Philly Launch Raises Technical Ante


Two "ingest" points. Twelve server farms. Thousands of set-top boxes. Those items are among the components that will the 1,200 hours of VOD content Comcast Cop. intends to make available to 500,000 greater Philadelphia homes.

What's next? More efficient storage and better metadata tracking is on the wish list of Mark Hess. As vice president of digital television at the MSO's cable unit, he oversees Comcast's VOD rollouts.

For technologists looking to the future, the question is, "How fast will we blow by 1,500 hours of content?" Once that happens, there will be a need for a more efficient balancing act among storage, transport and streams.

"You can't be buying bigger and bigger servers for all 12 headends," Hess said.

Popular content can be stored at the edge of the network, while offerings that aren't used as much can be maintained in one central location.

A second issue concerns how to handle on-the-fly content-management issues. There are also issues surrounding the national distribution of programming.

Different content will contain different metadata specifications, based on licensing arrangements. The metadata sets how often a program can be played, whether it can be encoded or stored, or if it's only encoded for limited use.

Hess said having content that's tagged with that metadata from its origination source will help simplify future VOD rollouts.

Comcast ingests content at two locations in the Philadelphia area. Receive devices from TVN Entertainment Corp. and N2Broadband are at both sites. N2 handles content from In Demand and Showtime Networks Inc., while TVN handles most nontransactional offerings, Hess said.

Comcast uses software from Imake to manage content fed to the SeaChange International Inc. servers, which are spread across 12 locations. SeaChange also handles the real-time encoding of content from NBC and Comcast SportsNet at those two main ingestion points, before sending it to the 12 servers.

The content is sent to the 12 servers via gigabit Ethernet, then on to the 500,000 homes, which spread from Trenton, N.J., to Philadelphia proper and nearby Bucks County, Pa.

"Ten percent simultaneous usage is what we built for, and we're not in any trouble there," Hess said.

Most of the system is Motorola-based — boxes come from the DCT-2000 and DCT-5100 product line — but portions of the rollout use gear from Scientific-Atlanta Inc. S-A gear is principally deployed in the former Garden State Cable properties in southern New Jersey.

The VOD rollouts in 19 other markets helped Hess prepare for Philadelphia.

"We learned a lot getting ready for Philadelphia, based on what activity and usage we saw with movies on-demand," he said. "We did a lot of testing using emulators. We spent time working with SeaChange."

The biggest challenge has been working through the little problems.

"The staff within SeaChange and Comcast at the field level have mastered managing the multitude of possible errors, whether the asset isn't there or something is wrong with the application, whatever," Hess said. "It's a lot of hard work, and we're learning this product as we go. It's about making sure you have the tools to troubleshoot, and to proactively know what's going on."