Switched to Keylight in AE from Ultra Key in Premiere Pro but now render times are hours longer?

[jamesk45987928]

I have searched and read a lot, and it seems like slow render times are just par for the course in After Effects but I still feel like I'm missing something.

For previous videos I was simply using ultra key in Premiere Pro, nothing too fancy, just a video of me with some gameplay behind me (after the green-screen is keyed out). If the video was 7 minutes long, render times were roughly 10 minutes (at most).

My green screen and lighting isn't perfect though and I heard that you can get better keying in after effects, so I used the keylight preset (with spill sup and that other effect) but the render time for this 7 minute video is now 4-6 hours. It just doesn't seem right.

I tried both rendering just the video with the keylight effect by itself in encoder, using multiple different render formats and it was all pretty much the same for render time, I currently have the AE project imported into premiere pro, where I did the edits I needed to do, and rendering it through premiere pro with my normal settings (H.264, 1080p, 30fps, 16mbps bitrate) and it's 11% done with over 4 hours to go.

I double checked Cuda/GPU acceleration was on, my system specs are:

i7 4770k @ 4.2Ghz
16GB DDR3 RAM
GTX 1080
500gb Samsung 840 Evo SSD (this is the drive it's rendering to)

The source video (that keylight is being used on) is mp4 format with a fixed 30fps.

Is this normal, or have I messed something up?

[chrisbrearley · Accepted solution]

Completely expected. Premiere runs off of GPU and I'm guessing the new ultra keyer is completely GPU powered as well. After Effects and Keylight are archaic and have to rely on one cpu core.

[A.I.1]

To me hours of rendering for a 7 min video even with green screen does sound a lot though. I'm sure mine takes much less, though I've recently have better success with the Colour Range keyer and Spill Suppression effect instead of using Keylight and that (colour range+spill suppression) goes reasonably fast on my machine (minutes for a few mins of footage - though the most recent one wasn't full 1080p and was only 23.976 fps - though i still don't think it would be hours on my PC with 1080p30 unless there were lots of other effects etc. in the video).

edit: I've just done a test at 1920x1080p29.97 of a 35 sec 25 frame vid with Colour Range keyer and Advanced Spill Suppressor, VBR2 pass, 16 Mbps (for target and max) and that took 2 mins 18 secs to render.

[Mylenium]

Keylight always has been and still is a slow memory hog and buggy as hell. Especially the AE version is merely being "maintained" rather than being developed actively. If you need this regularly, it would be smart to buy a third-party keying plug-in like the BorisFX keyer for instance.

Mylenium