Long-Form via Pathfire

Pathfire recently traveled the long road toward long-form content distribution, and it's already reaping the benefits. Warner Bros. Domestic Television is using the system to distribute syndicated programming to broadcast stations in the U.S. and Canada.

"Our view is that file-based delivery of product in either a linear fashion or in a non-linear fashion with IP-based technologies like Pathfire represent the basis for next-generation distribution," says Darcy Antonellis, Warner Bros. senior vice president of distribution technologies and technical operations.

Antonellis says the first show distributed via Pathfire had a file delivery success rate of 93%. Warner Bros. syndicated programming is distributed to more than 600 stations and more than 95% of those are using the Pathfire system now.

The Pathfire system packets the content using Internet Protocol (IP) and sends the video as data files. The files are reconstituted at the station's receive server to create the original and complete audio and video content file.

"One advantage is that stations will now have frame-accurate timing information with the program," says Mike Carey, Pathfire senior vice president of marketing. "That saves a lot of time at the station because they won't need to worry about making sure the ins and outs for commercials are right."

Programs that will be distributed with the system include ER, Friends, Will & Grace and The Drew Carey Show.

The move required reengineering to enable the Pathfire transport system to handle long-form content, including two-hour movies and even HD content. "When we first started distributing content several years ago," says Pathfire Senior Vice President, Broadcast, Floyd Christofferson, "we realized that, once we got above 150 sites, the statistical packet loss that aggregates across multiple sites compounds when you get more sites and longer-form content."

Issues of packet loss are compounded, he adds, when "nack" collisions occur. Nack stands for "negative acknowledgement," a message sent from the receive server at the station back to Pathfire when a packet doesn't arrive properly. The Pathfire system then resends the packet.

The problem that Pathfire needed to solve was how to deal with the number of nacks that occur when long-form content is distributed. If 1,000 receive servers were to send back nacks simultaneously, the buffer on the Pathfire server could be overwhelmed and become very inefficient. Pathfire solved the problem with a combination of randomization of the incoming messages and adjusting how the servers deal with nack issues.

"Long-form delivery is the kind of thing stations don't notice because it's underneath the hood, but it allowed us to differentiate ourselves from the competition," Christofferson notes. "It's all about finding the right balance between forward error correction and nacking, getting reliable delivery, and still gaining the bandwidth benefits of store and forward."