Keith Dunford /
06.01.2005
Originally featured on BroadcastEngineering.com
XVD's CamCast Professional wireless digital streaming system


In trials by several broadcast networks in Japan, the wireless and wired systems were used in HD and SD live event capture and distribution throughout the country.

A large part of NAB2005 was devoted to HDTV. Many companies showed advances in technology and products that add capability and flexibility, or that can improve performance in HD live event capture and distribution, with particular focus on sports.

One such company, XVD, demonstrated its lightweight HD encoder and wireless system for real-time capture of live events. The advanced digital signal processing and compression technology provides greater efficiency and performance in handling real-time HD and SD content, while adding flexibility to field operations with a camera-mount system designed specifically for sports and other live events.

The company's compression technology delivers up to a 5:1 improvement in robustness of processed content when compared with MPEG-2 operating at an equivalent data rate. And more HD or SD content can be processed and distributed within the same network bandwidth. For example, a wide range of sports and entertainment content in the 1080i and 720p format was demonstrated and compressed in XVD at data rates of 10Mb/s and 7Mb/s.

Most experts who witnessed the demonstrations considered the quality and performance equivalent to current HD network distribution feeds operating up to 45Mb/s. In addition, degradation of performance at lower data rates was more graceful, and artifact generation was less noticeable and less abrupt than with other compression standards.

Similarly, the demonstrations of live event capture using the company's CamCast Professional wireless system at 5Mb/s and 7Mb/s provided excellent HD quality with greater efficiency. This significant increase in capability offers several possibilities to production companies, such as relaying multiple HD live event cameras at data rates of 5Mb/s to 7Mb/s over satellite or telco networks to central production centers. In some circumstances, this could eliminate the need for on-site production facilities.

Another significant feature is that it offers scalability for a wide range of applications, including HD cinema, HDTV, SDTV, corporate communications, video conferencing, video surveillance and streaming applications to laptops, PDAs and cell phones.

During NAB, the company demonstrated an HDTV origination streamed over a standard GSM network to a cell phone display at a full 30fps. The decoder requires minimal processor capacity and can deliver full-motion display within this limited processing. This feature is significant for broadcasters and others wishing to offer added value services or re-purposing of content for the growing mobile market, using a single efficient processing system.



Figure 1. An overview of the XVD CamCast Professional HD wireless system. Click here to see an enlarged diagram.

During NAB2005, XVD introduced the CamCast Professional HD wireless encoder system. (See Figure 1.) The camera-mount system is battery powered by a 10VDC to 17VDC source with a reported consumption of some 8W and packaged in a robust housing designed for field operations. The wireless system processes and compresses 1080i or 720p content and transmits it directly from the field to a production vehicle or satellite uplink at HD data rates as low as 5Mb/s. The company reports it will offer two wireless options, including Wi-Fi 802.11a and COFDM, each presenting unique operational and technical benefits in differing applications.

A variant of the system also is available for HD distribution and contribution networks. It is capable of operating at data rates up to 15Mb/s, which provides for the more robust requirements of these applications. It is designed to interface with conventional telco networks and also provides a 10/100 Ethernet interface for use in LAN or WAN applications.

An SD (PAL or NTSC) version of the wireless system provides compressed content at data rates between 300Kb/s and 3Mb/s. For most applications, a data rate of 1.5Mb/s was sufficient to deliver broadcast-quality content. And at this output data rate, the use of T1 networks provides an attractive networking alternative to more expensive links.


Keith Dunford is a managing partner of The Exam Group, a consulting company engaged in technology evaluation and integration for the Electronic Media and IT industries.



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