The studio
Preview & playback
Glass, grades and stacked effects are expensive. The preview remembers what it already drew, so you pay for a picture once — not every time you touch something.
The cache
Open it from the cache button at the left of the timeline toolbar. A bar above the ruler shows which stretch of time is ready to play instantly.
Keep: Layers remembers each top-level layer or group, so editing one rebuilds only that one — the right choice while you work. Keep: Frames remembers whole finished frames: the fastest replay, but any edit rebuilds the frames it touches. Use it for a final review pass.
A picture is kept only when it is exact for its instant, and it stays valid until something that affects it changes. Panning, zooming or selecting never throws it away.
Real-time or every frame
With Real-time playback on, AtomCut plays at speed and keeps what it can draw in time. Turn it off and it makes every frame before showing it — slower the first time through, then smooth.
Rolling cachedecides what happens when memory is full: let go of what’s furthest behind the playhead, or keep what you have and stop adding.
Footage
Decoded footage keeps video frames for instant scrubbing, reverse playback and filmstrips. Footage in layers also keeps layers made from video — glass over footage, a graded clip — for scrubbing and pausing. Leave it off for the smoothest playback while footage rolls.
Preview quality
The quality menu on the stage renders the preview at Full, ½, ¼ or ⅛ resolution. Auto picks the sharpest one that plays in time and still fits in the cache. Quality affects the preview only — exports render at the size you export.