How do you speed ramp in After Effects?

Enable Time Remapping on the layer (Ctrl+Alt+T / Cmd+Opt+T), add Time Remap keyframes where the speed should change, then ease them in the Graph Editor so the speed changes gradually instead of jumping.

What is a speed ramp?

A gradual change in a clip's playback speed, such as slowing into a moment and speeding back out, rather than a hard cut to slow motion.

Does a speed ramp make slow motion look smooth?

Only if the in-between frames are made well. In Premation, slowing down turns on Pixel Motion frame blending automatically, which estimates new frames with optical flow; fast or crossing motion can still smear.

Glossary

Speed ramp

Name: Premation
Author: Premation

A smooth change in a clip's playback speed: slowing into a moment and speeding back out, rather than a hard cut to slow motion.

Also called Speedramp, Speed ramping, Speed ramps, Ramped slow motion.

In After Effects

After Effects has no speed ramp command. You enable Time Remapping (Layer ▸ Time ▸ Enable Time Remapping, Ctrl+Alt+T / Cmd+Opt+T), add keyframes, and shape the Time Remap curve in the Graph Editor by hand.

In Premation

Animation ▸ Time ▸ Speed Ramp to 25%, with 50%, 200% and freeze ramps in the command palette. Each is written as two exact keyframes on an editable time-remap curve. Slowing down turns on frame blending.

Step by step

Select a video layer, an audio layer or a pre-comp and park the playhead where the slow-down should start.
Choose Animation ▸ Time ▸ Speed Ramp to 25%, or type "ramp" in the command palette. The clip eases into quarter speed over half a second.
For 50%, 200% or a ramp to a freeze frame, use the matching ramp command in the command palette.
Move to where normal speed should return and run Ramp back to 100%. The second ramp starts from the current speed, so it never snaps.
Open the graph editor (Shift F3) to reshape the ramp. It is two keyframes on a time-remap curve that you can drag like any other.

Tips

Ramp around the moment, not through it: slow down just before the action peaks and speed up after it, so the slow part lands on the interesting frames.
Slow motion needs frames to come from somewhere. Footage shot at a high frame rate ramps cleanly; 25 or 30 fps footage relies on frame blending to fill the gaps.
A ramp retimes the footage, not your animation: keyframes on the layer's position, scale or effects keep their own timing.
Ramp to a freeze, hold, then ramp back out for the classic freeze-frame promo beat.

Walkthrough: Speed ramp and slow motion video

Read the docs: Speed ramps

Questions

How do you speed ramp in After Effects?: Enable Time Remapping on the layer (Ctrl+Alt+T / Cmd+Opt+T), add Time Remap keyframes where the speed should change, then ease them in the Graph Editor so the speed changes gradually instead of jumping.
What is a speed ramp?: A gradual change in a clip's playback speed, such as slowing into a moment and speeding back out, rather than a hard cut to slow motion.
Does a speed ramp make slow motion look smooth?: Only if the in-between frames are made well. In Premation, slowing down turns on Pixel Motion frame blending automatically, which estimates new frames with optical flow; fast or crossing motion can still smear.

Related terms

Keep exploring

Try it in PremationFree · AGPL-3.0-only · macOS & Windows