How to Use Time Remapping in After Effects

A workflow taught by Adobe Certified Instructors at Adobe Video World.

Time remapping gives you complete control over the speed of a layer, letting you slow down, speed up, freeze, and reverse footage all within a single clip. It’s how editors create dramatic slow-motion moments and dynamic speed ramps. This guide explains how time remapping works and how to use it for smooth, professional results.

What Time Remapping Does

Time remapping lets you control a layer’s playback speed with keyframes, mapping any point in time to any frame of the footage. Unlike a simple speed change, it lets the speed vary across the clip — fast here, slow there, frozen elsewhere.

This means a single clip can start at normal speed, ramp into dramatic slow motion, and snap back, all driven by keyframes. That flexibility makes time remapping far more powerful than a fixed playback rate.

Enable Time Remapping

To turn it on, select your layer and choose Layer > Time > Enable Time Remapping. After Effects adds a Time Remap property with two keyframes — one at the start and one at the end — marking the first and last frames of the clip.

These keyframes are the handles you’ll manipulate. Each one represents a moment in the source footage, and by moving them in time you change how quickly the layer plays between them.

Slow Down and Speed Up

To slow a clip, drag the ending Time Remap keyframe further to the right, stretching the same footage over more time so it plays slower. To speed it up, drag that keyframe left, compressing the footage into less time.

Adding keyframes in the middle lets you vary speed within the clip — slow during a key moment, normal elsewhere. This selective control is the heart of time remapping and what separates it from a uniform speed adjustment.

Create a Freeze Frame

To freeze the action, set two Time Remap keyframes to the same frame value with a gap of time between them. Because the footage doesn’t advance between those identical keyframes, the image holds frozen for that duration.

You can then resume normal playback by adding another keyframe after the freeze. This freeze-and-resume technique is great for emphasizing a moment, then letting the action continue, all within one continuous clip.

Reverse Footage

Time remapping can play footage backward by arranging keyframes so time runs in reverse — a later keyframe pointing to an earlier frame. As the playhead advances, the footage rewinds, creating a reverse effect within the clip.

Combined with forward sections, you can make footage play forward, reverse, and forward again for rhythmic, looping motion. This keyframe-based reversing is more flexible than a simple reverse, letting you control exactly where it happens.

Build a Smooth Speed Ramp

The most cinematic use is the speed ramp — a gradual transition from normal speed into slow motion and back. Place Time Remap keyframes at the ramp points and apply Easy Ease, then refine the velocity graph so the speed change accelerates and decelerates smoothly.

Without easing, speed changes snap abruptly. Smoothing the keyframes in the graph editor, using the same approach as our keyframe guide, is what makes a ramp feel like a deliberate, professional move rather than a glitch.

Smooth Slow Motion with Frame Blending

Slowing footage below its native speed can make motion look choppy, because there aren’t enough real frames to fill the slower playback. Frame blending and especially Pixel Motion generate in-between frames to smooth the gaps.

Enable frame blending on the layer and choose Pixel Motion for the best results, which interpolates new frames by analyzing movement. For extreme slow motion, though, footage shot at a high frame rate always looks cleaner than any software interpolation.

Time Remapping vs. Time Stretch

After Effects also has Time Stretch, which changes a clip’s speed by a fixed percentage across the whole layer. It’s simpler but uniform — every part plays at the same altered speed, with no variation.

Use Time Stretch for a quick, constant speed change, and Time Remapping when you need speed to vary, freeze, or reverse within the clip. Knowing both means you reach for the simplest tool that does the job.

Time Remapping Best Practices

• Enable Time Remapping from Layer > Time before keyframing.
• Add middle keyframes to vary speed within a clip.
• Ease your keyframes for smooth speed ramps.
• Use Pixel Motion frame blending for cleaner slow motion.

Common Time Remapping Mistakes

• Linear keyframes that make speed changes snap abruptly.
• Slowing footage too far without frame blending, causing stutter.
• Using Time Remapping when a simple Time Stretch would do.
• Forgetting to enable it before trying to keyframe speed.

A Real Speed Ramp Example

Take a clip of a skater landing a trick. You let it play at full speed on the approach, then place Time Remap keyframes just before the landing and stretch them so the moment of impact drops into dramatic slow motion. After the landing, you ramp back to normal speed as they roll away.

Applying Easy Ease and smoothing the velocity graph makes the transitions glide rather than snap, and enabling Pixel Motion frame blending keeps the slow section fluid. The result is the cinematic speed ramp seen in action edits everywhere, all built from a few well-placed, well-eased keyframes on one clip.

Match Time Remapping to Music

Time remapping becomes especially powerful when synced to audio. Ramping a clip into slow motion right as a beat drops, or snapping it back to speed on a musical hit, ties the visuals to the rhythm and makes an edit feel intentional and energetic. The speed changes land where the ear expects emphasis.

Drop markers on your beats first, then place your Time Remap keyframes against them so the speed changes hit precisely. This rhythmic approach, combined with clean easing, is what gives music-driven edits their satisfying punch, turning a simple speed change into a deliberate creative beat.

When you need smoother slow motion than keyframed retiming provides, the Timewarp effect’s optical-flow frame generation fills the gaps.

Speed ramps timed precisely to the track are everywhere in music video editing.

Bending time with remapping is closely related to the Echo effect in After Effects, which overlays past and future frames into trails.

Key Takeaways

• Time remapping controls layer speed with keyframes.
• Slow, speed up, freeze, and reverse within one clip.
• Ease keyframes for smooth, cinematic speed ramps.
• Use Pixel Motion frame blending for clean slow motion.

Frequently Asked Questions

How do I use time remapping in After Effects?

Select your layer and choose Layer > Time > Enable Time Remapping, which adds a Time Remap property with start and end keyframes. Drag and add keyframes to control how fast the layer plays between them.

How do I make smooth slow motion?

Stretch the Time Remap keyframes to slow the clip, then enable frame blending with Pixel Motion to generate in-between frames. For extreme slow motion, footage shot at a high frame rate always looks cleaner.

What’s the difference between time remapping and time stretch?

Time Stretch changes speed by a fixed percentage across the whole layer. Time Remapping uses keyframes so speed can vary, freeze, or reverse within the clip. Use Time Stretch for constant changes, remapping for variable ones.

Sources: Adobe’s guide to time-stretching and time-remapping.