The present disclosure includes systems and techniques relating to generating transitions for remapping video playback time. The subject matter described in this specification can be embodied in a method that includes providing a digital video editing user interface that includes a variable rate speed control configured to define associated keyframe elements including a begin element, an end element and an intermediate time element; receiving input defining at least one of the keyframe elements in relation to a sequence of digital video; and generating a time transition function for remapping playback time of the video based on the input, wherein the time transition function maintains predefined speed for video frames leading into the begin element, maintains predefined speed for video frames leading away from the end element, and changes video speed from a begin speed value to an end speed value in accordance with one or more intermediate time element values.