Home Toys Article
- October 2004 -
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Designing and validating a digital home product to Intel® NMPR conformance places developers at the fore front with a compelling digital home product.
By Steven R. Bard
Overview: Enjoying the Digital Revolution
As consumers acquire and store a growing variety of digital media content, they should be able to share and enjoy their music, photos, and video on a variety of connected devices at anytime and from anywhere in the home. This is the heart of the Intel digital home vision, and its ultimate success depends on a single word: interoperability. But interoperability requires standards.
The Digital Living Network Alliance (DLNA*, initially created as the Digital Home Working Group in June, 2003 by Founders Intel, Sony, and Microsoft with 17 Adopter companies from the Consumer Electronics and Personal Computer Industry) has developed and is promoting the Home Networked Device Interoperability Guidelines v1.0 - a common interoperability framework for use by CE and PC vendors. As the digital media revolution continues to grow, there are many opportunities for companies to design and implement products conformant to the DLNA Interoperability Guidelines and to integrate added value into those products that create a robust consumer experience with products designed to interoperate within the digital home.
Intel has developed a document that, in support of the DLNA Interoperability Guidelines, requires conformance to those Guidelines and provides additional implementation guidelines for technologies that further enhances the consumer experience when a PC is present on the home local area network. The Intel® Networked Media Product Requirements (Intel® NMPR) v2.0 document defines implementation details for technologies such as the UPnP Remote User Interface (RUI), Intel eXtended Remoting Technology (XRT) and, when providing premium content, the Digital Transmission Content Protection over Internet Protocol (DTCP-IP) as licensed by the Digital Transmission Licensing Administrator (DTLA - http://www.dtcp.com). Intel® NMPR v2.0 position is to support the DLNA Interoperability Guidelines for all devices designed to take advantage of the exceptional value the PC is able to extend to interoperable connected devices on the home local area network.
In order to increase opportunities for consumer success with Intel® NMPR products, exceptional execution on EoU is required. Developers must ensure appropriate attention is given to Ease of Use (EoU) practices to provide the best possible consumer experience when using the device. Product success is improved through consistent use of EoU practices and should be a normal part of the criteria required for each phase of a product design cycle.
There have been several white papers, design guides, and tools developed to assist in assessing and improving the ease of use for products' Out of Box Experience and initial use of each portion of the computing environment -- developed by the Ease of Use/PC Quality Roundtable, and publicly available on their website (http://www.eouroundtable.com). White papers are based on data (call center, usability, market research) collected from multiple participating companies, and outline key problem areas, desired user experience, and near- and long-term opportunities for improvement. There are design guideline companion documents for white papers, as well as other tools.
The ability of CE devices and PCs to interoperate smoothly and simply is obviously one of the fundamental keys to a positive user experience. The failure of connected devices to work together as advertised can lead to support calls, product returns, and lost business for retailers, manufacturers, and content providers alike.
While the industry has gone to great lengths to develop UPnP guidelines, networking protocols, and data compression standards, actually implementing them remains the challenge. Going with a proprietary implementation can involve a great deal of time-consuming effort and also involves the substantial risk that the product may not work with another solution from a third-party vendor.
The digital media revolution requires interoperable CE products that are differentiated with value added technologies that drive consumer adoption. Intel® NMPR v2.0 was written to enable development of product with baseline interoperability conformant to DLNA Interoperability Guidelines v1.0 and provide a very robust consumer experience by defining a set of product differentiating technologies that assist developers in delivering innovative digital home products.
Advantages of Intel® NMPR v2.0
Technologies Found inside Intel® NMPR v2.0
DTCP-IP* is a common industry specification with endorsements from content creators. DTCP-IP is a link protection protocol used to encrypt content for transmission from where it is stored on the home network to where it is decrypted for viewing, listening and/or recording. DTCP-IP is suitable only for short-range transmission of content across a local area network such as that found in the home. DTCP-IP seeks to circumvent unauthorized copying of content during transmission.
Premium content delivered to the home may be encrypted and have certain associated rights for viewing and/or copying. The encryption scheme and the associated rights are referred to as Digital Rights Management (DRM). There are a number of proprietary DRM technologies used to deliver premium content to the home - none interoperable with any other DRM. Examples of DRMs may include conditional access mechanisms incorporated by cable and satellite distribution systems or technologies developed to deliver premium content to personal computers in a home via a broadband Internet connection. Another type of DRM is Content Scramble System (CSS) used in commercial Digital Versatile Disk (DVD) production.
The DTLA provides a definition for premium content in the "Digital Transmission Protection License Agreement" (Section 2, clause 2.3 of Exhibit B). In summary, commercial entertainment content (a.k.a. premium content) is audio, video, text and/or graphics that has not been created by the user of DTCP-IP, available for commercial purchase on a general basis, and includes some control method for delivery and, or, use. Examples include:
A consumer may be presented with a variety of DRM schemes when subscribing to different sources of premium content.
Content protected by known (and future) DRM schemes should be brought together into a secure location where it may be transcrypted from the original DRM into a common, single copy protection mechanism that preserves the digital rights information of the original DRM. DTCP-IP is the protocol that will be used to protect premium content in transit on the home network.
The PC, Set-top-box (STB), or other device with sufficient computing capability are examples of devices capable of consolidating content protected by DRMs and transcrypting from the DRM into DTCP-IP for distribution on the home network. Such devices provide a source of DTCP-IP protected premium content for distribution to rendering and/or recording devices on the home network.
Without a standard content-protection transmission technology a rendering device would require an implementation of all DRMs used to protect premium content. Such a device may have limited market appeal due to excessive cost as both a stand-alone device and/or an integrated module. Additionally, premium content protected by a future DRM technology may not be render-able on devices already in the field unless they included a mechanism for in-field updates.
The computing device on the home network may accept premium content that may be protected by a variety of DRM technologies. The computing device transcrypts from the DRM technology to DTCP-IP and then transmits the content to an authorized DTCP-IP rendering device. Integrating DTCP-IP into a device enables it to receive all premium content from the computing devices on the home network. Implementing a single, standard copy protection mechanism lowers cost - whether for a stand-alone rendering device, such as a digital media adapter (DMA) or a module for integration into a more traditional consumer electronics device, such as a television or DVD player.
UPnP Remote User Interface (RUI) is an open standard developed by the UPnP Forum and is available now for review and implementation (http://www.upnp.org/). UPnP RUI allows an application and it's user interface (UI) to be executed on different platforms. Utilizing the UPnP RUI capability on PCs and TV-connected Digital Media Player (DMP) devices for example, allows the PC to deliver hundreds of new services and content channels to the TV, in addition to those already available from the set top box. Wireless devices, in particular, greatly benefit from the deployment of UPnP RUI.
UPnP Remote UI Standard - Overview
The UPnP Remote UI Server functions in a manner very similar to a UPnP AV Media Server Content Directory Service in that it principally exposes Extended Markup Language (XML) listings containing Uniform Resource Identifiers (URI) that correspond to remote-capable applications. A UPnP RUI Client device functions in a manner similar to a UPnP AV Media Renderer in that it can accept requests from a control point to connect to a specified, remoted user interface. The UPnP RUI Client additionally possesses the ability to initiate locally a connection by selecting from a listing of UIs pushed to it from a client control point. A UPnP RUI client can also receive text messages pushed by a control point. Finally, a UPnP RUI client can marshal and forward key input from another device.
UPnP RUI requires at least one common, peer-to-peer remote transfer communication protocol to be supported for basic device interoperability. UPnP does not define the remote transfer protocol, therefore, the remote transfer protocol is considered to be "out-of-band" with respect to the UPnP device.
Once connected, a remoted application and a UPnP RUI client device employ the out-of-band communication protocol to transmit I/O events (key presses, display updates, etc.). As with media formats in UPnP AV, the UPnP RUI Device Control Protocol (DCP) does not specify any particular out-of-band protocol as required for compliance with the UPnP RUI specifications. UPnP RUI only defines a standard action that allows a client device to enumerate its supported protocols. This is done for the purpose of checking compatibility with application listings. Intel® NMPR v2.0 however, requires all Intel® NMPR v2.0-conformant UPnP RUI client devices to support Intel XRT2.1 remoting protocol as baseline capability, to ensure a minimum level of interoperability.
UPnP RUI Server Device
The UPnP RUI Server supports a single UPnP device service that allows control points to browse listings of applications that are remote-capable. In addition, the UPnP RUI Server is a virtual device, serving listings of application UIs. The URIs identifying the application may be associated with other devices within the home network. The listings are composed of user-friendly metadata, URIs identifying the remote-able application user interfaces, and optional application and protocol-specific technical information for each UI. The form of the returned listings is XSD schema-based XML. In creating a request for listings, a UPnP RUI Server may be requested by a UPnP RUI Server control point to only expose listings of remote-capable applications that employ a specific remoting protocol (for example, Intel XRT2.1). The control point may further request the UPnP RUI Server to only return listings that match the contents of some specific metadata field (for example, name="*chess*"). Finally, the UPnP RUI Server enables a UPnP RUI Server control point to set/get the connection initialization policy for a given application. (For example, whether or not connecting to a URI will result in a 'fresh' application state, or an in-progress application state.)
UPnP RUI Client Device
The UPnP RUI Client supports a single UPnP service that allows control points to set up and manage connected UI sessions on a given client. The UPnP UI Client service allows a UPnP RUI client control point to post listings of client device-compatible remoted user interfaces directly to the client itself. UPnP RUI Client devices may support receiving simple text messages from UPnP RUI control points. UPnP RUI Clients may support the ability to receive key input from another network device. This capability allows a UPnP RUI Client to act as a proxy for another network device with respect to the remoted application.
UI Discovery and Connection Models
The UPnP RUI Device Control Point (DCP) allows for many models for the discovery of remote-capable UIs and connecting them to RUI client devices.
The Intel® NMPR v2.0 client discovery and connection model requires that the UPnP RUI Client device support three optional client services (see Figure 1). There is no UPnP RUI Server service - only a UPnP RUI client control point is employed in this model. Intel® NMPR v2.0 client devices utilizing this discovery and connection model are generally higher-end, and may have interactive UIs. In this model, a UPnP RUI control point acquires UI listings (either through some out-of-band means or via browsing a UPnP RUI Server) and posts them directly to the UPnP RUI Client device. The posted listings appear overlaid on the device 'local' UI. The user executes a connection simply by selecting one of the listed UIs.
Figure 1. Intel® NMPR v2.0 client connection model
Similar to media format support in UPnP AV, UPnP RUI requires at least one common remote transfer protocol to be supported for basic device interoperability. XRT2.1 is an Intel-developed, binary protocol requiring only minimal overhead on remoting clients by utilizing the generally greater computational power available on remoting servers. XRT2.1 is a stateless protocol that does not require caching of UI elements and can be implemented with a comparatively small software stack. While device vendors may chose to support additional remoting protocols, requiring XRT2.1 support by Intel® NMPR v2.0 client devices effectively ensures an interoperability baseline among all client devices. Intel XRT 2.1 specification and sample implementation is available for free download on the Intel® Developer Network for the digital home
Get You There
To speed the implementation of industry specifications such as UPnP, UPnP Audio Visual (AV), and UPnP RUI, Intel provides a comprehensive suite of development authoring tools consisting of ready-to-use object code that has been pretested for Intel® NMPR conformance.
The following tools are available for download at no cost:
Transcoding is the process of converting one media format into another, enabling DMAs located around the home to consume images, audio and video stored on a PC in a variety of formats. DMAs are limited in the number of media formats they can directly support. Intel® Software for Media Transcoding enables the PC to convert media formats to make them playable by DMAs.
Support for network members also includes 10 hours of tutorial videos on UPnP technology and available Intel tools, prepared by the Intel senior development engineering team. Members of the Intel® Developer Network for the digital home also have access to a dedicated e-mail support hotline.
The Intel® Developer Network for the digital home also provides access to two other important tools:
Both Intel® CTT and ITT test tools (Figure 3) generate a log file. Once sent to Intel, the log file qualifies a solution for an optional listing in the online solutions catalog.
Achieving Intel® NMPR validation is a matter of following the steps and using the tools, and the results can be dramatic. Using the tools enabled one device manufacturer to go from a purely proprietary solution to an Intel® NMPR-validated solution in only three days.
Intel recognizes the strong requirement for interoperability and encourage all digital home product developers to design in conformance to the DLNA Interoperability Guidelines v1.0 and incorporate the advanced technologies defined in Intel® NMPR v2.0 to assure a robust consumer experience.
Designing and validating a digital home product to Intel® NMPR conformance places developers at the fore front with a compelling digital home product. Intel® NMPR conformance enables companies to meet conformance to DLNA Interoperability Guidelines v1.0 while taking advantage of interoperable implementation guidelines for leading technologies such as UPnP RUI and DTCP-IP.
Developers must ensure appropriate attention is given to implementing Ease of Use practices at each phase of the product development cycle so as to increase the chance of product success when the consumer interacts with the product during their first out-of-box-experience with the product
Intel announced the preview release of building block products for Intel® NMPR v2.0 at the Fall 2004 Intel Developer Forum.