• IEEE-1394 wired networks slow to emerge.
• Content producers seek to close “analog hole”.
• HDMI dominates in 2006 digital TV products.

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). Although many fully integrated HDTV sets introduced in 2005 included both an IEEE-1394 and a DVI/HDMI connector, the need to reduce set prices has resulted in most DTV monitors planned for 2006 to include copy-protected HDMI connectors as the sole digital interface. Wired and Wireless Home Networking Arrives in Video Components

Increasing numbers of digital video products introduced in 2006 are 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 2006 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 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 recognize each other instantly for synchronized equipment interoperability.

IEEE-1394 Evolves
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 interface 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 100Mbps, 200Mbps and 400Mbps over a distance of 4.5 meters, and as many as 63 peer-to-peer electronic devices, also known as nodes.

IEEE-1394b Arrives
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 supports 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.

DTCP: The 1394 Gatekeeper
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: Hitachi, Intel, Matsushita, Sony and Toshiba. 1394 Networking Continues To Evolve

Although 1394 was expected to be rapidly embraced for the deployment of high-bandwidth in-home digital networks, politics and licensing costs have driven some manufacturers away from adopting it. Proponents of the interface hope that will begin to change in 2006 and beyond. The use of IEEE-1394 as the in-home network provides two important advantages over Ethernet and IP.

First, 1394 provides enough high-quality bandwidth to carry up to five high-bit-rate compressed HDTV programs on a single wire, and is future-compatible even with the 50-Mbps speeds that will someday be delivered by Blu-ray disc players. Second, 1394 includes 5C copy protection, and a 1394 network can be set up so that it does not connect directly to the Internet.

New 1394 Alliance Appears
Major companies from several industries aligned in 2005 to form the High-Definition Audio-Video Network Alliance (HANA). The group’s mission is to establish a design guideline for secure HD audio visual networks that will speed the creation of higher quality, easier-to-use HD products. Founding members include cable multi-system operator (MSO) Charter Communications; consumer electronics manufacturers JVC, Mitsubishi and Samsung; IT company Sun Microsystems; and media/content supplier NBC Universal.

The group, which expects to see the first HANA-compliant products appear in 2006, will develop guidelines using existing specifications and technologies including IEEE 1394 to interconnect devices. Consumers will be able to view, pause and record more than five HD channels simultaneously from anywhere in the home using one set-top box. Devices from PCs to AV components will share content while keeping protected content secure, control all AV devices and access content with a single remote per room.

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 record them easily; 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, the 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 introduced the High-definition Multimedia Interface (HDMI) in place of, or along side, DVI interfaces. 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 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.

According to the HDMI licensing body, more than 300 makers of consumer electronics and PC products worldwide have adopted HDMI. More than 17 million devices featuring HDMI were shipped during 2005 and 59 million more are expected to ship in 2006, according to market researcher In-Stat.

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 properly relayed 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 as high as five Gbps. The first HDMI products were introduced in late 2003.

HDMI Founders Advance Specifications
The seven HDMI founder companies plan to deliver in the first half of 2006 a new version of the HDMI specification that will include support for higher speed and easier integration into personal computers. The spec will more than double the existing bandwidth to support the demands of future HD display devices requiring higher resolutions, deeper colors and higher frame rates. The spec also will support 30-bit, 36-bit and 48-bit color depths to render over one billion colors.

Also added is greater PC/CE convergence by allowing easier integration into low voltage, AC-coupled PC graphics controllers. In addition to HDMI's current ability to support high-bandwidth uncompressed digital audio and all currently-available compressed formats (such as Dolby Digital and DTS), HDMI will add additional support for new compressed digital audio formats including Dolby TrueHD and DTS-HD.

PC, CE Alliance Proposes HDMI-Compatible Interface
Several leading PC, CE and chip companies announced they are working to develop a specification called the unified display interface (UDI), to serve as the next-generation digital display interface standard for PCs that will be compatible with HDTV signals. The standard also would provide compatibility with CE devices.

A group consisting of Apple, Intel, LG, National Semiconductor, Samsung and Silicon Image was formed to develop UDI specifications. The interface would replace today’s analog VGA standard while ensuring compatibility with the DVI standard. The UDI spec would be fully compatible with HDMI and HDCP. The standard will ensure a universal video connection from the computer to displays. A completed version 1.0 specification is expected to arrive in the second quarter of 2006.

DLNA Looks to Network Standards
The Digital Living Network Alliance (DLNA), representing 21 major promoters and more than 250 member companies including Intel, Microsoft, Panasonic, Sony and Texas Instruments, was formed to create a DLNA ecosystem that provides specifications, interoperability testing, device certification and promotion. The wide range of members includes CableLabs, major pay-TV service providers, CE manufacturers and semiconductor companies.

The DLNA envisions a wired and wireless interoperable network of personal computers, consumer electronics and mobile devices in the home, enabling a seamless environment for sharing and growing new digital media and content services. The DLNA has begun publishing its specifications and is holding “plugfests” regularly to demonstrate what can be done.

The DLNA, so far, has been focusing on Ethernet and Internet Protocol (IP) as its in-home network approach. Limitations to this are related mostly to bandwidth, as the current Ethernet and IP approaches can handle only two or three simultaneous HDTV program streams. In addition, Ethernet and IP in-home networks can be connected directly to the Internet, which may pose content security issues.

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 broadcast 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.

Broadcast flag-enabled receivers, which were mandated for July 1, 2005, would read the flag signal and the instructions it carries on how to treat the content. Various “authorized technologies” implemented in receiving and recording equipment would limit a user’s ability to distribute the content via the Internet or other mass distribution methods.

The Broadcast Flag, which initially applied 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 May 6, 2005, the U.S Court of Appeals for the D.C. Circuit struck down the FCC's broadcast flag regulation, ruling that the FCC exceeded its authority in adopting it. The court's decision shifted the broadcast flag issue to Congress, where the motion picture industry and broadcasters were pressuring lawmakers to pass broadcast flag legislation. The court pointed out that the broadcast flag affects receiver devices only after a broadcast transmission is complete. But the FCC only has authority to regulate receivers, “while those apparatus are engaged in the process of receiving a television broadcast,” the Court said.

Content Producers Look to Plug “Analog Hole”
Undeterred by the federal district court ruling to overturn the FCC’s broadcast flag mandate, interests among the movie and TV broadcasting industries continue to push for legal and technical measures that would eliminate distribution of unprotected high-definition TV content. Increasingly, this has drawn attention to broadband component video connections that ship high-definition signals through a so-called unprotected “analog hole”.

Although by some estimates as many as six to 12 million digital television sets and monitors were sold exclusively with such inputs since 1998, content producers are working to require the ability to “down convert” high-definition content to enhanced definition 480p or 540p form in next-generation products, including high-definition optical disc players and cable and satellite set-top boxes. Content interests would like to see new laws and technologies that would re-impose the broadcast flag or authorize the FCC to impose such systems.