Composing sink

A WAI package of several components, each carried in the capability that suits it. This page checks the package's signed receipt and every object it is about to present, dispatches each component to a decoder this device can run, and composes them on one timeline with the video as its clock. Titles this device cannot draw are presented as text, from the transcript the package carries for them. A field, or a picture with layers, is computed here stage by stage, and each stage is presented once it holds its signed digest.

What this device dispatched, and why

Checks before presenting