Digital media receiver encyclopedia topics

Functionality and capability

A digital media receiver can connect to the home network using either a wireless (IEEE 802.11a, b, g, and draft n) or wired (Ethernet) connection. A DMR includes a user interface that allows users to navigate through their digital media library, search for, and play back media files. Different DMRs are designed to handle different tasks. Some DMRs only handle music; some handle music and pictures; some handle music, pictures, and video; while others go further to allow internet browsing or controlling Live TV from a PC with a TV tuner.

Some other capabilities which are accomplished by DMRs include:

Watch, pause, & record live television
Play and store music CDs and view album art
Play, catalog, and store DVD videos
Listen & Pause Digital Radio
View, store, and edit digital pictures
Create automated picture slideshows

Hardware

Some DMRs have integrated displays and speakers. Others must be connected to an external output device, such as a television, or a stereo system. While there are stand-alone digital media receivers such as the Apple TV, it is not unusual to find the DMR functionality integrated in other consumer-electronic appliances, such as gaming machines (for example, the Microsoft Xbox 360), DVD players, set-top boxes, or even connected HDTVs (such as HP MediaSmart Connect and MediaSmart TV).

History

An early version of a DMR was presented by F.C. Jeng et al. in the International Conf. on Consumer Electronics in 2002. It included a network interface card, a media processor for audio and video decoding, an analog video encoder (for video playback to a TV), an audio digital to analog converter for audio playback, and an infrared receiver for remote-control-interface. The concept of a digital media receiver was also introduced by Intel in 2002 at the Intel Developer Forum as part of their “Extended Wireless PC Initiative." Intel’s DMR was based on an Xscale PXA210 processor and supported 802.11b wireless networking. Intel was among the first to use the Linux embedded OS and UPnP technology for its receiver. Networked audio and DVD players were among the first consumer devices to integrate DMR functionality. Examples include the Philips Streamium-range of products that allowed for remote streaming of audio, the GoVideo D2730 Networked DVD player which integrated DVD playback with the capability to stream Rhapsody audio from your PC, and the Buffalo LinkTheater which combined a DVD player with a DMR. More recently, the Xbox360 gaming console from Microsoft was among the first gaming devices that integrated a DMR. With the Xbox360, Microsoft also introduced the concept of a Windows Media Center Extender, which allows you to access the Media center capabilities of your PC remotely, through your home network. More recently, Linksys, D-Link, and HP introduced the latest generation of DMRs that support HD video playback and may integrate both Windows Extender and traditional DMR functionality.

Streaming and Communication protocols

While early DMRs used proprietary communication protocols to interface with media servers, today most DMRs use standard-based protocols based on UPnP (Universal Plug and Play) and DLNA (Digital Living Network Alliance). DLNA-compliant DMRs and Media Servers guarantee a minimum set of functionality and proper interoperability among DMRs and servers regardless of the manufacturer.

Connections

There are two ways to connect an extender to its central media center or HTPC server - wired, or wireless.

Wired

Ideal for performance, wired CAT-5 or other ethernet connections allow transmission of video and sound up to whatever limit the routing device used can handle. Using a wired connection, minimal or no congestion will be experienced as a result of bandwidth limitations. However, this method may require substantial work to connect if no cables are already available within the home, usually involving drilling new holes and fishing wire. Alternatively, one may wish to use a wireless connection, as described below.

Wireless

Ideal for convenience, a wireless connection can be established between the media extender and its central media center. On the downside, interference may cause a "less than optimal" connection and cause network congestion, resulting in stuttering sound, missing frames from video, and other anomalies. It is recommended that an 802.11a or better be used, and over as short of a distance as possible.