eli5: Why is rotoscoping (in video editing) so hard ? why can’t you just draw a new mask from scratch on every frame ?

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eli5: Why is rotoscoping (in video editing) so hard ? why can’t you just draw a new mask from scratch on every frame ?

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I mean, you could draw a new mask every frame…. But that’s even MORE difficult. That’s drawing 24 masks every second.

When rotoscoping, you set a mask with points, and every frame you drag those points to match the object you are rotoing. I think dragging points is way easier than drawing all the points again.

>why can’t you just draw a new mask from scratch on every frame ?

That’s the hard part!

How long does it take to draw a new mask each frame? Even at just a few minutes you’re in for a world of hurt trying to do it for even a short clip

Movies are generally 24 frames per second so a 2 minute scene where someone needs to be roto’d out of every frame would be 2,880 frames or 12 full work days (96 hours) at just 2 minutes per frame

Extend that to a 15 minute scene on a complex object that takes 5 minutes and you’re looking at 1,800 hours, or a bit under a full year of work

Rotoscoping in video editing is a time consuming process so a lot of the focus is on software that can do it quickly and good enough because for major productions there simply isn’t enough time to rotoscope everything by hand