Rate Stretch
Rate Stretch lets you change a clip’s playback speed by dragging its edge. Make a clip longer and it plays slower. Make it shorter and it plays faster. The edit point stays anchored and the content stretches to fill the new duration.
How to use it
Section titled “How to use it”Press R to activate the Rate Stretch tool. The cursor changes to indicate rate stretch mode.
Hover over a clip edge — left or right. Drag:
- Drag right edge rightward → clip gets longer → plays slower
- Drag right edge leftward → clip gets shorter → plays faster
- Drag left edge leftward → clip gets longer from the beginning → plays slower
- Drag left edge rightward → clip gets shorter from the beginning → plays faster
The opposite edge stays anchored. Only the edge you’re dragging changes.
What Rate Stretch does in After Effects
Section titled “What Rate Stretch does in After Effects”Rate Stretch adjusts the AE layer’s Stretch property.
- 100% stretch = normal speed
- 200% stretch = half speed (twice as long)
- 50% stretch = double speed (half as long)
This is AE’s native time-stretch feature, not time remapping. The entire clip plays uniformly at the new speed — there’s no curve, no variation, just a constant speed change.
Context menu — Speed/Duration…
Section titled “Context menu — Speed/Duration…”Right-click any clip → Speed/Duration… to enter an exact speed percentage or duration. This is the dialog-based version of rate stretch. You can type in 50% for double speed, or type in a specific duration and let Railcut calculate the speed.
The dialog shows the current speed percentage and duration. Change either one and the other updates accordingly.
Time remapping vs. Rate Stretch
Section titled “Time remapping vs. Rate Stretch”| Rate Stretch | Time Remapping | |
|---|---|---|
| Where | Railcut clip edge drag / Speed dialog | AE’s native time remapping (Layer → Enable Time Remapping) |
| Effect | Uniform speed change via layer Stretch | Variable speed via keyframe curve |
| Undo | Single undo step | Multiple keyframes to manage |
| Best for | Quick speed changes, fitting clips to durations | Speed ramps, freeze frames, reversed sections |
If you need a speed ramp or variable speed, don’t use Rate Stretch — use AE’s Time Remapping instead.
Limitations
Section titled “Limitations”- Rate Stretch is clamped to 10%–1000% speed (0.1× to 10× normal speed). Extremely slow or extremely fast stretches beyond this range are not supported.
- Rate Stretch applies uniformly. You can’t create a speed ramp from Railcut’s Rate Stretch tool.
- Some source types (precomps, shapes, text) can be stretched but the result may not look as expected, since they’re not time-based footage in the same way.
Snapping
Section titled “Snapping”When dragging with the Rate Stretch tool, snap is active. The clip edge snaps to nearby edit points, the playhead, and adjacent clip edges. This makes it easy to fit a clip to exactly the length you need.