tru2way - Interactive Services over US Cable Systems
Interactive TV
usually means the viewer using the remote control to "interact" with the TV
to change the presentation of video, audio or on-screen graphics in some way.
These changes are typically made by an interactive software application running
in the set-top-box or TV. The purpose of this process is to enhance the
viewer's experience by possibly showing additional information (the local
weather whilst watching the Weather Channel), voting during a news
program or purchasing an item during a favourite TV show related to that show.
tru2way is a standard for writing and delivering to the home interactive TV applications specifically for the US cable market.
Tru2way is the consumer brand for a technology known as
OCAP
which stands for the
"OpenCable Application Platform".
It is based on a programming language designed by Sun Microsystems called
Java.
Tru2way applications are delivered to home by encoding these Java programs into the digital TV signal. Digital TV is compressed using a format called MPEG and tru2way is transmitted in an object carousel encoded with the MPEG audio and video packets.
The screen shot to the right is an example of a tru2way application designed by Starz Entertainment, LLC. This application is a bound application, in that it runs on a particular TV channel and is destroyed when the viewer changes channel.
ETV and EBIF - ETV Binary Interchange Format
ETV-EBIF is an alternative standard for interactive TV applications for US cable. tru2way (OCAP) requires recent model set-top-boxes to run due to memory and CPU requirements. The cable companies (currently Time Warner Cable) have only just started installing tru2way set-top-boxes at the subscriber's homes. ETV is designed to run on the so-called legacy boxes, most typically the Cisco (S-A) Explorer 2000 and the DCT 2000 from Motorola. These boxes are very common in US homes and it will take several years for the US cable companies to replace these with the newer tru2way boxes. So in the meantime, ETV interactive TV applications can be made available for the legacy boxes.ETV is a binary format, "ETV Binary Interchange Format", also known as EBIF. It is interpreted by a "user agent" which is a native application which runs on the set-top-box which is installed remotely by the cable company.
ETV is particularly suitable for authoring interactive commercials because ETV applications are very compact and can download to the set-top-box very rapidly.