News

08/08/2006 - The University of Wisconsin presented DATN at the 2006 Apple Worldwide Developers Conference (WWDC): WWDC 2006 presentation slides (11.6M PDF)

01/18/2005 - MacEnterprise.org and Apple hosted a live webcast on DATN: Watch or download the webcast | Download the slides (3M PDF)

History

The Digital Academic Television Network (DATN, pronounced "Dayton") is the digital replacement for the University of Wisconsin's Academic Television Network (ATN).

ATN previously carried a selection of local television channels, instructional and specialty content from various campus entities, and satellite programming over a traditional coaxial cable network. ATN was essentially a full cable TV network operated by the University of Wisconsin Division of Information Technology (DoIT). However, ATN has reached the end of its life and is no longer maintained by the university.

When it came time to replace ATN, it was determined that the replacement should be more flexible, able to deliver live content via the network in addition to on-demand content, and enable origination of content without costly investments in video equipment. The university's new, high-speed 21st Century Network provides the performance and capabilities necessary to accomodate the needs of this type of high-bandwidth content delivery.

Going Digital

DoIT examined several options for delivering live content digitally based on open standards, such as MPEG-4 and AAC, in an accessible fashion (with novel implementation of services such as closed captioning). A solution based on Apple QuickTime technology was selected. The first phase of DATN is rebroadcasting the same 11 local television channels previously offered by ATN with QuickTime, at a reasonable quality to reach the widest possible range of clients. A wider selection of channels and higher quality broadcasts (using H.264 with QuickTime 7) are planned in the near future.

Each "channel" is broadcast and viewed using several pieces of hardware and software:

Server

• Apple Xserve
  • Mac OS X Server
  • QuickTime Broadcaster
  • QuickTime Streaming Server
  • Apache
  • Custom software for capturing, delivering, and searching closed captioning
  • Custom software for capturing video thumbnails and video archival
• Blonder Tongue ZDM Series TV tuner
• TextGrabber GP500 closed captioning decoder
• Canopus ADVC-100 analog to FireWire AV converter

Network

Broadcasts are inititiated using multicast, which enables any number of clients to view the same stream simultaneously without additional stress on the network. The overall load is the same for one, ten, or one hundred clients. Traffic is also handled such that it does not interfere with other devices on the network. This is made practical and possible by the technical capabilities of the 21st Century Network.

Client

• QuickTime Player for Mac or Windows; provides flexibility and frameworks for items such as custom interfaces and text delivery for segregated closed captioning
• DATN Player; a television-like interface for the Digital Academic Television Network for Mac OS X
• Other media players, such as VLC Media Player, which supports Mac and Windows, as well as other platforms such as Linux and Solaris

...in addition to two foreign language channels and a test version of CNN with Cisco IP/TV encoders.

Equipment

The equipment that comprises DATN is currently housed in DoIT's secure datacenter.

Click any picture below for a larger image:

DATN also includes contributions from the University of Wisconsin School of Journalism and Mass Communication.

Feedback

Feedback about DATN is welcome at feedback@datn.wisc.edu.