Changing speed and duration with time remapping
Time remapping lets you vary the speed of a clip by using keyframes. This means one portion of a clip could play in slow motion while another portion of the same clip plays in fast motion.
In addition to giving you flexibility, variable-speed time remapping enables you to smoothly transition from one speed to another, whether from fast to slow speed or from forward motion to reverse motion.
- In the Project panel, load the sequence 04 Remapping.
- Adjust the height of the Video 1 track by positioning the Selection tool over the split between audio and video tracks. Drag down to make more room to see the video tracks.
- Right-click the clip, and choose Show Clip Keyframes > Time Remapping > Speed.
- Drag the playhead on the Timeline to the point where the villain turns and starts walking across the room (about 00:00:10:00).
- Press and hold the Control (Windows) or Command (Mac OS) key as you hover your mouse over the white line.
- Click the white line to create a keyframe, visible at the top of the clip.
- Using the same technique, add another speed keyframe at about 00:00:17:00, just as the villain points to the wall.
- Leave the first section, between the beginning of the clip and the first keyframe, with a default Speed setting of 100%.
- Position the Selection tool over the white line between the first and second keyframes, and drag it down to approximately 30%.
- Choose Sequence > Render Effects in Work Area to render the clip for the smoothest playback.
- Play the clip. The speed changes from 100% to 30% and back to 100% at the end.
- Speed keyframes are actually in two halves. You can click and drag to separate them. Try it now: Drag the right half of the first speed keyframe to the right to create a speed transition ramp.
- Drag the left half of the second speed keyframe to create a transition there as well.
- Right-click the video clip, and choose Frame Blend. This smooths playback when changing the speed.
- Render and play the clip to see the effect.
The sequence has a single shot. As you add time adjustments to the clip, it will change length.
Increasing the track height makes adjusting keyframes on the clip right in the Timeline much easier.
With this option selected, the white line across the clip represents the playback speed.
The pointer changes to a small cross.
You’re not changing the speed yet; you’re just adding keyframes.
By adding those two speed keyframes, you’ve divided the clip into three “speed sections.” You will now set different speeds between keyframes.
The clip stretches in length to accommodate the speed change.
Setting variable speed changes on a clip can be a very dramatic effect. So far, you have created a speed change that switches from one speed to another instantly. That can be highly effects but it’s possible to transition from one speed to another smoothly adjusting the speed keyframes.
The white line ramps down now, rather than making a sudden change from 100% to 30%.