I have used Premiere for many things over the years, but I recently tried to create an animation that relied heavily on animating the linear scaling of consecutive images, and so far I have been unable to achieve smooth linear scaling.
As an example(1), if I put 2 images on 2 seperate layers and scale each image from 1-100% over 10 seconds they will scale properly and in sync with one another.
But if I use five 2-second images, I find it is impossible to create a linear scale animation that stays properly in sync with example(1).
I stumbled on this when trying to create an "infinite zoom" animation where each image is a 2x scale of the previous image. The theory is you place these images sequentially on the timeline and animate the scale of each image from 50-100% (to create a continuous zoom). It is important when making this type of animation to have "linear" interpolation (and to make sure you don't have any duplicate frames at the image transitions). I very carefully set this up, but the rendered result was not the smooth linear continuous scaling I hoped for. Instead, the rendered result shows the scaling slowing-down slightly over the course of each image scale, so the final result appears to slow-down and speed-up with each image. If you look at this video, each image has about a 1.25 second duration, and you can visibly see the scaling surges every 1.25 seconds:
https://youtube.com/shorts/t9YYtvjdJLI
Using the effect control, I can step through each frame of the animation and Premiere reports a constant scaling rate of 1.3% per frame, but that is not reflected in the rendered result.
So I made another test where I scaled 2 bitmaps (red and blue) on 2 different layers. I also included a green box on the red bitmap which would reveal itself only if the scaling gets out of sync. At the beginning of the video you will see a version where each bitmap is scaled from 1-100% and everything syncs as expected - ie no green peeks (out indicating out-of-sync scaling). This is followed by a second example where I setup one of the bitmaps as 4 separate images on the timeline, with linear scaling on each:
https://youtube.com/shorts/aMKxdZgmYM0
On the second example you can see green peeking out around the edges of the red box indicating the scaling is out of sync. When I zoom in and watch carefully in Premiere I can see that the consecutive bitmaps are aligned at the transition points (where the keyframes are) but they get out-of-sync in the area in between.
The resulting videos give the impression there is easing going on, and that the nodes are not truly linear.
I would really LOVE to learn that I am doing something wrong, and that smooth linear scaling can be achieved with consecutive images. I encourage other users to create tests of your own and try to duplicate/dispel my results. I will list me Premiere and OS versions below.
Premiere version 23.5.0 (build 56)
Windows 10 Home
Version 10.0.19045 Build 19045
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