To set up a global time warping effect in your scene, you create a time warp curve.
To create a scene timewarp curve
A timewarp curve is added to your scene. The curve is automatically set to the same length as the playback range you specify in the Time Slider.
By default, the timewarp curve has two keys, one at the start time of the playback range, and one at the end time of the playback range. The Pre and Post Infinity options are set to Linear.
Once you’ve added a timewarp curve to the scene, you can edit the curve to create the timewarping effect you want.