is greatly apreciated.Thanks!
Francisco.
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9 Replies
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I think you will need to be a bit more specific with what you are trying to accomplish before anyone can offer suggestions. Your English seems fine, just elaborate on what you’re trying to do.
Andrew Lenczycki
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Ok, thanks for the sugestion, you’re right.
I’ll explain the hole story. I’m working in Vegas in a low budget tv series that involves a lot of chroma keying. Not surprisingly, we recieved some very hard to work whith blueish backgrounds that we now have to remove. Obviously we first tried to key them inside Vegas with the BCC chroma plug-in and a chocker for the edges. We have been fighting against this method for days now and cannot pull acceptable chroma keys from it. So, as I’m well accuented with AE, I suggested we should just use Keylight (which i consider the closest thing to magic i’ve ever seen). First attempts look promesing but my BOSS doesn’t want to invest in the amount of disk space the method of doing all the chromas in AE and export them in Quicktime PNG+Alpha would requiere.
To this point, the only thing I could think of to reccomend him was to do the keying in AE and render only the alpha channel in something like a good Quicktime H.264, thus reducing the disk space needed, and using that inside of Vegas to compose the final result.
I know what you’re thinking, seems like unnecesary trouble since disck space it’s cheap, but my BOSS it’s cheaper, so that’s that.
Now, i’m open to any advice (except to keep trying inside Vegas, it’s been days, i don’t want no more Vegas keying please!), but here are some thing that just won’t be usefull in our workflow: just doing the keying of the clips we use, corrections come and go and things get moved arround easily and many hands are involved, we need the full shot of the chroma ready for whoever whant’s to use a region or change it for another; and, for the same reason, we can’t compose the chroma in AE, it has multiple layers, there are graphics layers whith in and outs between the shot and the inserted backgruond.
So, in the method i had planned would be ideal to be able to just tell Vegas “hey, this file right here defines the alpha of that other file” not just in a clip, but in the media file itself. I can’t figure out a way to do this and the options i could think of are pretty time consuming and have a high risk of someone messing this up…
PLEASE HELP!
THANKS!Francisco.
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[Francisco Alvarez Raineri] “To this point, the only thing I could think of to reccomend him was to do the keying in AE and render only the alpha channel in something like a good Quicktime H.264, thus reducing the disk space needed, and using that inside of Vegas to compose the final result.”
In AE all you have to do is pull up the Output Module Settings in the Render Queue and use the following settings for QuickTime output using the Animation codec:
Change the Channels to Alpha and the Depth to 256 Grays and AE will output only the alpha channel as a black and white mask. You can then use this in Vegas Pro on a track above your video that is using the compositing mode Multiply (Mask) and it will mask just like the chroma key would have. The Animation codec should give you enough lossless compression to keep the file size small and the quality high.
~jr
http://www.johnrofrano.com
http://www.vasst.com -
Thank you very much for the 256 grays and codec information, they’re very usefull. Now, for the multiply (mask) in Vegas part, we tried that and it just doens’t work properly for us. It seems to really multiply insted of masking, this means the pure whites work as they should, leting the layer underneath visible, but not the blacks and the gray areas, where the multiplication results un greys and blacks. Allow me to demonstrate:
I made a simple shape in AE, and export it exactly as you told me:
Then I took it and set up a simple timeline in Vegas, and this was the result:
So, what i want this to do is to show me the green screen below the red sreen isted of the blackness of the top layer.
Of course, at this point i’m blaming Vegas for cheating and putting a multiply as the mask option, which are not the same thing… Is there anything i’m doing wrong?
THANKS!Francisco.
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[Francisco Alvarez Raineri] ” Is there anything i’m doing wrong?”
Yea, I forgot to tell you to add the Sony Mask Generator plug-in to the mask event. That will make the black show the background track. (sorry)
~jr
http://www.johnrofrano.com
http://www.vasst.com -
Yeah, we also tryied that but cuoldn’t get it to work just as the luma trackmatte does in AE… Anyway, we’re back to a full Vegas aproach, any suggestion on that?
Having said that, i’m very graetfull for the support given.So, THANKS!
Francisco.
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[Francisco Alvarez Raineri] “Yeah, we also tryied that but cuoldn’t get it to work just as the luma trackmatte does in AE”
What doesn’t work about it because I know this works. How is it different in AE than in Vegas Pro? Maybe we can figure out why it’s not working for you.
~jr
http://www.johnrofrano.com
http://www.vasst.com -
I double checked, it turns out i was using a bcc plug-in for that last part and not the Vegas one.
To sum up, it works(!!!), so now lets just hope the BOSS lets me do the f**** chromas in AE…
No amount of thank yous could describe my gratitude. So i’ll just writte one: THANK YOU!P.d.: now I oficialy hate a little less Sony Vegas and a lot more the Boris plug-ins…
Francisco.
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[Francisco Alvarez Raineri] “To sum up, it works(!!!)”
Awesome! You’re welcome. Glad I could help.
~jr
http://www.johnrofrano.com
http://www.vasst.com
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