ADOBE AFTER EFFECTS: Forum Expressions Tutorials Creative Cloud

Time Remapping messes with masks

COW Forums : Adobe After Effects

<< PREVIOUS   •   FAQ   •   VIEW ALL   •   PRINT   •   NEXT >>
Matthew Beall
Time Remapping messes with masks
on Sep 23, 2016 at 4:03:03 pm

I have several animated masks on footage that is precomposed.
When I time-remap the pre-comp, the timing of the masks is now off.
Do I need to render the pre-comp first?


Return to posts index

Roei Tzoref
Re: Time Remapping messes with masks
on Sep 23, 2016 at 4:32:08 pm
Last Edited By Roei Tzoref on Sep 23, 2016 at 5:41:35 pm

if the masks are inside the precomp (as where they should probably be), in the pre-comp go to composition settings and advanced and tick this:



Roei Tzoref
After Effects Artist & Instructor
♫ Ae Blues Tutorials


Return to posts index

Walter Soyka
Re: Time Remapping messes with masks
on Sep 23, 2016 at 4:45:34 pm

Are your masks animated inside the precomp, or on the precomp layer itself (as a peer of the time remapping)? It should be the former.

Walter Soyka
Designer & Mad Scientist at Keen Live [link]
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
@keenlive [twitter]   |   RenderBreak [blog]   |   Profile [LinkedIn]


Return to posts index


Matthew Beall
Re: Time Remapping messes with masks
on Sep 23, 2016 at 6:38:44 pm

Checking 'preserve frame rate' seems to have fixed it!

Thank you



Return to posts index

Roei Tzoref
Re: Time Remapping messes with masks
on Sep 23, 2016 at 6:47:17 pm
Last Edited By Roei Tzoref on Sep 23, 2016 at 6:50:39 pm

Great! thanks for the feedback. BTW this is because you time remapped native ae time with video. Ae creates intermediate frames to fill the in betweens as long as it's native Ae movement (keyframes on still, effects, text, vectors, really anything but an image sequence or Video)- but for video it cannot really blend time in the same way. Walter Soyka - a little help here rephrasing this properly ? :)

Roei Tzoref
After Effects Artist & Instructor
♫ Ae Blues Tutorials


Return to posts index

Walter Soyka
Re: Time Remapping messes with masks
on Sep 23, 2016 at 7:16:52 pm
Last Edited By Walter Soyka on Sep 23, 2016 at 7:26:55 pm

[Roei Tzoref] "Ae creates intermediate frames to fill the in betweens as long as it's native Ae movement (keyframes on still, effects, text, vectors, really anything but an image sequence or Video)- but for video it cannot really blend time in the same way. Walter Soyka - a little help here rephrasing this properly ? :)"

There are are three frame blending options in Ae for when you are retiming footage (or using footage in a comp with a different frame rate): Off, Frame Mixing, and Pixel Motion.

When frame blending is off, Ae skips or repeats frames as necessary to play back the source footage in the comp. There are no synthesized frames, and the motion can be stuttery and uneven.

When frame blending is set to frame mix, Ae creates new intermediate frames by blending the two real frames together, weighted according to time. There are new frames created here, but it's a very naive method, simply mixing existing frames. This can sometimes be very smooth, but other times unnatural.

When frame blending is set to pixel motion, Ae attempts to measure the change in location of every pixel from one frame to the next (motion estimation), then synthesizes new entirely frames by interpolating each and every pixel along those vectors it calculated between the real frames. This can look very convincing in some cases, but can get "gloopy" when the true motion vectors are unclear (such as the case of a foreground crossing a background in opposite directions).

Walter Soyka
Designer & Mad Scientist at Keen Live [link]
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
@keenlive [twitter]   |   RenderBreak [blog]   |   Profile [LinkedIn]


Return to posts index


Roei Tzoref
Re: Time Remapping messes with masks
on Sep 23, 2016 at 7:37:19 pm

Thanks Walter. yes you can manipulate video, but for the creation of the frame Ae has to pull some tricks, really only one trick that truly worth the time (ha!) and that's pixel motion and if you got a few motion vectors you can forget about it... for layers and keyframes he doesn't. this what I meant - how do you explain, or where is a resource for explaining the fact that there is a difference between time remapping a precomp with or without footage. I have trouble phrasing it... for example in Matthew's case there are some masks roto or what not, and he want's to speed it up - this will create inconsistency between Ae native mask layers + keyframes and the footage unless he checks the preserve frame rate.

Roei Tzoref
After Effects Artist & Instructor
♫ Ae Blues Tutorials


Return to posts index

Walter Soyka
Re: Time Remapping messes with masks
on Sep 26, 2016 at 10:43:52 am

[Roei Tzoref] "- how do you explain, or where is a resource for explaining the fact that there is a difference between time remapping a precomp with or without footage"

Ah, now I understand. I wouldn't phrase it exactly this way; time-remapping works the same on comps whether they have footage or not, but footage responds different to time-remapping than the animated properties of layers do.

Footage, by definition, is locked to a specific frame rate. When we apply time remapping to footage, we only have information for the frames of the original footage at its original frame rate, so any time we stretch or compress footage in time such that the original footage's frames do not line up with the comp's frames, we have to make up what we think the new frame might look like. My previous post covered different methods for doing this.

Animated properties in Ae are not locked to any specific frame rate. In fact, when Ae is calculating the in-between values between two keyframes (this tweening is called interpolation), it works in time expressed in seconds with decimal points, not any kind of frame count. This means that any time-remapping here can remain completely fluid: we can slow down an animation with no motion footage 1,000x or more, and it will remain perfectly smooth. Because frames don't really exist for these properties, it's no problem to work with extreme sub-frame precision.

However, as this example shows, that smoothness is not always desirable. Here, your masks could animate smoothly (because they are native properties of Ae) but your footage could not (because it is subject to its original timing). The checkbox that Roei describes forces Ae to treat these properties at the timing of the comp, instead of as the infinitely smooth math they could be.

Have I clarified or confused the issue? Any questions?

Walter Soyka
Designer & Mad Scientist at Keen Live [link]
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
@keenlive [twitter]   |   RenderBreak [blog]   |   Profile [LinkedIn]


Return to posts index

Roei Tzoref
Re: Time Remapping messes with masks
on Sep 26, 2016 at 12:40:55 pm

Thanks Walter that's helped. how about this:

time remapping to native properties in Ae is infinitely smooth because keyframes are not locked to frames or frame rate. when you manipulate time for a precomp with only native properties you can get smooth results every time.

time remapping to footage is limited because the data is locked to the frames and frame rate. when you manipulate time you can only get smooth results if creating new frames works perfectly (the frame blending option of pixel motion) otherwise it will duplicate or remove frames and the movement will not be smooth.

sometimes you have both footage and Native layers with animated properites and in the same timeremapped precomp, and in this case you should try 2 options:
1. set you footage to pixel motion and see if it's stretches smoothly with according to native properties of layers
2. set the smoothness of both to off by checking the "preserve frame rate when nested" checkbox in the nested precomp's composition settings.

Roei Tzoref
After Effects Artist & Instructor
♫ Ae Blues Tutorials


Return to posts index

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
© 2017 CreativeCOW.net All Rights Reserved
[TOP]