Slo-Mo Scores

Thomson's LDK-6200 camera prepares for its biggest test: the Olympics

It's another sweltering day in Athens, and Mia Hamm, U.S. women's soccer Olympian, is dancing past defenders in search of an open shot at the goal. She sees her moment and cuts left. The goalie takes a hesitant step to her right. Then Hamm catches the goalie off guard and slams a shot into the upper right corner of the goal. The team takes another step toward gold. And NBC has another chance to play back the shot—in HD and slow-motion.

Last April, Thomson Grass Valley rolled out the LDK-6200 slow-motion camera system, and adherents stepped up, led by Alfacam. The Belgium-based provider of outside broadcast (OB) vehicles will have 16 LDK-6200s on hand for HD coverage of the Summer Games. It recently put the camera through its paces at the EuroCup soccer championships.

The EuroCup games were broadcast in HDTV to more than 40 cinemas throughout Europe. The reaction to watching a slow-motion replay shot in HD, with the extra resolution HD provides, is simple: The added capability won't just improve HDTV broadcasts; it will revolutionize them.

"Upconverted slow-motion replays were always the weakest point of HDTV coverage," says Alfacam CEO Gabriel Fehervari. "On the small screen, you can't tell the difference. But on a screen more than 50 inches big, the difference is amazing."

For Fehervari, one of the camera's biggest attractions has little to do with slow-motion. The camera has three outputs: One sends out a full-speed signal; the other two are involved in the slow-motion playback. Previous slow-motion camera systems could be used only for slow-motion playback. "There's a higher return on the investment," Fehervari says, "because we can use it for concerts and other key events at regular playback speed."

Alfacam was in detailed discussions with Thomson for about a year, and for good reason: Alfacam headquarters in Lint, Belgium, are only 48 miles from Thomson's plant in Breda. One of the things the two companies worked on was ensuring that it was operationally similar to an SD camera. On one point, the LDK-6200 exceeds SD operations: Signals can be sent more than 3,000 feet along triax cabling, something even SD slow-motion systems can't accomplish.

The system works by recording 100 frames per second; each of the two output channels involved in slow-motion playback record 50 frames each. The outputs are sent to a video server, such as the HD LSM-XT from sports-replay equipment maker EVS, which has found widespread use in OB vehicles. The 50 frames in each channel are then recombined into one 100-frame-per-second output.

"Our software recognizes that outputs are being used for slow- motion and creates a jigsaw puzzle on the disc," says EVS Marketing Manager Marcel Gross. "The frames are played back in a continuous, logically ordered stream."

According to Gross, the system cuts the recording capability of the server by about one-third. SD content is usually recorded at 30 Mbps (megabits per second), but the HD material is recorded at 100 Mbps. "Although the server frame is compatible with SD," he adds, "it requires an upgrade for HD."