This paper demonstrates how the “sharable dynamic media” concept seen in Webstrates can support complex, high-performance applications: video composition and editing. The authors propose a new substrate for representing video. It’s still DOM-based, like a normal webstrate, but a videostrate may contain many <video> tags, transitions (e.g. via CSS), procedurally generated video (e.g. via <canvas>) and effects (e.g. via WebGL).
A videostrate can be transcluded into a single <video> tag in a parent DOM tree. At present this is implemented by server-side rendering.
Because a videostrate is a webstrate, it inherits all the properties of sharable dynamic media: they’re inherently collaborative; many tools can act on the same document; users can make or customize tools on the fly; etc.
In a show of sprezzatura typical for this excellent group, the video associated with this paper was itself produced using the videostrates tools.