Rich Media Math
Company puts content delivery in the numbers
By Karen Brown
from the April 16, 2001 issue of Broadband Week
Content delivery startup Digital Fountain has a radical new equation for the rich content delivery world: Don't send the file, send the math.
Using a technology made possible by the magical mathematics of digital data, the company's server product line delivers not the original rich media content but rather complex mathematical instructions for replicating it. It's sort of a recipe sent to user computers for assembling digital ones and zeros into pictures and sound.
The San Francisco-based company claims this will allow content providers to slash delivery costs and support popular streaming media delivery much more efficiently.
Cheryl Haines, Digital Fountain's vice president of marketing, says her company's server products are aimed at solving delivery snarls created by the Internet's governing TCP/IP protocol.
Under TCP/IP, data files are sliced into small chunks, wrapped in packets, transmitted across the Internet and finally reassembled at the destination. The process requires identical data be sent to individual users, and if that content is popular, the number of requests can quickly overwhelm content servers. On the user end, herky-jerky video is the result when packets arrive late or are lost along the way.
In contrast, Digital Fountain's technology sends metacontent files, containing complex mathematic formulas. A 500-kilobyte plug-in installed on the user's computer takes in these files and assembles a clone of the original content.
"With Digital Fountain, instead of taking the file and slicing it into slices, think of what we do as sending the recipe to make bread down the wire," Haines explains. "If you look inside one of our packets you don't see anything that looks like the file. What you see instead are these equations with mathematical metaphor for the content. It allows you on the receiving end to recreate the original content, but what's actually being sent is more like a recipe as opposed to slices of the bread."
Equally radical is how the system handles the Internet plague of disorderly data delivery. In traditional TCP/IP delivery, the user computer must assemble packets in order to play content, and if a packet is lost, it must be found.
In contrast, the Digital Fountain system produces packets each containing some information about the entire file--but none contains any exact piece of the file. So the end user's computer doesn't need to gather all of the packets in order to start playing a file. It can start in the middle of a multicast, or with packets out of order.
"I don't need to get any particular set of them in order to reconstruct the file," Haines says. "If I have 100 packets, I don't have to get packets one through 100 any more. I can get any 100 packets. So if packet 15 is lost, I just have to wait for another packet."
Similarly, this delivery New Math sets multicast transmission on its ear. In TCP, if a dozen people all request the same content, the server has to fire off 12 versions. Digital Fountain's technology allows users to share a common metafile data flow, even if they tap into it at different times. Haines likens it to turning on a water tap--the content starts flowing to the user only when the user taps in, and the continuous supply during the multicast can feed far more users.
"Remember, I am sending out this stream of metacontent to the network," Haines explains. "Katy wants to listen at 1:15 so she joins the stream. Seven or eight minutes later I want to listen. Katy is still joined into the stream, so I join the broadcast as well. Five minutes later, you join the broadcast. Now, did we use three times as much of the network? No, we used the same amount of the network, because as soon as I join I'm getting information that is useful to me."
At a time when content companies are facing dire economic downturns, the system is touted as offering more for less. One Digital Fountain server can manage 4,000 simultaneous streaming media users, compared to about 30 conventional servers needed to handle the same load. For downloads, one Digital Fountain server can handle a mixed audience of 20,000 dial-up and broadband users that would have required eight conventional servers.
Content owners "know that if they are going to do something popular in order to drive ad revenue, they are not going to make it up in volume if they are losing money on every transaction," Haines says. "So as soon as we walk in and say, 'It doesn't matter how many people are interested in the content. Your costs are fixed,' people get very, very interested in it."
While its technology may seem theoretical, privately held Digital Fountain has managed to attract some big-name backers, including Yahoo! Broadcast and investors Sony Corp., Cisco Systems, Texas Instruments and Adobe. Its two server products--one for streaming media and the other for downloads--will debut at the National Association of Broadcasters' convention later this month.
The timing may be great for NAB, but the company does face a steeper launch hill with the currently slowing economy. But Haines says the product will find traction among companies wanting to get a rein on the high cost of delivering media on the Web.
"I think a product which has as its message enabling a new business model that creates the opportunity to make money off the Internet ... we're being received very, very favorably," she says.
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