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more efficient way to mask?
I have a short video clip of a guy handing something over a counter that has very minimal movement. I’ve created a mask on the clip and am using a jpg with a different background in the layer underneath it to make it look like he’s standing in that background.
Because there’s very little movement, I changed the mask’s shape every 3 – 5 frames, and it looks pretty good, though there’s some clean-up that needs to be done on the mask in various frames to make it look seamless, and I’m wondering if there’s a more efficient way to handle the work flow of changing the mask every couple frames, rather than doing it manually, as I am.
Thanks for any help-
Ruby -
13 Replies
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Best way is to make multiple, simple- shaped masks that are animated as whole shapes as often as possible (rather than animating individual mask points). Also, try to use as few keyframes as possible- every 10 frames is usually a good place to be, though sometimes you have no choice but to do frame by frame. The more you do this, the faster (and smarter) you get at it.
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Well, how many masks are you using.
Can you break up parts into separate masks like:
1. for his legs
2. torso
3. arms
4. neck
5. head
6. hands.if you mask with muliple objects you only have to move certain parts at a time and then it’s easier to handle fixes without screwing everything else up too.
good luck.
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our posts are 1 minute apart. well said mstieger.
cheers
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Indeed.
I’d add that you should study the movement (over and over) first, then place keyframes at places where the direction of motion changes, whether that motion is shape or position. Another way to look at it is: animated mask vertices move from location to location at each keyframe, and AE interpolates the location of each mask vertex between those keyframes. If you place the vertices carefully, AE will interpolate in such a way as to follow the motion of the masked object.
It’s much more efficient than choosing to place keyframes at a specific frame interval, since most roto’ed motion doesn’t work on a regular time interval.
Watch the motion, then set keys according to that motion.
Steve
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Thanks you guys!! Really useful suggestions. This forum rocks.
Ruby -
Here’s my opinion on the roto thing and after lots of practice:
1. Yes, if it’s a complex shape, break it up into parts: Head, torso, arm, etc..
2. First get a track from the main parts. For example, the head. Do a track on something in the person’s face, like a glint off the nose or whatever. Apply this data to a null. call the null, “head track”.
3. on the main video layer, go to the first frame and draw a mask around the guy’s head. Cut this matte and paste it onto a new solid. Turn on keyframing on ‘mask shape’ parameter. Use this solid layer as an alpha matte on the main footage layer. So your mask is still masking the video layer from another track. Now parent the mask/solid layer to the “head track null” assuming the track was good, your mask will travel with the head. But by time you get to the last frame in the clip the shape is off in shape only. On the last frame, reshape your mask – a key will be made. Now go to the very middle of the clip. The mask shape should be extremely close to being good because the tracker put it in the right place and the beginning and end keyframes on the shape should make it interpolate to a decent approximation. But it probably is off a little. so reshape it a touch to fit the head. Now if you need more reshaping, always split other keyframes in the middle. This way AE can do the interpolation for you. So find two keys and go half way between them. Also make sure the keys going down are not linear but auto. Nothing in nature other than machines move linearly. you’ll find that if you have auto bezier that your interpolation will often match up better to real life.
Chris Smith
https://www.sugarfilmproduction.com -
This sounds great, though over my head (experience-wise). I’ve not tracked anything before and the whole null/parent thing is something I’ll have to spend some time with–but thanks for the directions to follow once I get there.
Ruby
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One thing that has really sped up my roto lately is to do my roto on a layer which has the little eyeball turned off, and then to lock all other layers. That way you never lose your ram preview so your frames always update instantaneously. It has cut my roto time at least in half. Some functionality for choosing points is limited in this mode, by the way (you must choose multiple points individually, the marquee box for choosing multiple points won’t work).
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Could you explain a bit more? I brought a single video layer in to test your theory and when I turned off the little eye button, my layer dissapeared? And I thus couldn’t see the outline I was trying to mask?
Thanks -
Yes, the layer disappears but you should still see the mask outline if you have the layer selected. This definitely speeds up workflow if all you need to see is the mask outline and the BG layer.
I have a question about bezier mask handles in AE and I don’t know if I should start a new thread on this or not. Rotoscoping is tedious enough, but is anyone else annoyed at AE’s bug where the tangency of the bezier handles break apart for absolutely no reason. I then have to undo the move, hold down CTRL and move the handle again. Now they are tangent. But it happens over and over and over. And randomly. Anyone have a better workaround for this? I’m using AE 6.5 Professional and I would have though Adobe would have fixed this glitch by now. Thanks.
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