How to Use Time Remapping in After Effects

Time remapping is a powerful feature in Adobe After Effects that gives you complete control over the playback speed, direction, and timing of a video layer. This guide covers how to enable Time Remapping, use keyframes to accelerate, decelerate, or reverse footage, and utilize the Graph Editor to create smooth speed ramps for cinematic results.

Enabling Time Remapping

  1. Import your video clip into your composition.
  2. Select the layer in the timeline.
  3. Right-click the layer, navigate to Time, and select Enable Time Remapping (or press Ctrl + Alt + T on Windows / Cmd + Option + T on macOS).

Once enabled, After Effects adds a Time Remap property to the layer with two default keyframes: one at the very beginning of the clip and one at the very end.

Basic Speed Adjustments

The distance between Time Remap keyframes dictates playback speed:

  • Fast Motion: Move keyframes closer together. The footage will cover the same amount of time in fewer frames, speeding up playback.
  • Slow Motion: Move keyframes farther apart. The footage will take longer to reach the destination time, slowing down playback.
  • Freeze Frame: Create two consecutive keyframes with the exact same time value. The playhead will hold that specific frame for the duration between them.
  • Reverse Motion: Swap the positions of two keyframes. If a keyframe with a higher time value appears before a keyframe with a lower value, the clip plays backward.

Creating Speed Ramps

To transition smoothly between different speeds (such as moving from normal speed to slow motion and back):

  1. Scrub to the point where the speed change should begin and click the Add/Remove Keyframe icon next to the Time Remap property.
  2. Scrub to where the speed change should end and add another keyframe.
  3. Adjust the distance between these keyframes to set your desired speed.
  4. Select all Time Remap keyframes and press F9 (or right-click and choose Keyframe Assistant > Easy Ease) to smooth the transitions.

Fine-Tuning in the Graph Editor

For precise, professional speed curves, use the Graph Editor:

  1. Select the Time Remap property and click the Graph Editor icon above the timeline.
  2. Ensure you are viewing the Speed Graph (click the graph options icon at the bottom and choose Edit Speed Graph).
  3. Select the keyframe points on the graph to reveal their bezier handles.
  4. Drag the handles horizontally to smooth out the speed curve. A steep peak represents high speed, while a flat line near zero represents slow motion or a freeze frame.

Enabling Frame Blending for Slow Motion

Slowing down footage below its native frame rate can cause stuttering. To smooth it out:

  1. Locate the Frame Blending column in your timeline switches.
  2. Click the icon for your layer once to enable Frame Mix, or click twice to enable Pixel Motion (Optical Flow).
  3. Ensure the master Enable Frame Blending button is toggled on at the top of the timeline panel.

Pixel Motion analyzes surrounding pixels to synthesize new frames, resulting in clean, fluid slow motion.