Hi All-

I’ve been using LRTimelapse 5.2.2 with a Private license for quite some time now. I’ve rendered many videos, but I’ve run into an issue on a couple recent time lapses which has me a bit stumped.

I’ve recently rendered a couple timelapses that include a lot of cloud movement and there are a few moments of noticeable pixelation/artifacts in the video. I’ve rendered plenty in the past without this problem. The odd thing is no matter how many times I try re-rendering, it’s always in the same place.
I’ve searched the forums and found the closest post to my issue here:
https://forum.lrtimelapse.com/Thread-wei...ing-to-lr5

I’ve been on LRtimelapse 5 for some time, but I’ve only seen this issue recently. I can’t recall exactly when I upgraded to 5.2.2, but I certainly never saw the issue before now, so there may be some relation with the upgrade

I’ve uploaded a couple clips to youtube to share what I’m referring to.

4 seconds in to this clip you’ll see the pixelation in the clouds on the left hand side.
https://www.youtube.com/watch?v=yMNSXVvR...e=youtu.be

The second clip in the above link starts at 8 seconds and you can see a fair amount of pixelation in the clouds on the right hand side.

I’ve gone through a bit of troubleshooting, trial and error, and different render options.
I noticed that I did not see any pixelation in the “render preview”, nor do I see it if I render it at 1080p, or even 3k
If I render at either of the 4K options, I see this behavior.

Here is a 1080p rendered version of the first clip from above, and there is no pixelation at all:
https://www.youtube.com/watch?v=0ioWxFNk-yA

System Specs:
2019 27inch Imac Retina 5k
3.7GHz Intel Core i5
24 GB Memory
Radeon Pro 580x 8GB


My workflow
Source images: 6000x4000px RAW taken from a Sony a6000
Exported from lightroom using the LRT JPG 4k option in Lightroom
Rendered in LR Time-lapse with:
4K UHD
24 fps
Quality: High (i’ve also tried ultra high)
Color Sampling: 420
Gamut: Standard (BT 709)
LRT Motion Blur 3 (i’ve also tried it without)
Sharpen: On

I’d like to be able to export this in 4K, so If anyone has any ideas to try, or possible explanations for the behavior I’m seeing, I’d really appreciate it.

As explained in the faq, If you render 4k in 3:2 aspect ratio, you exceed the MP4 specification, which may cause problems. LRTimelapse also gives you a warning about that.
Either check - force 16:9 when rendering or use a better codec, like prores, which doesn't have such limitations.