A horizontal rubberband that controls the speed of the clip appears across the center of the clip. The clip is shaded in contrasting colors above and below the 100% speed demarcation. A white speed control track appears in the upper portion of the clip, just below the clip title bar.
.
appear
in the speed-control track, indicating the section of the clip playing
in reverse.
To create a segment that plays in reverse and doesn't
return to forward playback, use the Razor tool to remove the segment
of the clip with the forward playback section, or remove it with
the Trim tool.
A gray area appears between the halves of the speed keyframe, indicating the length of the speed transition. The rubberband forms a ramp between the two halves, indicating a gradual change in speed occurring between them. A blue curve control appears in the gray area.

The change of speed eases in or eases out according to the curvature of the speed ramp.
