Abstract: A processing device can partition a video presentation into segments, wherein the beginning of each of the segments corresponds to when a specific subtitle would be displayed. In some examples, a system can be configured so that a subtitle in a selected language can be displayed at that point, even if subtitles in a different language are being displayed by default. A user can thus activate a rewind control for a video playback device or application and obtain a translation of the dialog at that point into the user's preferred language. The subtitle-based rewind feature can be implemented, as examples, in a client playback application on a playback device for streaming video, as part of a video streaming provider's back-end services deployed in a cloud network, or by a combination of the two.

Abstract: A coupling includes a driving disk connected to a driving shaft and rotatable about a driving axis. An engagement face of the driving disk includes a predetermined number of at least three driving teeth that are distributed azimuthally on the engagement face of the driving disk along a circle concentric to the driving axis. A driven disk connected to a driven shaft and rotatable about a driven axis has an engagement face including the predetermined number of driven teeth azimuthally distributed along a circle concentric to the driven axis. At least one of the driving shaft and the driven shaft possesses translational freedom or angular freedom of motion with respect to the other so that when the driving teeth of the driving disk engage the driven teeth, the driving axis and the driven axis are self-aligned.