Timeline
Retime layers, set in and out points, and add comp or layer markers in After Effects through Prism — frame-accurate timing you can pair with beat markers for music sync.
Timing is where motion design lives or dies, and it is also the most tedious thing to nudge by hand. Prism lets you describe timing in plain language — "hold this layer until the second beat," "trim the intro to 24 frames," "drop a marker every chorus" — and writes the result onto your real timeline as native, editable values. Nothing is approximated: the AI reads your live composition first, so it works from the actual frame rate, durations, and existing markers rather than a guess.
How timing requests work
Every timeline change runs through Prism's read → reason → write loop: the AI inspects the active comp, plans against its true state, then writes values you could have typed yourself.
Because timing is resolved against the comp's real frame rate, "half a second" becomes an exact frame count, and "the last frame" means the last frame — not a rounded approximation.
Retiming layers
Ask Prism to move, trim, slip (shift which part of a layer's source plays without moving the layer), or stagger layers and it rewrites their timing in place. Common requests:
- Shift a layer earlier or later by a set amount.
- Stagger a stack of layers by a fixed offset so they cascade.
- Trim a layer to a target duration without re-positioning its content.
- Compress or spread out an existing sequence to fit a new length.
The layers themselves stay native — same source, same effects, same keyframes — only their position on the timeline changes.
In and out points
Setting in and out points is frame-accurate. You can state timing in seconds, frames, or relative terms ("end on the comp's last frame," "start where the title leaves"), and Prism converts to exact frames for the active comp.
Ask for timing in whatever unit is natural. Prism resolves it to frames against the comp's real frame rate before writing anything.
Comp and layer markers
Markers are first-class. Prism can add them at the composition level (on the timeline ruler) or on individual layers, with labels and comments, at any frame you specify.
| Marker type | Lives on | Good for |
|---|---|---|
| Composition marker | The comp timeline | Section cues, review notes, sync points shared across layers |
| Layer marker | A single layer | Per-element timing, expression-driven triggers, local cues |
Because you describe positions in plain language, "a marker at each scene change" or "label these three cues intro / build / drop" becomes a clean, evenly placed set rather than hand-dragged guesses.
Pairing with beat markers
Prism's audio tools detect BPM and beats in a music track and drop them onto the timeline as markers (see audio and beat sync). Once those markers exist, the timeline tools work against them: snap a layer's in point to the nearest beat, stagger entrances across consecutive beats, or trim a sequence so it lands on the drop. Detection and timing are separate steps, which keeps each one accurate — the beats are real, and the layers move to meet them.
A worked example
| You say | Prism does |
|---|---|
| "Trim the intro to 24 frames, then stagger the three lower-thirds by 6 frames each and drop a marker labelled Drop at 4 seconds" | Sets the intro's out point to frame 24, offsets each lower-third by 6 frames so they cascade, and adds a comp marker labelled Drop at the exact frame for 4 seconds |
What you get back: native in/out points and markers at exact frames, resolved against the comp's real frame rate — fully editable and undoable in one step.
If timing has no frame to resolve to: ask to set timing in a comp that isn't open and Prism says it has no active comp rather than writing to the wrong place — open the comp first, then ask again.
Notes and limits
- Every timeline change is reversible in one step — see how Prism works.
- A few timeline operations are occasionally intermittent in After Effects itself; if one doesn't take, re-run it once or see troubleshooting.
Related
- Build a rhythm grid for your timing with beat markers.
- Animate property timing with keyframes, not scripts.
- The active comp is the context — see compositions.
- Haven't set up a client yet? Connect your AI.
Expressions
How Prism writes working After Effects expressions — inertial bounce, wiggle, loops — while animation comes back as editable keyframes by default.
JSON pipeline
Serialize an After Effects comp or project to structured JSON, let your AI read and rewrite the whole structure, then import it back as real, editable layers.