Beats
Prism detects BPM and beats in your audio and places frame-accurate timeline markers in After Effects, giving every animation a rhythm grid to land on.
After Effects has no native way to find the beat of a track. You either count frames by hand, tap markers live, or eyeball the waveform. Prism analyzes your audio for tempo and beats, then writes frame-accurate markers onto the timeline so every cut, scale pop, and keyframe has a rhythm grid to land on. The analysis runs server-side; what comes back into your project is a clean set of real composition markers you can use like any others.
Why beat markers matter
Motion that lands on the beat reads as intentional; motion that drifts off it reads as sloppy, even when the timing is close. The hard part has always been knowing exactly where the beats are. A marker on every beat turns that guesswork into a grid: you place keyframes against markers, and the whole sequence breathes with the music.
Prism builds that grid for you so you spend your time on the animation, not on counting frames between kicks.
How it works
Beat detection is one of Prism's tools. You point it at the audio in your project and ask for markers. Prism reads the track, estimates tempo (BPM), locates the beats, and converts each one to a precise time on your timeline — the same read, reason, write loop Prism uses for every action.
The analysis runs on Prism's server, so nothing is installed or built locally; the panel places the result in your timeline. Audio is sent only for the analysis, then discarded — your project stays on your machine. The markers are written as native objects, so they are fully editable and removable in a single undo step.
How to use it
Run it from the Tools tab, or ask your AI in plain language — Prism runs the same tool either way.
A worked example
| You say | Prism does |
|---|---|
| "Detect the beat of the music in this comp and drop a marker on every beat." | Reads the audio track, estimates the tempo, locates each beat, and writes a frame-accurate composition marker at every one. |
What you get back: a row of native composition markers across the timeline, one per beat — snap targets for your cuts and keyframes.
If the track has no clear pulse: detection may return "no steady beat found in the audio." That happens on sparse or free-time passages; try a section with a clear, steady pulse, or place those markers by hand.
Beat markers vs. doing it by hand
| Task | By hand | With Prism |
|---|---|---|
| Find the tempo | Tap along, estimate | Detected from the track |
| Place a marker per beat | Frame-by-frame, manual | Written automatically |
| Keep markers in sync | Re-do after any edit | Re-run the detection |
| Editability | Native markers | Native markers |
Beat detection is one of Prism's AI-native capabilities — things After Effects can't do on its own. Once the markers are on the timeline, building a beat-synced sequence is just keyframing against the grid.
Notes and limits
- Beat detection works best on tracks with a clear, steady pulse; sparse or rubato passages give looser results.
- If you edit the music or change its timing, re-run detection to refresh the markers.
- Beat markers are available wherever Prism runs: After Effects 2024, 2025, and 2026, on macOS and Windows.
- Beat detection spends 1 AI credit per analysis from your credit wallet. See usage and limits for plan caps and the full per-tool credit costs.
Related
- AI-native After Effects — the capabilities AE doesn't have on its own
- Animation and keyframes — animate against the marker grid
- Timeline & markers — snap in points and stagger entrances against the beat grid
- How Prism works — the read, reason, write loop behind every tool
- Usage and limits — credit costs and plan caps