Join Chris Meyer for an in-depth discussion in this video Frame blending options, part of Premiere Pro and After Effects: Adding Handle to Sound Bites.
So we've time remapped our video inside After Effects, but since I've stretched these frames to last over a longer duration of time, I'm getting some visual stuttering caused by the repeated frames, particularly here at the end where I'm really trying to stretch out just a few frames of source material. Well, the way to solve that in After Effects is to use something called Frame Blending. Frame Blending needs to be enabled in two places in After Effects. One, you need to turn on the switch for the layer and one click get's you what's called Frame Mix Mode for Frame Blending.
And you also need to turn on Previewing a Frame Blending for the composition. As it is right now, this will still render with frame blending, but if you want to see this in your comp panel, you need to turn on that switch in the timeline panel as well. Now, let's run a preview of this and see how it looks. It'll take just a couple moments to calculate, but it is slower than normal video. There's been other improvements to After Effects in this October 2013 release. There's been other improvements to After Effects in this October 2013 release. So it's no longer stuttering.
It is indeed just slower, and a little bit better of a mix, but it does seem to go in and out of focus. That's because in between frames of source, After Effects is mixing together multiple frames as source material. Therefore, I like to use an advanced mode in After Effects called pixel motion mode. To do that, you go to the frame blending switch for your layer, and click on it a second time to get a solid rather than a dashed line. This will use a different algorithm. You may have heard it referred to as optical flow, which actually creates brand new frames of source material for every interpolated frame in your playback.
You'll notice that this ghosting in my teeth has disappeared now. There's two problems with pixel motion mode. One is that if there's a lot of motion in the shot, it can cause undesired artifacts. Now in this relatively simple shot, with just my head moving a little bit, there's no artifacts. But don't just turn to some blindly and assume it looks good. Always preview the result to see if there's any tearing going on particularly when you've got one object moving and another object stationary in a frame. But here it works pretty well.
The other problem with pixel motion mode is that it's slow. It takes much longer to render. I'll just briefly hit the ramp preview here And you see how slow it is to render those frames. So if you're a real hurry, if you're really concerned about performance, what you can do is split the clip and not frame blend the source material that's supposed to be playing back at normal speed. This will save you computation time, it will also save you the possibility of frames being altered and getting a softened video. So I'm going to select that video layer and use Edit>Split Layer, the shortcut is Cmd on Mac, Ctrl on Windows, Shift+D, I got one split layer, and go to this other time remap key frame, and split it again.
This middle layer, which is the body of me talking, no longer needs frame blending, so I'll turn that off. However, for the tail handle and the head handle, I'm going to leave frame blending turned on. Now let's preview this and see how it looks. There's been other improvements to After Effects in this October 2013 release.
There's been other improvements to After Effects in this October 2013 release. That's a much more natural motion in the end. Now if you're not happy with how things look like particularly this very end frame here. There is two things to keep in mind. One, your very head and your very tail are going to be buried in cross fades in between the clip before and after informational graphics etc,. And I might even sometimes, just to re-assure myself, create a little opacity cross fade in After Effects just to make sure it's going to look okay. But the other thing to keep in mind is that you can change these Time Remap keyframes.
If you don't like that frame of source material, you can go ahead an edit the Time Remap keyframes. Let's make sure I'm editing the correct layer. I'll press, U to reveal my keyframe properties. In this case, Time Remap. Now I'm going to change, the value, for that last frame of source material to use one frame earlier in time and see that gives me maybe a little less disconcerting of movement. You know I'm going to use even one frame earlier than that. And my mouth is little bit more closed, my head isn't tilted quite as far back and see if I can get away with that.
This course was created and produced by Chris and Trish Meyer. We are honored to host this content in our library.