Choose the spacing
Set a tempo first, then choose a subdivision. 1/1 is one marker per beat. 1/2, 1/4, and 1/8 divide each beat into two, four, or eight parts. Bar writes one marker per bar using Time Signature.
At 120 BPM, 1/1 gives half-second spacing and 1/2 gives quarter-second spacing. At 4/4, Bar gives two-second spacing. The full subdivision table includes every option.
Place the grid in time
- Open the composition where you want markers.
- Choose Range in Settings. The default is Work area.
- Set First Beat. With the default At the playhead, place the playhead on a beat before laying the grid.
- Use Nudge (ms) if the whole rhythm needs to move slightly earlier or later.
- Click Lay grid, or hold the pad still for about half a second.
The anchor sets the rhythm’s phase. BPM fills the chosen range both before and after that anchor. The range start is included when a beat lands there; the range end is excluded. Marker times follow the tempo and can fall between composition frames.
On the first detected onset uses the first detected attack at or after the range start, falling back to the first detected attack if none follows that start. Run detection first or you will see Detect first.
Downbeats use comments such as bpm 1 and bpm 2. Bar numbering starts with the first downbeat written in the range. Other beats use bpm. Use Number the bars and Downbeat Color to control those labels.
Put markers on a layer
Select one unlocked layer and Shift-click Lay grid. Its label changes to On layer while hovered with Shift. The layer can be any type, not just audio.
If several layers are selected, BPM uses the first unlocked layer in After Effects’ selection list. Select only one for a predictable target. The range still comes from the work area or full comp, rather than the layer’s visible span.
No selection means no layer was selected. A locked-only selection reports Selected layers are locked. Unlock the target or choose another layer.
Mark individual sound attacks
Detect the audio, then Cmd-click Lay grid on macOS or Ctrl-click it on Windows. The hovered button reads Peaks.
This writes comp markers at detected onset times inside the chosen range. These are uneven sound attacks, not a constant beat grid. Peaks ignore subdivision, First Beat, Nudge (ms), and bar numbering. You can use those markers with the editing buttons too.
Replace or clear an old grid
Laying markers replaces all BPM markers on the chosen target, including old ones outside the new range. It does not remove BPM markers from other targets. Changing a setting alone leaves existing markers in place.
Alt-click Lay grid to use Clear. Clear removes BPM markers from the composition and every unlocked layer in it, including unselected layers and markers outside the work area. Locked layers are skipped. It does not require a tempo.
BPM recognizes markers by comments exactly matching bpm or bpm followed by a space and digits. Keep those names for markers you want BPM to use. Renaming a marker to something else removes it from BPM’s grid and cleanup.
Markers with other comments are kept. If a new beat lands at exactly the same time as one of your markers, BPM keeps your marker and skips that beat, and the toast tells you how many it kept.
Use Edit > Undo to reverse a grid change or Clear. None here means no removable BPM markers were found; the message also reports any locked layers skipped.