IP broadcasting over analog TV networks may soon be standardized.
Valerie Thompson
Europe's TV broadcasters are increasingly using their networks for the distribution of multimedia and Web content. While digital satellite TV networks may seem to be the premium choice for this application, analog TV has the advantage of a large existing customer base. Analog TV is also a less expensive option than other networks.
Germany's TV station ZDF, for example, launched a new service last November. Decoder manufacturers expect that by the end of this year, more than half a million users will equip their PCs with the required hardware. In addition, SwissTXT and French Le Cinquieme are also launching Webcasting services, exploiting the vertical blanking interval (VBI) of analog TV signals that used to carry just teletext services.
"VBI is three to five times cheaper than off-peak dial-up access, as long as the broadcaster does not charge ridiculous amounts for its service," says John Clancy of Bocom International, a datacast software vendor.
In addition, new software that will be released this spring helps service providers and enterprises create robust push applications for analog TV networks (
see the table
). These VBI-enabled broadcast systems package and distribute multimedia content and control subscription, authentication, and scheduling of transmission. Some applications include "grabber" functionality that takes Web pages from the Internet and directly inserts them into the VBI, which makes VBI much more attractive to Web content providers because of the built-in payment or royalty mechanisms.
The Internet Engineering Task Force (IETF) is currently reviewing a specification proposal for an IP-ov
er-VBI protocol for Europe's PAL TV networks issued by Philips and the International Datacasting Association (IDA). According to Clancy, who is also chairman of the IDA's IP/VBI working group, "There is strong momentum to reach a consensus within the next six months." This would mean the standard could emerge by the end of this year.
The proposed IP/VBI protocol is an extension of the IP multicasting standard. It overcomes TCP/IP's need for two-way communications and allows IP data packets to travel over broadcast network's one-way communications architecture. The protocol will also enable applications to receive the data from the VBI via standard IP addressing.
"We are already modifying our firmware to comply with IP/VBI, as we expect the standard to emerge in the next six months," says Clancy. Microsoft has already implemented an IP/VBI protocol in Windows 98 for the North American TV system (NABTS).
Therefore, provided the standardization
proceeds smoothly
, the implementat
ion of IP/VBI in PCs and set-top boxes will have a profound effect on the global datacasting industry. Different manufacturers' systems will be able to operate together, and within three years, PCs throughout the world could come equipped with cheap VBI decoders.
| VBI-Enabled Datacasting Software
|
|---|
| Product and Vendor
| Supported platforms
| Features
|
|---|
NetCast 2000
Bocom International
+353 1 660 1550
http://www.bocom.ie/ | Server: Windows 95/NT
End user: Windows 95
| * Real-time feed
* E-mail alert
* Web-page broadcast
* Teletext to Web broadcast
* File transfer
* IP multicasting
|
SkyWeb
SkyData
+39 6320 7300
http://www.skydata.it/
| Server: Windows 95/NT
End user: Windows 95
| * Real-time feed
* E-mail alert
* Web-page broadcast
* Video/audio streaming
* Live streaming
* File transfer
|
Media Distribution System
The Fantastic Corp.
+41 41 728 88 88
http://www.fantastic.ch/
| Server: Windows 95/NT
End user: Windows 95
| * Real-time feed
* Web-page broadcast
* Video/audio streaming
* Live streaming
* File transfer
* IP multicasting
* Business TV
|
Carocast and NeTTV
Cabot Software
+44 117 958 6644
http://www.cabot.co.uk/
| Server: Windows 95/NT
End user: Set-top box with 68 KB
| * Advertising
* Program-related Web-page simulcast with TV broadcast* IP multicasting
|
Intercast
Intel
+49 89 991430
http://www.intercast.de/
| Server: Windows NT
End user: Windows 95
| * TV-program-related Web content or enhanced TV
* Packaged news and information
|
illustration_link (22 Kbytes)
If standardization proceeds smoothly, many PCs throughout the world may soon be equipped with cheap VBI decoders.
The Web Over Plain-Vanilla TV
