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Alpha Channel Retarded
Hello I know that this must be something simple that I’m overlooking…
I have a client that wants me to give them QuickTime Files of a host that I’m going to key out from a green screen with the Alpha key in it so that they can import the files and right away read that alpha channel and put objects behind the subject.
While I have no problem keying in various programs such as After Effects, Motion, Final Cut etc. When I make a graphic in programs such as Live Type & Zaxwerk’s Pro Animator the QuickTime file that I bring in is automatically recognized and transparent around the text without me doing anything.
How can I create such a QuickTime file that is instantly recognized and makes everything transparent around my subject or such as this object?
When I attempt to create such a file and test it I can tell that it has an Alpha Channel but I cannot get programs such as After Effects & Final Cut Pro to automatically recognize it like if I made a QuickTime file in Live Type.
Thanks to any and all who spend time answering this question!
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6 Replies
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You need to tell the program to recognize. Only codecs with alpha channel capability work- like the Animation code, lossless or better an image sequence such as Photoshop.
Noah
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Two things.
If you’re using Apple’s recent interconnectivity and hot swap features (like importing a LiveType file directly into FCP rather than exporting a quicktime) and compositing graphics you’ve made in FCP, you have to remember that the production software bundle was designed to understand the specifics of each application’s project settings. For example, FCP and read motion’s project (it doesn’t just look at it as a quicktime movie), so it can tell where motion was assigning alpha values. This is very different from just importing a motion graphics with embedded alphas.
Second, Noah is right – of you’re just importing a graphic (motion or still) with an alpha, you have to tell your software that the alpha is there AND tell it what kind of compositing mode was used in creating this alpha this alpha (straight or premultiplied). Many packages will try to take a guess, but frequently the guess is not correct. Also, as Noah said, be sure you’re exporting your quicktime with an alpha-compatable. If including an alpha is a greyed out option in your export options, then your clip cannot have an embedded alpha.
Don’t forget that most video editing software allows you to composite fill and matte channels together, so you could always export separate fill and matte channels.
Best,
Ben
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Hi Guys, OK after 1 Hour of figuring this out, this is how you export a movie from Motion with Alpha Channel included, so when imported into FCP it is a transparent file, ready to superimpose.
1) Open your motion project file.
2) Go to Export and choose the following preset settings:
Kind: Quicktime ( Click Options and choose Animation )
Export Preset: Lossless + Alpha Movie
Include: Video Only ( If thats what you need)
Click box if you want to render only play rangeClick OK
Import into FCP, drag onto the top layer, and Voila it will be superimposed onto you under layers.
Thanks
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Or just drag the icon off the top bar, shift tab into FCP & drop
Peter
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Hi there can you clarify this a bit more in detail.
cheers
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Would you explain how to do this? Drag the icon into FCP, where is the icon?
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