Speed Transition in Adobe Premiere
After creating a speed change using time remapping, you can fine-tune the change to create a smoother transition between the different speeds.
When you create a speed keyframe, it has two handles joined together in the speed control tack. The example on the right shows a clip with an initial speed of 150%, reduced to 50% at the keyframe.
Drag either of these handles left or right to create a transition area, shown in gray. A blue curve control appears in the middle.
Drag either of the handles on the curve control to smooth the transition — the speed change will ease in and out.