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Masking/ Matting person from background
I have locked down video (a few slight camera shakes) of an interviewee that I’m trying to separate from the background so that I can insert a new background. No green screen.
I imagine this is pretty simple, but can you walk me through the process of creating a matte or mask of the interviewee, or is there a tutorial on this you can point me to?
I imagine this has something to do with isolating the luminance/color/black levels of the person and then transforming that into a mask above the original video layer on the timeline, but I’ve never done that.
Many thanks.
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7 Replies
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[John LeBlanc] “I imagine this has something to do with isolating the luminance/color/black levels of the person and then transforming that into a mask above the original video layer on the timeline, but I’ve never done that. “
Exactly, this is why you need a uniform background (color, luma) to be able to isolate the foreground.
If the background is not uniform the only way to do it is masking and rotoscoping.
Best,
Rafael -
[John LeBlanc] “I have locked down video (a few slight camera shakes) of an interviewee that I’m trying to separate from the background so that I can i”
The camera being locked down is good.
Is there a frame in your video that does not contain the interviewee?
If you do you can do a difference matte.
https://www.fcptips.com/final-cut-pro/difference-mattes-video_714208160.html
There are no “technical solutions” to your “artistic problems”.
Don’t let technology get in the way of your creativity! -
Hi Zane,
I was about to suggest that but John says that the camera shakes now and then.
rafael -
Well we haven’t actualy seen his footage so we don’t know for sure. He also did not mention if the background is moving. He may be able to edit around the camera shake.
There are no “technical solutions” to your “artistic problems”.
Don’t let technology get in the way of your creativity! -
He could use the stabilizer on it first, then maybe extract a clean plate frame to try the difference matte.
He could try copying the footage to another track, and radically changing the brightness and contrast settings until he generates something he can use as the basis of a mask.
Something I have tried, sometimes with success, sometimes not, is to export the video using quicktime conversion, creating sequential stills. You save those to one folder, take that folder into Photoshop, and use the “extract” tool as a fast(er) way to rotoscope. You Can set up a batch action in photoshop that opens each new frame in extract mode automatically, then saves it as TIF OR TGA and opens the next one. When you’ve processed all of these stills as tiff files with the alpha channel preserved, you have something you can layer back into a timeline like it was a chromakey… Set your import controls in FCp to give each imported still a one-frame duration, and import the whole folder, it should line back up from where you originally exported it like a mirror twin. It is not perfect, edge quality depends on your tablet or mouse skills, but by softening the edges a bit in the composite, it may do the job for you when nothing else will.
Look for “extract” in the photoshop filters. It walks you thru three steps: you trace a green line along the edge you want cut, straddling the part of their clothing/flesh/hair and the rest of the background. Second step, it asks you to eyedropper red into the inside of the matte. Then it shows you the result in a preview and asks if you like it or not. Little tools on the side pallette let you erase or put back bits of edge details by rubbing along. Very neat.
I am able to do one frame of this every 15 seconds or so. You might help the process work cleaner by adding some automatic actions to the batch action like adjusting the contrast and color-correcting, before the “extract” step.
Essential roto supplies:
Wacom tablet
Fully charged iPod
Too much soda.
Muted phone. -
I am going to use your method for a lot of footage, so its time to buy a stylus/tablet. could you recommend the most affordable and effective brand and model that’ll help this project go by quicker/smoother?
thank you!
a -
There used to be several competing brands but the waacom intuos pretty much owns the market now, it seems. Get the largest tablet you can afford. You can do the job with the smallest model, but it gets easier as the tablet gets larger.
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