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Participant
Aug 20, 2024 5:22 PM UTC
Answered

Roto brush tool speed of rendering

I’m using After Effects on my ROG Strix G15 with 16GB of RAM, intel core i7, GTX 1650ti and Windows 11. When I try to remove a background from a three-second video and click ‘Freeze,’ the rendering process involves around 6000 frames, which takes a long time.

Steps to Encounter the Bug:

1. I import a three-second video into After Effects.
2. I select the area of the video from which I want to remove the background.
3. I click on ‘Freeze’ to start the background removal process.


The program should render a reasonable number of frames, like my brother’s laptop, which only processes around 170 frames, making the rendering quicker.

What Actually Happened:
The program is rendering approximately 6000 frames, leading to much longer processing times.

 

How can I reduce amount of frames that my laptop needs to render?

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Paul UuCorrect answer
Community Manager
Aug 20, 2024 5:49 PM UTC

Your clip appears to be 3 minutes long, not 3 seconds long.

Try trimming its duration in the Footage Panel to just the portion you wish to use.

https://helpx.adobe.com/after-effects/using/footage-items.html

8 replies

Participant
Aug 20, 2024 9:31 PM UTC

You are right. It was rendering 3 min raw video, not just the part I needed. Thank you!

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Warren Heaton
Community Expert
Community Expert
Aug 20, 2024 5:49 PM UTC

That is strange.

What is the frame rate of the 3-second source video?

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Participant
Aug 21, 2024 9:27 AM UTC

FPS 30

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Community Expert
Aug 20, 2024 5:49 PM UTC

I'm not clear why you're doing a freeze but you can have the monitor in focus and type "B" and "N" to compress the work area and to create a freeze based on a few frames. You can still stretch out the frozen layer in your timeline if needed.

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Paul UuCommunity ManagerCorrect answer
Community Manager
Aug 20, 2024 5:49 PM UTC

Your clip appears to be 3 minutes long, not 3 seconds long.

Try trimming its duration in the Footage Panel to just the portion you wish to use.

https://helpx.adobe.com/after-effects/using/footage-items.html

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Participant
Aug 21, 2024 6:53 AM UTC

 

I was trying to use Roto brush to remove background from 3 seconds part of whole video but when I tried to double click on my 3 seconds clip nothing happened and new layer where I can use roto brush wasn't crated like it was in tutorials on YouTube. Double clicking on whole video (3 min) worked indeed. 
I know I can trim exact part from this whole raw video, but it will take a lot of time every time just to find part you need.

 

so do you have any suggestions how I can remove background just from this 3 seconds part? 

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Warren Heaton
Community Expert
Community Expert
Aug 21, 2024 2:18 PM UTC

@Ivanna36328144cud7 

Try double-clocking while the Selection Tool is still selected.  Then switch to the Roto Brush Tool after the Layer Panel is open.

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