After Effects Gotchas

Color

After Effects and Premiere interpret color differently for some, but not all, footage types – so if you throw a LUT on a clip via Lumetri and then apply all the same settings in both applications, to the same clip, the color might be different. I figured this out when doing a quick and dirty color correct, thought my footage was borked, and then looked at it in Premiere – where it looked… fine.

After Effects can be stupid slow using Lumetri. In general, Premiere’s version of Lumetri is superior and you won’t take any significant performance hit. It’s just a bummer because color correcting in-comp is a superior work flow for VFX. 

Performance

After Effects can be really slow, but it is very good in telling you why it’s slow [in almost all ways]. In most cases, you can just wait, but if you’re rendering a lot of very big things, you can make a significant improvement to render speeds by doing a little composition tweaking. Maybe Fast Box Blur looks good enough instead of Lens Blur (it probably doesn’t, but you should check anyway). 

Your first thing should be to always purge the memory and disk cache. Once you’ve filled up the cache, After Effects functions like a complete idiot. After Effects does not remind you that your cache is full, you have to remember to do this when performance begins to drag. 

To analyze why else your composition is taking so long to render, you can really dig through the program. 

At the very bottom of the timeline is a little button called “Expand or Collapse the Render Time pane.” This toggle will show you down to the sub-settings of an effect why your rendering is taking so long. 

In the image above, it’s telling me that “another layer” is taking 880ms per frame to render. Of that, 724ms are effects. Of that, 699ms is Lumetri, and 25ms is CC tiler. The very bottom tells me the Frame Render Time is 886ms. In this example, the other layers only represent 6ms per frame to render. What this tells me is that Lumetri is quite slow in this scenario. Can I use a different effect stack to speed it up and reach the same image goals? Is it faster to pre-process the color in another application?