This class represents the richmediainstance dictionary. This is definitively detailed in:.

The ISO PDF Specification, ISO 32000-2:2017 PDF 2.0; Table: 343, page 706.

Adobe Supplement to the ISO 32000, BaseVersion: 1.7, ExtensionLevel: 3; Table: 9.51b, page 89.

This class is always an indirect object because D3DNodeElement.EntryInstance, RichMediaConfigElement.EntryInstances, RichMediaExecuteActionElement.EntryTI and ViewParamsElement.EntryInstance require it to be so.

System.Object
    WebSupergoo.ABCpdf14.Elements.Element
       WebSupergoo.ABCpdf14.Elements.RichMediaInstanceElement

A rich media instance dictionary references a single media asset and its playback parameters within a configuration. The Subtype entry identifies the media kind (3D, Flash, Sound, or Video). The Asset entry holds the file specification. The Params entry holds type-specific playback settings.