MPEG-FAQ 4.0:

Xing Distributed Media Architecture

{XDMA} Network Description

The Xing Distributed Media Architecture ("XDMA"), developed by Xing Technology Corporation
("Xing") is the first commercially available low-cost solution for world-wide and local network
delivery of live and on-demand video+audio.  The National Broadcasting Company (NBC) has
broadly deployed XDMA for broadcast delivery of financial news programming to subscribers in
the U.S and Europe.  New applications are being developed with XDMA for distance learning,
corporate communications, news delivery and computer based training in corporate,
educational, government and health care markets, employing wide area, local area and ISDN
networks.

How XDMA Differs from other Video Networks

Existing "on-demand" multimedia (video) network architectures are based on tightly coupled
point-to-point client-server communication, which result in 4 major limitations:

	1.  significant interaction is required between client and server for flow control,
		requiring complex server programming and signficant data overhead (on
		the order of 25% - 50%);

	2.  servers are not designed to deliver the same streams simultaneously
		to multiple users, making "live" delivery to multiple users impractical;

	3.  LAN-based server architectures are not designed to operate (and generally
		don't work well) over wide area networks; and

	4.  communication protocols employed are proprietary, and do not directly support the
		TCP/IP international standard

XDMA represents a significantly different multimedia network architecture, based on the
concept of "streaming media".  This architecture supports both "on-demand" as well as "live" It
video and audio delivery which does not require close coupling between the client and server.
It easily supports "broadcasting" or "multicasting" of live or on-demand content to multiple
simultaneous users over local as well as wide area networks.  The benefits of XDMA are
reduced network component complexity, significantly increased network flexibility, and
significantly reduced network overhead.  Moreover, Xing's approach is built around
international standards-based components - Unix and (in 3rd quarter 1995) Windows NT
servers, TCP-IP connections, MPEG video and audio compression, and HTTP-HTML client
server communication.  This allows better economies in implementation and easy integration
into existing communication networks.

Technical Description

XDMA was developed as a client-server media distribution architecture which can operate
independently or complement existing WWW (World Wide Web) HTTP / HTML architectures
on local area networks, private data wide area networks and public data wide area networks
(e.g. Internet).

XDMA delivers *streaming* multimedia - pictures, video and sound - based on the MPEG
international standards for video and audio compression from Unix and (in 3rd quarter 1995)
Windows NT servers.  When integrated with WWW, XDMA augments existing WWW
architectures by providing a Common Gateway Interface (CGI) to existing Web (HTTP)
servers, and viewer extensions to popular "Web HTML browsers" (i.e. Mosaic, Netscape,
Winweb, Spyglass, etc).  As such, XDMA can take advantage of user authentication
procedures as supported by current Web browsers and HTTP servers.

Streaming of multimedia data is a significantly different way of delivery, as the user can view /
hear the data as it is being transmitted instead of waiting for file transfer completion, and there
is no requirement for complex file systems such as Netware or NFS.

In addition, XDMA uses standard TCP-IP network protocols, and takes advantage of new
"multicast IP" protocols (RFC 1112) for data delivery, allowing multiple users to simultaneously
view / hear the same data streams without duplication of data or use of intrusive broadcast
protocols.

A typical XDMA configuration will include some of the following components:
	* XDMA Network Encoders
		- video+audio
		- audio only
		- file transmitter / encoder emulator
	* XDMA Network Servers
	* XDMA Network Clients
		- for PC Windows
		- for X-Windows
		- Standalone
	* XDMA Network Routers
	* XDMA Network Editors
	* XDMA Network Manager
as described below.

XDMA Benefits

	* compatible with existing enterprise TCP/IP networks, including Ethernet,
		ATM, FDDI, ISDN, T1 and Frame Relay
	* adds live and on-demand video and audio services to private and public WAN's
		and LAN's without infrastructure changes
	* low overhead (3%) video and audio streams are fully routable
	* all network components are SNMP manageable (3rd quarter 1995)
	* network congestion is controlled by on-the-fly bitrate reduction of video and
		audio streams;  streams are scalable from full rate down to ISDN
		BRI (56-128kbps)
	* SQL database management of XDMA streams (3rd quarter 1995)
	* servers may be distributed for load balancing and stream caching
	* software-only and hardware accelerated video and audio decode provided
		on client systems
	* user interface customizable through HTML / HTTP (Web / Mosaic) interface
	* compressed video and audio streams compliant with MPEG-1 and MPEG-2
		(ISO/ICE 11172 and 13818) international standards
		


XDMA Applications

Applications requiring "media on-demand" benefit from XDMA's simplified approach.  The
advantage becomes most apparent in applications with a combination of "on-demand" and
"live" media delivery requirements, especially when the clients are geographically dispersed.
NBC is using XDMA to deliver multiple simultaneous live financial and news video broadcast
channels to financial market subscribers (money managers, stock brokers, financial analysts)
in cities throughout the US and Europe as part of their "NBC Desktop Video" service.  Xing is
developing similar delivery services for other commercial TV and radio programmers.

Although commercial broadcast services provide very visible and compelling examples for
Xing's capabilities, the largest volume applications for "streaming media" will  be in corporate,
educational, government and health-care networks with "on-demand" and "live" communication
requirements, including training, presentations, status reporting, and occassionally,
entertainment.  Because of the rapid proliferation of TCP-IP / HTTP / HTML ( Internet + World
Wide Web + Mosaic), the infrastructure for integration of Xing "streaming media" architectures
is quickly developing.

Representative XDMA applications include:

	* Commercial broadcast delivery systems;
	* Internet Service Provider delivery of radio and TV programming;
	* On-line marketing, sales, service and customer support;
	* Enterprise-wide training, corporate information systems and regulatory
		compliance;
	* Medical information systems, including live monitoring and on-demand
		multimedia information retrieval;
	* Educational systems for live and on-demand distance learning as well
		media production;
	* Government networks for live and on-demand delivery of news events
		and briefings to policy makers and dissemination of public information;
	* Media production and distribution; and
 	* Information archives

XDMA and ISDN

XDMA is ideally suited for ISDN remote access server and regional server applications such as
distance learning and news delivery, through its ability to provide on-the-fly MPEG stream
bitrate reduction and service of large numbers of simultaneous users.  Xing is currently
developing a reference platform for ISDN regional servers which delivers both high resolution /
low frame rate as well as low resolution / 30 frame per second video streams.  Demonstration
of this capability will be available via Xing's World Wide Web site - http://www.xingtech.com, as
well as via direct ISDN dial-in - 805/473-7200.

Xing Technology Corporation

Xing is the world's leading producer of PC based software technologies and products for digital
compression and decompression of video and audio in accordance with the MPEG (Moving
Pictures Expert Group) international standards.  Technology licensees include Microsoft, Intel,
Pacific Bell, NTT Japan, Fujitsu, Hewlett Packard and IBM.  In addition, Xing provided the key
technologies to NBC for the development of the first wide area digital video broadcast delivery
system ("NBC Desktop Video").


Glossary

MPEG  -  Motion Picture Experts Group.  The international standards for compression of video
and audio.  There are actually two standards - MPEG-1 (ISO/IEC 11172) and MPEG-2
(ISO/IEC 13818).  MPEG-1 was originally designed for delivery of video to consumer devices
at single speed CD-ROM data rates (150kbytes/sec), and is therefore lower resolution and
lower quality than MPEG-2, which was designed for delivery of broadcast and HDTV quality
video.  Each MPEG specification actually has 3 parts which define the video stream, the audio
stream and the video+audio encapsulating transport stream.

TCP-IP  -  Transmission Control Protocol + Internet Protocol.  A collection of communications
protocols (including TCP, IP, UDP, ARP, IGMP, ICMP, RAP, RIP, SNMP) that are the basis of
the Internet and all Unix networking.  Because TCP-IP can support both local and wide area
networking, while Novell's Netware protocols were designed only to support local area
networking, TCP-IP is rapidly become the standard as well for PC Windows networking
through an interface called "WINSOCK".

HTML+HTTP  -  Hypertext Markup Language + Hypertext Transport Protocol.  HTML is a page
description language and HTTP is a communications protocol that runs on top of TCP-IP.
Combined, HTML+HTTP define the basis for applications such as Mosaic and Netscape, which
are the primary tools for navigating the Internet's "World Wide Web".  HTML defines the
contents of pages which are viewed on the "Web", and HTTP defines the way an HTML
browser talks with an HTML server (refered to as an HTTPD or Web server).  It is important to
note that HTML+HTTP can be used on local area networks and private data networks, and are
rapidly becoming the standard for in-house corporate information systems which are not
necessarily Internet connected.

URL=http://xingtech.com/