Enhanced Television is a collection of specifications developed under the OpenCable

OpenCable

OpenCable is a set of hardware and software specifications under development in the United States by CableLabs to "define the next-generation digital consumer device" for the cable television industry...

 project of CableLabs

CableLabs

Founded in 1988 by cable television operating companies, Cable Television Laboratories, Inc. is a not-for-profit research and development consortium that has cable operators as its members. System operators from around the world are eligible to be members. Members dues are based on revenue...

 (Cable Television Laboratories, Inc.) that define an ETV Application consisting of resources (files) adhering to the Enhanced TV Binary Interchange Format

Enhanced TV Binary Interchange Format

Enhanced TV Binary Interchange Format is a multimedia content format defined by a specification developed under the OpenCable project of CableLabs...

 (EBIF) content format as well as:

• PNG images
• JPEG
  JPEG
  In computing, JPEG . The degree of compression can be adjusted, allowing a selectable tradeoff between storage size and image quality. JPEG typically achieves 10:1 compression with little perceptible loss in image quality....
  
   images
• PFR downloadable fonts

An ETV application is normally delivered through an MPEG transport stream and accompanies an MPEG program containing video and audio elementary stream

Elementary stream

An elementary stream as defined by MPEG communication protocol is usually the output of an audio or video encoder. ES contains only one kind of data, e.g. audio, video or closed caption. An elementary stream is often referred to as "elementary", "data", "audio", or "video" bitstreams or streams...

s.

ETV Application

An ETV Application is a collection of resources (files) that include one or more EBIF resources that represent viewable information in the form of pages.

Two forms of a given ETV Application may be distinguished: (1) an interchange form and (2) an execution form. The interchange form of an ETV Application consists of the resources (files) that represent the compiled application prior to its actual execution by an ETV User Agent. The execution form of an ETV Application consists of the stored, and possibly mutated forms of these resources while being decoded, presented, and executed by an ETV User Agent.

ETV User Agent

An ETV User Agent is a software component that operates on a set-top box, a television, or any other computing environment capable of receiving, decoding, presenting, and processing an ETV Application. This component usually provides, along with its host hardware environment, one or more mechanisms for an end-user to navigate and interact with the multimedia content represented by ETV Applications.