Background removal not going as planned...

[SidedTech]

So I'm just learning how to use after effects and a lot of the tutorials have been fantastic and I've been able to get around pretty well. 

When issue I have is that when I'm removing the background using the roto tool sometimes the green bar will dissipate from the beginning of the video as if I didn't do that part yet. Like it's following me through the video as I clean up each section, and then I have to go back do that part again..

First time I did it I dragged the slider all the way right after applying the initial roto brush, that covered the whole video, and then I was able to click through and see different frames that were missing proper background removal or were causing clipping. I was able to then find that part and fix it.

Sometimes now when I'm working a lot of the time when I go back to fix it the green bar that shows that the roto brush has covered the entire area from beginning to end shrinks as if I didn't do a certain part or as if I'm messing something up after dragging the slide all the way to the end. 

If anyone knows what I'm talking about thank you 😅

[Mylenium]

Without any system info, details about your project and source footage, screenshots and al lthat this isn't telling us anything. You need to be much more precise and provide soem actual info.

Mylenium

[SidedTech]

Using the roto brush creates a green line across the software saying that I've covered the entire video and then somehow that green bar starts to shrink from the left side.

If I was any more specific than that I have no idea how that would be possible. 

My system is a 5900X AMD with a 3080 video card and an MSI motherboard with 32 gigs of DDR4 ram. 

If you know the green bar that is created under the video when using the roto brush to show that the roto brush has covered that area, then you wouldn't need a screenshot but I could probably make a video and upload it to streamable.

I'm just trying to figure out why it would cover portions of the video that I already did and then start to delete itself as I move the cursor to the other parts of the video. 

To give you an idea of what I'm doing I'm importing the video. Then I use the roto brush to remove the background behind the person. I then drag the cursor all the way to the right to do it for the whole video. This creates a green bar. I then go back through the video to see if it missed any portions which it always does, and somehow it erases portions that it already did such as ones at the end of the video and beginning of the video that we're fine after I fix the parts in the middle. 

[Rick Gerard]

Rotobrush requires you to watch the propagation and add new strokes to include or remove different parts of the background as the tool analyzes the footage. Make a change at 3 seconds, and that change must propagate through the entire clip. Refine an edge and that modification must also propagate. Rotobrush is not a click-once-and-walk-away tool. The more similarity there is between the background and the foreground, the more you have to babysit the tool. Only after Rotobrush has been frozen can you fiddle with the other controls in the Effects Control Panel to do more cleanup on the edges. I don't see any buggy behavior or anything unexpected in your description of your workflow. 

[SidedTech]

How exactly do I freeze the roto brush because that seems to be what I'm asking for and I didn't say it was a one click anything but I do want to know how to freeze it because that's what I'm having issues with. 

[Kyle Hamrick]

Once you've created at least one stroke with the Roto Brush, you should see this "Freeze" button at the bottom of your viewer. 

[SidedTech]

Awesome, thank you, I just used it, and it seems to have helped me get halfway through the issue. I am going to watch the official Adobe video on this again because I learned this from there, and I think I missed something LOL