DirecTV's HD Channel Expansion

Software powers MPEG-4 transmission at 1080p.
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EL SEGUNDO, CALIF. News Corp.'s DirecTV digital satellite service now broadcasts 130 channels of HDTV programming across the United States to its 17 million customers. To get there, the direct-to-home service introduced innovative approaches to enable HD transmissions, including interactive features which rely more on software than hardware.

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At the heart of DirecTV's new HDTV service is the Omnibus iTX software-based production and transmission solution backed by Harmonic's MPEG-4 Advanced Video Coding (H.264) video processing solutions. DirecTV also worked closely with Tandberg Television in developing the Emmy-winning MPEG-4 platform.

"We knew about three years ago that we had to select leading-edge technology that would not be obsolete in a few years," said Hanno Basse, vice president of broadcast systems engineering for DirecTV. "We selected the Omnibus iTX product for the rollout of our national HD offering because their software solution can perform all the broadcast automation and playout functions we need without a major investment in hardware."

AWAY FROM HARDWARE

According to Basse, "Ten years ago, the state-of-the industry was that you had to buy a dedicated piece of hardware for each different function, such as separate workstations for editing and graphics, a master control system, and a video server for play-out. You had all these different islands of functionality, and you needed a router to put it all together into an integrated system."

More recently, the industry has been shifting away from dedicated hardware to perform specific functions. "The new trend is using generic computer platforms with a high-level of software integration for all the functionality. Now the hardware platform has become a means to an end, which means hardware is not a significant cost factor any more. With all the main functions are in the software, you can quickly change the functionality of that system by changing the software."

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DirecTV's main equipment room (MER-3) By implementing a software-based solution, Omnibus gave DirecTV a "radically different way to do things that simplified our job enormously," Basse said. "Because all the functions are performed in one box, the HD system that originally would have taken us two years to build and integrate instead took less than nine months."

Omnibus has long specialized in building automation systems for broadcast hardware, said Ian Fletcher, chief technology officer for Omnibus. "We saw that automation solutions were getting increasingly complex and expensive, and the automation system had to integrate hardware from diverse manufacturers," he said. "So we decided about five years ago to develop a software-based system that could reproduce all the functions of master control, from editing and graphics to voiceovers to video servers to up- and down-conversion."

Consequently, Omnibus developed the proprietary iTX solution for a standard Hewlett-Packard server, said Fletcher. "All we have to do is add our I/O card to the HP server, and you get full automation for both SD and HD."

Fletcher recalls that DirecTV saw the early iTX solution about three years ago. "DirecTV was looking for an HD automation solution that would give it a market advantage," he said. "They knew that conventional hardware for digital SD was expensive, and they didn't want to do that again. They felt there had to be a better way."

iTX allowed DirecTV to launch multichannel HD operations at a low cost with a single box that reproduces the entire transmission chain, Fletcher said. iTX manages the entire ingest, content management and play-out process. It produces a "sophisticated output" using logos, stills, voiceovers, live events, graphics and 2D DVE moves for squeeze-and-tease effects, picture-in-picture, and other functions.

"iTX enabled DirecTV to move rapidly into HD transmission in a competitive marketplace," said Fletcher. "It gave them a path to easily pass through HD channels as well as affordably create new HD pay-per-view and video-on-demand channels. This can be done with just two to four rack units per transmission chain. Adding new channels is as easy as adding more rack units at a fraction of the cost for conventional hardware."

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DirecTV's transmit satellite antenna farm Fletcher said the iTX system is designed to be modular for scaling horizonally or vertically or both. "Every channel is a dedicated, self-contained software application with a playout function," he said. "You can add as many channels as you want so long as you have the network backend to support them. This flexibility lets you adapt as your needs change."

iTX ACROSS THE GLOBE

Omnibus so far has installed systems for more than 650 channels among about 30 customers in Europe, Asia and the Americas, including mobile TV and IPTV systems. Other U.S. customers using iTX to launch new services include Turner, CNN, CBS Mobile, and ABC Mobile.

Basse said DirecTV is using the iTX system to go beyond HDTV transmission to enable advanced interactive services on the HD channels. "We already provide a variety of interactive services in our digital programming, such as interactive weather," he said. "The iTX solution now makes these interactive services more scalable as we add new HD channels, and it's a lot easier to add interactive features to these channels."

The ease of adding channels impresses Basse. "All we have to do is add a pair of boxes in the rack. There's really no upper limit to how many channels we can add. Our only real limit is transponder capacity on the satellite."

The other feature that sold Basse is the ability of the iTX system to support 1080p transmission, a new feature that Omnibus announced at last month's IBC show in Amsterdam. "In the past, we would have had to revamp the whole system to support the highest quality of HD," he said. "Now we just call on that functionality within the box without having to touch the hardware once it's installed. This made upgrading to 1080p very low-risk for us. We didn't have to take apart the whole place to do it. We only had the software on one piece of equipment to deal with, and we didn't have to perturb anything else. What we needed was already there."

To support MPEG-4 AVC transmission of the HD signal at 1080p, DirecTV chose Harmonic's DiviCom Electra 7000 HD H.264 encoders and the ProStream 1000 real-time stream processing platform with DiviTrackIP statistical multiplexing. The Electra 7000 occupies only one unit of rack space for every four channels compressed.

"HD video at 1080p is the top of the food chain," said David Price, vice president for business development at Harmonic, based in Sunnyvale, Calif. "You cannot get any better than that."

Although there had been trials, experiments and demonstrations of 1080p, Price noted, DirecTV is the first to roll out 1080p systemwide with H.264 encoding. "DirecTV places great importance on picture quality, so now they offer the best video quality available to any subscriber in North America, whether on cable or satellite," he said.