File-based delivery
Dec 1, 2008 12:00 PM, By Brad Gilmer
Thanks to technical advances and falling prices for bandwidth, file-based content delivery is more common.
One-way IP transmission
Because of the unavailability and high cost of connectivity, satellite transmission can still be the best way to reach some facilities. For file-based distribution, engineers came up with clever ways to modify existing IP technologies. IP was designed assuming that there would be a two-way conversation between the sender and the receiver. The predominant method of error recovery in IP requires that the receiver notify the sender that a packet has been lost so that the sender can retransmit the lost information. Without a return path, this and many other protocols designed to work over IP will fail. A few smart people have figured out how to make file-based delivery work using IP either without a return path or with a low-speed return path. Without these modifications, file-based delivery of content using IP would be impossible.
Large-scale fiber deployments
Over the last 15 years, the telecom industry has laid tens of thousands, perhaps hundreds of thousands, of miles of fiber-optic cables. No one knows exactly how much; the carriers keep this a closely guarded secret. At this point, fiber passes by most homes and businesses in metropolitan areas, and fiber is installed in all major league and most college sports venues. Some, but not all, last-mile problems have been solved by a massive investment in fiber by the telecom industry.
File-based delivery
File-based content delivery is increasing. Of course, when you consider the effective bandwidth of an overnight courier truck loaded with tapes, it is difficult to beat. Even so, demand for file-based delivery is growing.
There are several factors driving this. First, file-based delivery allows just-in-time delivery of content. For example, if an advertiser wants to change a commercial, it can do so closer to air using file-based delivery technology. Second, there are costs associated with filling the overnight courier truck with tape that go beyond the shipping costs. The costs associated with a national tape duplication facility are significant. Finally, depending on the technology used, file-based content delivery ensures that the copy created at a broadcaster's facility is either a bit-perfect copy of the original, or it does not arrive at all. This eliminates tapes that are rejected for duplication-related technical errors.
File-based content delivery is not a panacea. Traditional delivery mechanisms will probably coexist with file-based delivery for quite some time. But the technical advances described in this article coupled with falling prices for bandwidth mean that file-based content delivery is here to stay.
Brad Gilmer is executive director of the Video Services Forum, executive director of the Advanced Media Workflow Association and president of Gilmer & Associates.
Send questions and comments to: brad.gilmer@penton.com
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