This post was last modified: 2021-10-23, 23:06 by fwbnz.

I have a 300 image timelapse with two keyframes. First keyframe is cropped. Last Keyframe is cropped further and is rotated. The resulting timelapse looks normal when being played until it reaches around a quarter of the way through at which point the colour changes noticeably.

That shouldn't have anything to do with the crop.
I'd suggest tobredo the workflow from scratch and see if it happens again.
To do so, remove the sequence from lightroom am in LRT do metadata/initialize. Then start over.
There is some interesting tutorials that might help you under https://LRTimelapse.com/tutorial/expert
Especially the one about the Ken burns Crop animation and also #5 which might explain what you a tree experiencing.

Thanks for the suggestion. I have re-run this several times, each time removing one more step until I have arrived at the conclusion that it's the crop rotation that is causing the problem. I have also started from scratch several times. Tried to attach the timelapse video but it didn't attach.

So the crop rotation makes the color change?? That sounds really strange.
Did you watch my tutorial about animating the crop where I explain for example that the crop should always be a bit smaller then the frame in order to not auto scale when touching the edges? Generally I'd recommend to do Ken Burns animation in a video editor and not in Lightroom/LRT - but still, a change of color is quite impossible, if you only animate the crop.

I've used LRTimelapse to generate the sequence of images which I have then exported from LR for rendering. When I look at the sequence of 300 jpg's that LR has written out, they all look good, but when they are rendered into an mp4 then the colour changes. Here's the jpgs that were rendered and the resulting video. https://1drv.ms/u/s!AnWwQMlxgkLxht0PU-mO...w?e=MNTdmz

Ok, thanks for sending the intermediary sequence.
I was able to reproduce that - it's the old problem, that Lightroom crops to full pixels when doing crop animations (as opposed to video programs, that do that much better).
In your case from frame 57 to 58 you have a change in image size from 6144x4096 to 6144x4097 - this is what confuses the video encoder and leads to that issue.
Didn't you get a warning in Lightroom when you rendered about possibly different image sizes/aspect ratios? I guess you might have ignored that.
I can only repeat my recommendation: export your video without any crop animation or even without crop at all. Then do such kind of animation later when assembling a film in a video editing program. The rotation will also be much smoother there.

Another advantage would be that you would apply the motion blur effect to the unanimated sequence (visually much more subtile) and not on the rotating sequence, which might blur the rotation and not only the scene itself.

Is the problem for LRTimelapse caused by the change in aspect ratio, or by the change in size?

This post was last modified: 2021-10-27, 10:53 by Gunther.

It's not LRTimelapse that has a problem with that, it's the encoder. I thonk it's the change in aspect ratio that causes the issue, unfortunately you cannot really prevent lightroom from doing that.

Hmmm... I did another timelapse where the size of the images varied (as per a Ken Burns effect) but the aspect ratio (square) stayed absolutely the same. I still got the colour shift. Is there a better/different encoder that might not cause these problems?

This post was last modified: 2021-10-30, 10:58 by Gunther.

How can that be? Only if you export with a fixed size in LRTExport (not source resolution). In that case lightroom will scale all exported images to the same size. If there was no aspect ratio variation then (which you cannot be totally sure of), it would be exactly the same size. And you wouldn't get the problems.

Apart from some jitter, that is immanent when cropping to fill pixels like lightroom does.

But again: that's all things that I'm pointing out as limitation doing Ken burns with Lightroom since years.

The technical issues occur if you feed images with different sizes to a video encoder. No vídeo encoder expects this.
And you cannot totally prevent it if you do Ken burns with Lightroom.

So please take my advice as I say it since the beginning: do those animations in video post processing when you cut and assemble your final film.