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FCP and Ribbitfilms- alpha channel?
Ok, I have researched but cant seem to figure out how to create a video with an alpha channel. I did the png or tiff and even animation with millions plus but no where can i see an option to create an alpha channel. I downloaded boxer footage from ribbitfilms.com and they have him with a green screeen behind him. After the download its pure black and only the boxer already keyed I guess. What steps must I take to be able to use this keyed footage and be able to lay a background to the boxer? Thanks in advance
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5 Replies
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Does the footage come with a matte? If so, in FCP put the clip in v3, put the matte in v2 and the background in v1. Set your composite mode of the clip in v3 to travel matte luma. Set the composite mode by control clicking the clip. Render and you are good to go.
Jeremy
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Thanks so much it did come with a matte and I didnt realize why. Do you always need to put the matte behind ur keyed footage?
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Not if the footage has an embedded alpha channel. Graphics created in & rendered out of after effects and other compositing apps using the animation codec with millions plus will have an alpha channel. Most stock footage houses these days include a matte if you intend to superimpose their footage. This might be becuase not all NLE’s & compositing apps do not accept alpha channels, but this is just a guess.
If you have a scene shot on green, use AE to key the green and render out the key with an alpha channel (animation, millions+) you will not need to render a separate matte for use in FCP.
Cheers
Jeremy
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Thanks guys, I kind of have 2 smaller questions. What is precomping or precomps someone mentioned this to me while keying or just in fcp talk, and also when you nest a sequence nesting is basically taking two sequences and putting them both into your browser or 1 sequence correct?
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Anyone know if this is right. The friend also said to me there is a way to do a quick render where you can view the footage but it doesnt take up near as much space as doing regular rendering?
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