HbbTV Building Blocks.

OIPF.

JavaScript APIs for TV environment (e.g. tuning, now/next info, PVR, …).
Media formats.
Modifications to CE-HTML.

CEA.

JavaScript APIs for on-demand media.
Subset of W3C specifications & image formats.
Remote control support (e.g. key events, spatial navigation).

DVB.

Application signaling.
Application transport via DVB (DSM-CC object carousel).
Stream events.

W3C.

XHTML.
CSS 2.1, CSS-TV.
DOM-2 (including XML Document support).
ECMAScript.
XMLHTTPRequest.