[Kalleheikki Kannisto]

Simplest solution is to animate the opacity of the text layer from 0 to 100 to 0 as it moves from top to bottom.

[Kalleheikki Kannisto]

Select all layers, press “T” for opacity and adjust the setting in one of the layers. All other layers will be adjusted the same.

[Kalleheikki Kannisto]

What version of Photoshop are you running? I find the CC2015 versions buggy on this aspect. For instance my InDesign simply quits when I try to print directly from it, so instead I make a PDF of the document first and print from Acrobat.

[Kalleheikki Kannisto]

Your original expression (fixing the “sw” to “n”) works fine for what you describe.

freq =effect("frequency")("Slider");
n = Math.sin(time*freq);
if (n<=0) 0 else 100

If you animate the slider the blinking will speed up or slow down, unless you are using hold keyframes (which keep a constant value until the next keyframe).

If you want another layer to blink differently, you can add something to the time value of the second line, for example

n = Math.sin(time*freq+100*index);

[Kalleheikki Kannisto]

Placing the frames on separate layers and using the Difference blending mode to blend them will also give the pixels that are different between the frames. You will likely have to add a Levels adjustment to emphasize the results.

That works as long as the camera is perfectly still. Even small camera shake between the frames will show up as edges. In such case you can get rid of the extra edges with the Minimax effect to a degree.

[Kalleheikki Kannisto]

Do the objects that pass in front cover the entire frame at some points? Such parts cannot be stabilized automatically. If so you’ll need to track such sections manually — or skip them if tracking the near object makes no difference.

If some part of the main scene is visible at all times, you can track different parts of the shot and parent the nulls together.

Here’s a method that handles a similar situation, a long pan where the part being tracked goes out of frame and you have to pick another point to keep going:

https://library.creativecow.net/articles/kramer_andrew/Set_Extensions.php

The difference being that the tracked point gets obscured rather than goes out of frame, so you would pick another point and keep going.

[Kalleheikki Kannisto]

My two cents. Stabilize the second shot, track the first, apply tracking data to a null and attach the second shot to that null. Result: unified motion.

[Kalleheikki Kannisto]

The spawning of the leaves is done by animating the scale from 0 to (something).

I don’t know how the animation was actually done. I’m saying that it looks like it might have been done that way (motion sketch).

There are many ways of creating this type of animation, most of them more realistic than the example, and most of which require a plug-in of some sort to accomplish. Particular and Element 3D have been mentioned, both of which would make the particles move in 3D and could be controlled with some master controls, not requiring each individual leaf to be animated.

Even in “plain” After Effects, you could make the leaves 3D layers and make it look way more realistic.

But the leaves in the sample video are clearly not rotating in 3D. They are only moving and scaling. Which is why I was suggesting the relatively easy option of using motion sketch. The other options are more advanced: for instance, expressions could be used to create the motion of the individual leaves so that you wouldn’t have to animate each by hand. But coming up with the expressions would likely take as long or longer than animating them by hand.

[Kalleheikki Kannisto]

Bit hard to say what is causing that without seeing anything other than the result.

Probably simplest to scale the path to match the original. Double-click the path with the selection (arrow) tool to select all points and press Ctrl-T (PC) for free transform and scale the path up using the bounding box handles while holding the shift key to constrain proportions.

[Kalleheikki Kannisto]

You definitely got a problem of some sort or another.

Have you tried shooting in any other format?