When television producer Tony Brown arrives to discuss his current four-part series on black sacred music, he is carrying two suitcases, one briefcase and whatever words and energy are left over from the 35 speeches he is giving in this 28-day month.

This demand for his message and ideas, and his energy, contribute strongly to the longevity of "Tony Brown's Journal," a weekly program that is the oldest black public affairs television show. In 1968 the program debuted as "Black Journal" and Brown became host and producer in 1970.

"Its staying power can be attributed to a combination of facts," he says, taking time to discuss his film projects between a speech at the General Accounting Office and the National Aeronautics & Space Administration. "Blacks are a stronger community than blacks suspect. And white folks know that. Then there has been a tremendous growth in our white viewers. We know 60 percent are white. I remember a time we didn't have two whites watching."

"Journal" now has an audience of 4.5 million. It is aired in 115 markets and is financed by the Pepsi-Cola Co., which last year gave $2 million to the show.

This year, Brown, 46, who was the first dean of Howard University's School of Communications, is taking a new and pioneering step. "Thank God!," a four-part documentary series he directed on the black religious music that has emerged from the fields and sanctuaries of worship, is currently being shown on the Public Broadcasting System. After its initial television showings, Brown will release the footage, and two other specials, to black organizations as fund-raising vehicles. He announced this ambitious plan last month to create alternative movie products and distribution. "This puts us into the movie business on our own terms and at a profit," says Brown.

Brown describes the format of "Thank God!," his first directing effort, as a "docu-opera." "The only indigenous American music is music which took the form of the old Negro spirituals and evolved into blues and jazz and other modern music," says Brown. In the show, the plot is sung, accompanied by spoken narration from Brown and Rev. Wyatt Tee Walker, an authority on black sacred music. "While we were dubbing, an editor said this feels like an opera. At times it reminded me of 'Oklahoma' or 'Porgy and Bess,' " says Brown.

Part two of the series will be shown on WETA (Channel 26) at 10:30 p.m. tonight and on WHMM (Channel 32) at 8 p.m. Sunday. In this segment, the history has moved forward from the African villages to the American fields and hollows, where the slaves meshed their oral traditions with the Christian faith. In these "invisible churches," the slaves not only worshiped but also devised spirituals that were used as communication. The a cappella singing of "Didn't My Lord Deliver Daniel" is strong and joyous. The installment ends with the establishment of the African Methodist Episcopal Church in the early 1800s and the publication of the first book of spirituals.

This film is distributed to black groups along with "The Longest Struggle," a history of the NAACP, and "America's Black Eagles," the story of the Tuskegee Airmen of World War II, which were created as Black History Month specials.

"We are letting blacks tell their own story and creating a market for alternative films," says Brown. His production company modifies the film to 90 minutes and then charges the renters.

"It cost $100,000 to convert the television film to one print," says Brown. "And if the group makes $20,000, then we would receive about $3,000. We want the groups to make money."

Initially the distribution is aimed at the 450,000 members of the NAACP, the 20 million members of the 60,000 black churches in America, and veterans groups. The one strong caveat in Brown's distribution system is that an underwriter of an event planned around the screening not be a competitor of Pepsi.

Brown thinks the black audience wants movies with black themes. "The story of the NAACP is going to be viable 100 years from now. Hollywood is not interested in those topics because they think they aren't economically feasible."

Brown plans to start producing feature films this year. "They will resemble the old race movies, themes that blacks are interested in. It will be easy to do three in a year. And the product is needed for cable television and home video viewing. I am not interested in being plugged into the Hollywood system as it is now," he says.