The television cameras were rolling. The Cardozo High School Band, came strutting across the street and managed a smooth musical transition from the "Battle Hymm of the Republic" to Michael Jackson's feverish tune "Beat It."

The city's premier high school band had been picked to greet the "Real People" television show cast at Union Station last week, and they were showing off for a future national television audience.

The band that raised hometown pride when its members traveled to Pasadena, Calif., for the Tournament of Roses Parade in 1981 had assumed after that triumph that its brush with national recognition would be fleeting. But that has not been the case. The Cardozo band is still wearing out the soles of its marching shoes for audiences far removed from its Clifton Street NW home base. And it still holds the admiration of fans and followers here.

Just a week into the current school year, the 100-piece band was in New York City to perform at the National Afro-American Day Parade. Marching sometimes twice a day, the band has performed 40 times this year, band director Richard Gill said. Cardozo's band played "The Lone Ranger" theme in a Ford pickup truck commercial last spring.

The band's White House debut is set for June for the 15th anniversary of the Special Olympics, and the Cardozo band will be featured in the movie "D.C. Cab" being filmed in Washington.

"After the Rose Bowl Parade, I figured all the excitement was over and we could relax," said Stuart Goins, a 17-year-old senior and a trumpet player. "Then someone calls us up for something equally important. It makes me feel very, very important, like something you can only dream about."

The "Real People" cast was in town for the finale of its national whistle stop train tour and the event, along with the band's performance, will be aired on NBC this fall, a "Real People" spokesman said.

When the public relations firm of Hager, Sharp and Abramson began the "Washington is a Capital City" campaign last year, three Cardozo band members were picked to appear on the campaign's main poster. The same firm picked Cardozo to greet "Real People."

"They are terrific. We thought, my gosh, the band has to be there for the welcoming of 'Real People.' They're very tight, very professional and they represent our city well," said Susan Stockdale, project coordinator for the promotional campaign.

Success apparently has not gone to their heads. Almeta McCall, mother of sophomore trumpet player Jeffrey McCall, 17, remembered when her only son walked home one day and told her about the movie scene.

"He was so casual about it. I think it's unbelievable," said McCall, a volunteer who works with abused children. "I was lifted to my heights by it. I would never have dreamed that any member of my family would be doing this."

The band was scheduled to march past the District Building yesterday for one of the later scenes of the movie. When Gill told some of his charges about the band scenes last week, there were more groans than excitement about having to be ready to march at 6 a.m., and some band members were initially concerned about maintaining the band's crisp, yet rhythmic style.

"There are three band scenes," Gill explained. "The first two are where we just can't get ourselves together. We're all disorganized. We're not together at all. People are leaving practice."

"Disorganized? Us?!?," asked Goins, Cardozo's ROTC cadet commander. Then Gill explained that the first two scenes were being played by Californians and that the real Cardozo band scene, with the students suddenly transformed into flamboyant precision, would be acted out in yesterday's march past the District Building.

"In other words," said Gill with a wry grin, "we get to play ourselves."

Gill's brother Robert led the band for 10 years before Richard took over two years ago. "I had worked with most of the kids before," said the 33-year-old Gill, who also teaches instrumental music at Cardozo. "Everyone thought this would make the smoothest transition."

One day last week the stage version of the band worked on sharpening up with some jazz licks of Donald Byrd's "Fancy Free" and Marty Gold's "Jazz for Jackie," amidst faded sea-green paint that is peeling from the walls of the school, once called the "Castle on the Hill" because of its panoramic view of downtown Washington.

A poor and sometimes crime-ridden neighborhood surrounds the building, but the band holds a special prominence here. Young school children wander into the building and climb the three floors to the band's indoor practice room just to stand and listen to them run through everything from Chuck Mangione's "Land of Make Believe" to the theme from "Dallas."

"I like to hear 'em play," said 7-year-old Raymond Jennings, offering his best Grover Washington Jr. impression with an imaginary saxophone. "I want to play for this band when I grow up."

James Foster is 70 years old and a 1933 graduate of Cardozo High School who can't wait to come down and help out with the band, leading them whenever Gill can't make an engagement.

"They're an inspiration, something to keep me going rather than just sitting on my porch and deteriorating," Foster said.

Every member has to maintain a C average to stay in the band, and sometimes they practice three hours a day, even on weekends and on vacations, but no one seems to mind.

"I have experienced and learned a lot," said Jacqueline Britt, a 17-year-old senior clarinet player with the band. "It makes me feel very good to be a part of this band."

The makers of "D.C. Cab" have talked about sending the school $1,700 for the band's participation, Gill said. A check expected from Ford for the commercial hasn't arrived yet, he added.

But the band receives nothing for most of its appearances. For playing in the Apple Blossom Parade in Winchester, Va., and in Washington's Cherry Blossom Parade, the band had to pay fees ranging from $100 to $150.

Gill said that doesn't matter. "This is Hollywood," he said, referring to the movie appearance. "This is the real thing."