Time-based media refers to media whose content unfolds over time, such as video and sound. In the provided context, the key point is that video is treated not as a collection of still images, but as a three-dimensional form with a temporal axis, described as a Space-Time Volume or Video Cube. Ordinary video playback is explained as a highly limited sampling process that presents this volume one frame at a time, as cross-sections perpendicular to the time axis.
The context also shows that time-based media is closely tied to temporal synchronization and simultaneity. For example, a system is described that takes video as input and generates matching sound in real time, including both continuous ambient/background sounds and momentary events, with audio output synchronized to the timing of the visual event. In another passage, altering the temporal reference across different parts of a frame disrupts spatial perception and even affects the conditions under which sound can be perceived as a stable object.
In this usage, time-based media is not simply any medium that involves time, but a form in which temporal slicing, synchronization, continuity, and perceptual reference points are central to the work’s structure. This definition is limited to what can be supported by the provided passages and should not be read as a full general definition.