Technologies Enable Video Home Networking
• IEEE-1394 standards set for wired networks.
• Broadcast flag systems approved for content control.
• HDMI embraced for 2005 digital video devices.

Digital Interfaces for DTV Proliferate:
Another growing trend in DTV displays is the inclusion of one or more digital interface connectors, typically either a connector based on the IEEE-1394 standard (a.k.a. iLink or FireWire), the Digital Visual Interface (DVI) standard or its updated form called the High-definition Multimedia Interface (HDMI). Many fully integrated HDTV sets being introduced in 2005 include both an IEEE-1394 and a DVI/HDMI connector, while most DTV monitors include copy protected DVI or HDMI connectors as the sole digital interface

In most cases the IEEE-1394 digital interface is used to connect a digital receiver with an HDTV recorder (such as a D-VHS VCR) to record and playback the highest quality programming possible. The connector also can be used to distribute programming to multiple devices connected to an in-home network. The inter face ships digital signals in a manageable compressed form and can include digital networking protocols that allow components to communicate back and forth to simplify the operation of an entire system with minimum commands from users. The IEEE-1394 interface originally was developed by Apple Computer in 1986, and was called "FireWire" for its fast operating speed. In 1995, the Institute of Electrical and Electronic Engineers (IEEE) adopted this serial bus as the 1394 standard. Sony trademarked their name "iLink" for their implementation of the 1394 bus as a four-pin connector. The specification was updated in 2000 as the 1394a standard, supporting speeds of 100 Mbps, 200 Mbps and 400 Mbps across a distance of 4.5 meters, and as many as 63 peer-to-peer electronic devices, also known as nodes.

In 2001, the IEEE 1394b standard was adopted as a network technology. This version is capable of moving data streams at faster speeds over longer distances than the original version. The new form will support up to 3.2 Gbps and additional forms of cable. Speeds as high as 100 Mbps over 100 meters will be supported by 1394b using Category 5 cable, 400 Mbps over 100 meters using plastic optical fiber, and as high as 3.2 Gbps over 100 meters using glass optical fiber. The "b" standard is compatible with the "a" standard at up to 400 Mbps. All 1394 devices support hot swapping and plug-and-play, so components automatically will recognize each other and configure themselves upon connection. The 1394b standard is being adopted by growing numbers of DTV product manufacturers for multi-room networking solutions.

In DTV applications the 1394 interface is safeguarded with the Digital Transmission Content Protection (DTCP) system to prevent the illicit duplication of copyrighted programming. The DTCP system also is known as "5C" for its five developing companies: Intel, Hitachi, Matsushita, Sony and Toshiba.

DVI Selected for Digital Monitors:
Many of the digital television sets, monitors and set-top boxes are equipped with a digital connector designed to relay uncompressed digital signals from a receiver or playback device to a digital video display device. Called the digital visual interface (DVI), the connector ships uncompressed digital video-only signals through what is considered a highly secure pathway.

Because DVI signals are not compressed, current consumer devices cannot easily record them; neither can they be sent out to multiple devices in a digital home network. As with the IEEE-1394’s DTCP system, content passing over DVI connectors also can be protected against copyright violations through a system called high-bandwidth digital content protection (HDCP).

In 2001, CEA's DTV Interface Subcommittee announced a new standard for the uses of DVI called EIA/CEA-861A. The standard defines a method for sending digital video signals over DVI and OpenLDI interface specifications. The standard is fully backward compatible with earlier DVI standards. New features include carrying auxiliary video information, such as aspect ratio and native video format information.

HDMI Arrives:

In 2005 a majority of digital televisions to be introduced to the market will include the High-definition Multimedia Interface (HDMI) in place of or along side DVI interfaces. Final specifications for HDMI were approved in late 2002 by seven developing companies. This new enhanced form of DVI with HDCP is used between any audio/video source, such as a set-top box, DVD player or A/V receiver, and an audio or video display or monitor, such as a DTV. HDMI supports standard, enhanced or high-definition video, plus multi-channel digital audio on a single cable. The format transmits all ATSC HDTV standards and supports eight-channel digital audio (at up to a 192 KHz sampling rate), with bandwidth to spare for future enhancements. Among its many attributes is a reduced connector size, which is easier to run through small holes drilled for in-wall installations and component racks. The HDMI connector uses a 15mm plug with 19 pins and is fully compatible with the former DVI-HDCP standard.

HDCP ­ The DVI/HDMI Gatekeeper:
Not included as part of the HDMI standard, but widely understood to be a necessary compliment to the interface, was the Intel-developed HDCP protocol designed to protect HDMI and DVI signals from piracy.

A key advantage of HDMI is that when the individual devices are enabled, a single remote control can operate everything in a home theater system. The HDMI spec covers the conversion of video formats so that signals on a PC can be relayed properly for display on a TV monitor, for example. The audio stream is serialized and the data packetized for transmission along with the video signal. At the receiver, the two streams are segregated and the data is depacketized for playback.

Because the format was designed as a connection to send uncompressed digital video signals to TV displays, it does not facilitate home networking. Signals are relayed at bit rates up to 5 Gbps. The first HDMI products were introduced in late 2003.

Broadcasters Throw Broadcast Flag:
In November of 2003 the FCC approved a system called the “Broadcast Flag”, which was designed to curb Internet distribution of digitally-broadcasted TV shows. The broadcast flag inserts a tiny bit of data, called a flag, into a station’s digital stream. The flag lets digital receivers know the protection level of the content. Beginning July 1, 2005, receivers delivered to the market will be able to read the flag and the instructions it carries on how to treat the content. Various “authorized technologies” implemented in receiving and recording equipment will limit a user’s ability to distribute the content via the Internet or other mass distribution methods.

The broadcast flag, which initially will apply only to over-the-air digital broadcasts, should not restrict use of digital video recorders and similar fair-use recording devices. Unlike other types of conditional-access systems, there is no provision to limit how the content is used.

On Aug. 4, 2004, the FCC announced that it had approved 13 digital output protection technologies and recording methods, which are to be implemented in digital televisions and other devices capable of receiving over-the-air DTV signals by July 1, 2005.

The FCC classified the 13 broadcast flag content protection technologies in three categories including the following:

• Output Protection – This includes the DTCP, HDCP and TiVoGuard solutions. The DTCP system is designed to protect copyrighted digital content fed over IEEE-1394 connections. It was later extended for use over other connections and Internet protocols for use in both wired and wireless networks. High Bandwidth Digital Content Protection (HDCP) was developed by Intel for use with wired DVI and HDMI connections for uncompressed digital video. TiVoGuard was developed by digital video recorder-pioneer TiVo as a security system that allows con tent to be relayed between a limited number of registered TiVo DVRs.

• Recording Methods ­ These include the CPRM, D-VHS, four derivations of MagicGate, and VDCP. The Content Protection Recordable Media (CPRM) system for video content, developed by IBM, Intel, Matsushita and Toshiba, is an encryption-based technology used to record standard-definition sources on various forms of removable media, including DVD and flash memory cartridges. The Video Content Protection System (VCPS), developed by Philips and HP, also is encryption-based and allows consumers to record DTV broadcasts to DVD+R, DVD+RW and double-layer DVD+R optical discs. The four versions of MagicGate Type R approved by the FCC were developed by Sony. The technology uses both hardware and software to protect content being recorded to Sony's Memory Stick Pro and Hi-MD memory formats. D-VHS was developed by JVC as a tape-based video recording system for both standard-definition and high-definition content. In the recording process, D-VHS scrambles content.

• Digital Rights Management (DRM) – This includes the Windows Media, Helix and SmartRight systems. Microsoft's Windows Media Digital Rights Management (WMDRM) can be applied to protect a wide variety of audio and video content as both an output control and a recording control. Developed by RealNetworks, the Helix DRM protects a wide range of audio and video content across multiple platforms. SmartRight, developed by Thomson and members of the SmartRight Association, prevents unauthorized Internet redistribution of marked digital broadcast content. The system creates a personal private network in the home to thwart piracy and is smart card-based for easy upgrading.

Wireless Home Networking Arrives In Video Components:
Increasing numbers of digital video products introduced in 2005 are being designed to support interconnectivity and interoperability through a process called home networking. Equipment fitted with Ethernet ports and other digital interfaces enable interconnection through wired or wireless pathways to distribute signals from a central room in a home to multiple receiving stations throughout the house.

At the 2005 International CES, a number of companies announced plans to market advanced set-top boxes, networkable DVD players, “media bridge” devices and hybrid home media center PCs with wired and wireless home networking capabilities.

Home networking simplifies the set-up and operation of multiple components in a home theater system, and will permit the distribution of content from the home theater room to multiple entertainment centers in the house. This allows users in different rooms to draw programming from one centralized home entertainment server.

For example, one user could view a program in the living room, while an HDTV signal is produced in the den on a server outfitted with a DVD jukebox or a hard drive-based digital video recorder. This would eliminate duplicate equipment and cabling used for each TV in a household.

Through a network, users viewing multiple TV sets could share devices such as VCRs, set-top boxes and DVD players. This brings cost savings and flexibility of use. Both wired and wireless systems will distribute audio and video content on these pathways. Even bandwidth intensive HDTV programming will be accommodated.

An example of some of the systems that have been developed for wireless distribution systems for home networks include various servers that distribute video over 802.11a, 802.11b and/or 802.11g wireless networks. Some networking technologies employ wireless distribution systems that handle multiple streams of MPEG 2 video, including multiple HDTV streams, with the same performance as a wired system.

Wired systems typically use Ethernet, IEEE-1394 or coaxial cables, which typically deliver large bandwidth for negotiating multiple simultaneous streams and device “hand-shaking” software that enables multiple components to instantly recognize each other for synchronized equipment interoperability.