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The April 7, 2006 Issue Provided by System Dynamics Inc.
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Two Approaches to Networked Digital Video: DLNA and HANA

Digital video is taking its place front and center in the home. Digital TV sales are accelerating. Analog broadcast TV is disappearing in favor of digital broadcast; satellite TV is all digital, and cable is moving in the same direction. Digital audio and video are carried over the Internet. DVR technology appears in consumer electronics equipment, set-top boxes and PCs.

Millions of consumers are using DVRs to watch what they want, when they want. Now they want to choose where to watch--they'd like to watch video that's been recorded and stored on a device in one room on a screen in another room. (They also want to view it from outside the home, but that's a subject for another article.)

Moving video from room to room while providing DVD-like controls (play, stop, pause, fast forward) is quite complex, especially if the equipment and video service come from different companies. Standards are clearly required to make this work.

New networking technologies will provide the underlying infrastructure for mass-market video networking. Now the issue is getting these products to talk properly with each other -- especially to enable top-quality video and audio, and to allow proper controls.

The emergence of networked video is bringing three technology worlds closer together. The information technology, consumer electronics and multichannel video industries have traditionally operated fairly independently of each other. Working out the standards for networked digital video forces them into contact. Each brings a different world view and therefore sees different requirements and priorities for networked digital video.

Two industry standards are emerging to address these needs. We've long followed the Digital Living Network Alliance (DLNA), which is promoting a standards-based approach coming largely from the IT world. The High-Definition Audio-Video Network Alliance (HANA) is a new alliance from the consumer electronics and multichannel video industries with a more video-centric approach.


Digital Living Network Alliance (DLNA)

DLNA Participants --> Click for larger pictureWith members drawn from across the IT, CE and mobile industries, the Digital Living Network Alliance (DLNA) has taken on the all-encompassing goal of providing interoperable sharing of all digital content "such as photos, music and videos" across all PC, CE and mobile devices inside and outside the house. DLNA announced its first set of interoperability guidelines nearly two years ago, and has since extended the guidelines several times. DLNA says more than 30 devices have now passed its interoperability tests, and 11 have been announced.

In a press conference last month, DLNA announced the latest extensions to its guidelines, and provided a roadmap for the future. The earlier guidelines were focused on servers and players for digital media -- think of PCs providing digital music for remote MP3 players in a standardized way. The new guidelines add many new device classes, including printers and a wide variety of mobile devices--both servers and players. Previous guidelines supported networking over Ethernet and Wi-Fi; the new guidelines add Bluetooth. Devices built to these new guidelines will support the ability for consumers to upload and download media between mobile devices and audio/video products, and to print directly from a mobile phone.

To support digital video, the new guidelines add MPEG4/AVC, one of the primary digital video formats for the next decade, as a mandatory video format. They provide an approach to QoS based on prioritization, and add support for the Real-time Transport Protocol (RTP) often used to carry streaming audio and video over the Internet.

DLNA's roadmap includes new guidelines for content protection, described as "link protection for commercial content". DLNA says these guidelines, anticipated for release in the middle of this year, will "lay the necessary groundwork to introduce commercial content into the DLNA network."


High-Definition Audio-Video Network Alliance (HANA)

HANA Board --> Click for larger pictureThe High-Definition Audio-Video Network Alliance (HANA) was formed in 2005 specifically to address the networking of high-definition audio and video. HANA is focused on "the end-to-end needs of connected, high definition, home entertainment products and services." Its founder members include JVC, Mitsubishi and Samsung from consumer electronics; NBC Universal and Charter Communications representing multichannel video content and distribution; and Sun from information technology.

Last month we talked on the phone with Jack Chaney of Samsung, chair of HANA's technical work group, and Bill Rose, President of WJR Consulting Inc. and Chairman of the Consumer Electronics Association (CEA) R7 Home Networking Committee. When we asked about the relationship between DLNA and HANA, they said "there's a philosophical difference -- DLNA is trying to do everything with one network." HANA believes that entertainment content has different networking needs than data and personal content, and that different networks are required to fully meet these different needs.

Like DLNA, HANA is not inventing new standards, but selecting those it believes appropriate for its applications. Its narrower focus has led HANA to select a different set of proposed standards than those chosen by DLNA.

As the basis for its networking, HANA has chosen IEEE 1394 (FireWire), which HANA believes is much better for streamed audio and video than the data-oriented IEEE 802 standards (Ethernet and Wi-Fi) chosen by DLNA. 1394 is a synchronous network designed to carry isochronous streams, ideal for audio and video, which are highly sensitive to timing. 1394 includes the ability to reserve bandwidth, so that each stream runs in its own bandwidth without sharing. 1394 also includes support for the DTCP content protection standard accepted by content providers.

HANA's approach is to have the entertainment video stored at its originating CPE and to use 1394 to deliver and render it wherever needed. IEEE 1394b is designed to operate over distances of 100 meters and can be carried over many forms of cabling including fiber and Category 5e and 6 UTP. HANA is enthusiastic about using existing coax to connect clusters of consumer electronics equipment throughout the home. Many technologies for data over coax can carry 1394; ultra wideband (UWB) over coax should provide at least 400 Mbps and perhaps 800 Mbps.

To support the higher levels of networking, HANA has embraced a set of home networking specifications developed by CEA R7 over the past few years. These include CEA 2027-A (a TV-based user interface for control of networked devices), CEA 931-B (for communicating remote control commands between devices), and CEA 851-A (which specifies network architecture and communications protocols).

HANA is trying to address two key consumer problems: the complexity of interconnection, and the multiplicity of remote controls. Its theme is "One Cable/One Remote".

Using 1394 would simplify interconnection. Today, A/V components are connected with a wide variety of analog and digital interconnect cables, each going from the output of one device to the input of another. By contrast, 1394 is a simple bus system--each device needs only a single 1394 connection to connect to all other devices. In a digital A/V network, the vast maze of confusing and expensive A/V cables could be replaced with a single 1394 cable to each device and an inexpensive 1394 hub to connect them together.

HANA wants to do away with the separate remote controls for A/V players in the same room. Using a single remote control, the consumer will sit in front of the HDTV, access the program guide from a cable set-top box, and then select and watch a TV program. Later, with the same remote control, the consumer can play audio and video content stored on the hard drive of a PC or a DVR.

Many of HANA's decisions are based on timing. Jack and Bill stressed that "HANA wants to launch NOW" and plans to move quickly to complete the specs and bring products to market. Its roadmap shows HANA-ready product introductions--including HDTVs, HD DVD players, and HD PVRs--at CES 2007.

Some of the needed ingredients for HANA's approach are already in place. In the US, the FCC requires cable operators to equip HD set-top boxes with IEEE 1394 interfaces and to support the CEA 931 remote control pass-through standard. Many desktop and notebook PCs are already equipped with 1394 interfaces, and adding them is inexpensive.

Carrying multiple streams of high-definition audio/video around the home is by far the most challenging home networking problem. Audio and video are very sensitive to data losses and delays, which appear as defects in the sound and picture. If the content is coming from a server, buffering and retries could be used to mask the impairments. If the content is streamed in real time, the consumer will hear and see the effect.

HANA's two-network model --> Click for larger pictureHANA questions DLNA's "single network" approach. Rather, it believes the digital home will need two networks--one for data and one for commercial high-quality entertainment--for years to come. In their view, a DLNA-based network is fine for data and personal content, but commercial entertainment content will be isolated to a HANA-based network. A single point connection will provide a bridge between the networks, allowing content from the DLNA network to be viewed on the HANA screens.

Over time, a single network as envisioned by DLNA may satisfy all the needs HANA has identified. Jack and BIll stressed that "In the long run, HANA is not tied to 1394; in the long term, HANA could embrace DLNA." But HANA members seem determined to solve today's problems as quickly as possible.


DLNA and HANA: A Comparison

DLNA and HANA are both trying to give consumers interoperable access to content in a way that fits their needs, rather than operating within the constraints of a given individual device. They are not competitive organizations, but rather groups with different scopes of interest and different priorities regarding what needs to be accomplished and in what timeframe.

DLNA Vision: one network --> Click for larger pictureDLNA represents very broad interests and has a much wider scope, which includes connecting consumer mobile, entertainment and computing devices both inside and outside the home. DLNA wants to enable any consumer media device to access shared media stored on any other device. Its approach does not reflect a sense of urgency; it appears willing to proceed in a stepwise fashion over multiple years to achieve the full scope of its ambitious goals.

By contrast, HANA represents the narrower interests of the consumer electronics and multichannel video industries. With both the content and distribution sectors of the multichannel video industry represented on its board, HANA is tightly focused on video entertainment devices within the home, and perceives an immediate need to create the network for high quality protected video. It draws a sharp line between protected (commercial) content and personal content and is focused on carrying protected content without consumer complaints. HANA acknowledges the broader needs by advocating separate networks for the two types of content; a bridge between them allows personal content to flow anywhere, but keeps protected content within the HANA network.

These different world views lead to different standards choices. HANA has selected 1394 (FireWire) connectivity while DLNA has chosen 802 IP and Ethernet networks. 1394 is isochronous with integral QoS and DTCP content protection; 802 is asynchronous and needs additional mechanisms to provide QoS and content protection. HANA has chosen a deterministic "reservation" approach to QoS while DLNA is satisfied with probabilistic "priorization". DLNA's initial content protection focus is on "link control" which is necessary but may not be sufficient to assure security of high quality entertainment.

Some key companies are members of both groups. To see how this plays out, we'll keep watching whether and how companies incorporate each of these approaches into their interfaces and products.

Both groups expect to have products and demonstrations at next year's CES. We're looking forward to seeing them next January.


For More Information

( www.dlna.org ) ( www.hanaalliance.org ) ( www.samsung.com ) ( www.ce.org/Standards/Committees.aspx )