Adjusting roto brush in After Effects 2025

[Ygramul]

The source is a 15 second, 1920x1080@30fps static shot of someone sitting and talking. The playhead is on the first frame. I use roto brush to select the person and press "freeze" to analyze the footage. When it's done, I notice that there's just a few frames about halfway through that need some adjustments. Can I do something about that without having to wait for the whole thing to be re-analyzed? If I unfreeze the layer, AE just starts doing its thing again.

I saw a Youtube tutorial where someone made the selection in the first frame and then went frame by frame manually before freezing. Makes sense, I guess, although there's almost always something to correct after freezing anyway.

[Brainiac]

My workflow:
1. With playhead on the first frame, select whatever I need to rotoscope, then I make various adjustments in the Roto Brush & Refine Edge panel as needed.
2. Press the play button in the preview panel (or the spacebar) so that AE rotoscopes frame-by-frame automatically. If the rotoscope goes wonky, I go to that frame, make corrections, then I hit the play button (or spacebar) again so that AE makes the necessary corrections from that point forward.
3. After I get the rotoscoping correct THEN I hit the freeze button to lock down the matte to prevent recalculating.

You can unfreeze to make changes after freezing, then freeze again.

[Ygramul]

My workflow:
1. With playhead on the first frame, select whatever I need to rotoscope, then I make various adjustments in the Roto Brush & Refine Edge panel as needed.
2. Press the play button in the preview panel (or the spacebar) so that AE rotoscopes frame-by-frame automatically. If the rotoscope goes wonky, I go to that frame, make corrections, then I hit the play button (or spacebar) again so that AE makes the necessary corrections from that point forward.
3. After I get the rotoscoping correct THEN I hit the freeze button to lock down the matte to prevent recalculating.

You can unfreeze to make changes after freezing, then freeze again.

OK, I'll try that. I only play around with AE as a hobby, so RAM previews isn't something I use out of habit. What's the difference between a RAM preview and a roto brush freeze?

[Brainiac]

A ram preview renders and stores frames in memory for smooth playback.
Freezing locks down the matte so that AE does not recalculate it.