Frequently Asked Questions (continued)

Q: What is switched digital video?
A: [Taken from itvdictionary.com] Switched Broadcast - (a.k.a. Switched Digital Video) - Switched broadcast transmits programs to a subscriber service group only when the subscribers in that group are in the process of watching them, instead of broadcasting all programs to all subscribers all the time. Switched Broadcast enables dramatic savings in bandwidth usage, does not alter the TV viewing experience, and allows the reclaimed network capacity to be used to deliver new and expanded tiers of services and content.

Cable operators are looking to compete with Telcos by adopting the IPTV model using switched broadcast technology and next-generation set-top boxes.

Q: What are Open Cable and OCAP (just renamed True Two-way TV)?
A: The FCC has mandated that there must be interoperability between manufacturers of set-top boxes and other client devices (including televisions and cable cards) and the many Cable MSOs that provide programming to their customers. This is required so that set-top boxes or other client device are not system specific. To meet this mandate, the cable industry formed and has supported CableLabs to pursue new cable technologies and as part of that objective to both establish the Open Cable standards and certify that manufacturers are in compliance with them. In order to do so, CableLabs not only established the standard but also supported the development of the Open Cable Applications Platform or OCAP. This is a middleware software package on which manufacturers and content delivery organizations to build to add applications and other functionalities to their systems.

Q: Where can I learn more about OCAP and Open Cable?
A: The best place to get information on this industry initiative is at www.cablelabs.com. The official home of CableLabs provides a history of the initiatives of the cable industry as well as a complete overview of Open Cable and OCAP (just renamed True Two-way TV).

Q: What is IPTV?
A: [Taken from the iTVdictionary.com] IPTV is next-generation television delivered over a managed network. Depending on how robust the system is, IPTV technology can provide more than just video services; it can provide access to on-demand gaming, data services, digital music and home security. (Interactive Television Networks has launched Pulse, which it claims is the first IPTV music video network. More info.) IPTV technology can provide a single stream to multiple clients simultaneously (multicasting). It can also utilize unicast delivery for providing services to a single client (receiver) for applications such as Video On Demand. Typically video content is compressed using either a MPEG-2 or a MPEG-4 (H.264) codec and then sent in an MPEG transport stream. Live TV is delivered via IP Multicast and on demand services most often use IP Unicast. Using H.264 for compression is of great importance when transporting IP HDTV due to its huge size, but MPEG-2 might still be used for interactivity and other things.

For transmission IPTV might use the Internet, but many IPTV deployments use Internet-like closed networks, as is the case with Telcos. IPTV might also be used over smaller networks such as LANs. IPTV is a system capable of transmitting, delivering, receiving and displaying a video stream encoded as a series of Internet Protocol packets. IPTV can offer great interactivity and virtually limitless programming. Only channels selected by the user are delivered to that user, as compared to many channels being delivered to the user and he/she then chooses which to watch. The switched digital video architecture gives IPTV technology the ability to customize a unique viewing experience for each individual subscriber. IPTV essentially offers a one-to-one signal, providing channels on-demand as opposed to the standard commercial television's 'always on' model. In this 'always on' model of delivery, a huge number of channels are sent to the customer and the customer, via their remote, flips through these delivered channels and decides which to watch. With IPTV, when a customer clicks on a channel, that's when the channel's content is sent for viewing. Each IPTV program has an IP address, and the subscriber’s IPTV set-top box, or related device, finds it. IPTV channel changes typically are faster than the competition. IPTV and other IP-based broadband services can be sent to devices other than a set-top box including phones and portable media devices. Delivery can be over a variety of networks, including WiMAX. With IPTV, the router can beam the signal to a Wi-Fi laptop or desktop computer in that room or even in another room.

Q: What are ETV and EBIF?
A: [Taken from itvdictionary.com] The term "Enhanced TV" is thought to have been officially introduced by NCI (which later became Liberate Technologies) in 1997.

A more technical way to describe Enhanced TV is: the mixing (embedding) of various interactive functions with the television (video) program. This mixed signal is sent to viewers via standard television transmission methods (including the VBI) and/or telephone lines. Viewers with the aid of some sort of decoder (receiver, set-top box, tuner card, etc.) can view and choose to explore these additional features (elements) embedded in the picture.

Often to enjoy Enhanced TV, you can use your TV's enabled set-top box (or equivalent device) or use a PC with a TV tuner card.

(EBIF - Enhanced Television-Binary Interchange Format) - A CableLabs specification for delivering basic interactive-TV applications to older (current) cable provider's set-top boxes as well as newer entry-level boxes that can't operate using cable's primary specification for interactive TV, OCAP. ETV-BIF is based on a simpler binary language, (OCAP is based on Java.) After software is added to these less-sophisticated set-top boxes it can provide basic interactive-TV applications.

Q: What is OnRamp?
A: [Adapted from Informitv] An initiative to provide Java-based software layer for legacy cable set-top boxes.

OnRamp to OCAP, the OpenCable Application Platform, is intended to provide a Java-based layer of middleware that will provide a common interface for first generation set-top boxes incapable of running the full OCAP specification.

OnRamp is intended to be a subset of OCAP so that applications will be forward compatible with the full OCAP specification.

It is based on the J2ME Java 2 Micro Edition platform, used for handheld and embedded devices.

CableLabs, Charter, Cox, Tanberg, TVWorks, Motorola, Philips, Sun Microsystems, Time Warner Cable, and Vidiom Systems are working together to define the new specification, currently known as Java Specification Request 242, or JSR 242.

Glossary

For a complete glossary of terms related to Interactive Television see,

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