Marion Barry wanted to go on TV live, to announce his long-awaited plan for solving the city's budget crisis on television direct from his white-carpeted executive office on the top floor of the District Building at 7:30 p.m. July 21. So the mayor dispatched his press envoy to ask for 15 minutes of air time.

A live broadcast would be expensive, the station officials told press secretary Alan Grip, and apparently the mayor's speech wasn't worth it. So Barry settled for a compromise arrangement. He will tape the speech early that morning for broadcast that night on three Washington stations. It was the most economical way, all agreed, to handle such a momentous event.

"This is a matter of such importance to the citizens of the community that it's akin to when the president wants to talk to the country about a matter of importance," said Edwin W. Pfeiffer, vice president and general manager of station WDVM (Channel 9).

John Rohrbeck, general manager of WRC (Channel 4), said his station plans to have anchormen Jim Vance and Marty Levine analyze the budget message after the 7:30 broadcast. He said station officials "felt we had a responsibility" to carry the speech.

On the other hand, Armand Asselin, news director of WTTG (Channel 5) said a "programming decision" was made to stick with M*A*S*H and not carry the speech. "We intend to cover it fully on the news," Asselin said.

Taped or not, the mayor's budget plans are being announced to the city in a media extravaganza of the kind usually reserved for presidents and prime ministers. President Carter, for example, went on television live at 7 a.m. April 25 to formally announce the aborted hostage rescue mission in Iran.

But the format is not unique in Washington politics. During last year's 23-day teachers' strike, Barry asked for live access to the major local TV stations when he went on television to ask the City Council for power to settle the strike.

The budget crisis is the worst in the city's history, and Grip called the address "the most important [Barry] will probably give" in his administration. For nearly two months now, Barry has responded to questions about the crisis largely by saying that they would be answered in July 21 proposals.

Grip said the seriousness of the budget problem -- which includes an accumulated deficit of $284 million and a deficit for the current fiscal year of up to $170 million -- is the reason for the elaborate broadcast arrangements.

But the broadcast, to be carried by WRC (4), WJLA (7) and WDVM (9), also effectively allows Barry to bypass the press and speak directly to District residents, Barry's relations with the press have been stormy in recent months, culminating in his decision several weeks ago to shut down his personal press office.

Grip said yesterday that several radio stations have decided to carry the speech simultaneously with the television broadcast.The list of radio stations is not yet final, he said.

Representatives from WJLA visited Barry's office yesterday to decide where cameras would be placed. WJLA will provide a "pool" crew for the speech, which will tape it for transmission by all three stations.

Tentative plans call for two cameras -- one to frame a head-on shot of the mayor behind his desk, the other to focus on charts and graphs Barry intends to use in the presentation.

Grip said he plans to set up television monitors in the mayor's conference room so reporters can watch the broadcasts, but reporters will not be allowed to ask questions of the mayor after the speech.

Other city officials, including City Administrator Elijah B. Rogers, Budget Director Gladys W. Mack and Finance Director Carolyn L. Smith, will be on hand.

A briefing for members of the City Council had been scheduled for earlier in the day.

Charts and graphs accompanying the speech will be drawn up by employes of the city administrator's office, Grip said. Barry said he will not write his speech, but declined to say who will.

What happens if the speech does not provide the kind of news the television and radio stations are banking on, one television executive was asked. "Then I guess we're stuck with what we get," said WDVM's Pfeiffer.