Non-linear editing of text-based screencasts

Abstract

Screencasts, where recordings of a computer screen are broadcast to a large audience on the web, are becoming popular as an online educational tool. To provide rich interactions with the text within screencasts, there are emerging platforms that support text-based screencasts by recording every character insertion and deletion from the creator and reconstructing its playback on the viewer's screen. However, these platforms lack support for non-linear editing of screencasts, which involves manipulating a sequence of text editing operations. Since text editing operations are tightly coupled in sequence, modifying an arbitrary part of the sequence often creates ambiguity that yields multiple possible results that require user's choice for resolution. We present an editing tool with a nonlinear editing algorithm for text-based screencasts. The tool allows users to edit any arbitrary part of a text-based screencast while preserving the overall consistency of the screencast. In an exploratory user study, all subjects successfully carried out a variety of screencast editing tasks using our prototype screencast editor.