"Starsky and Hutch," one of the 20 most popular shows on network TV and, according to a recent study, the most violent show on network TV as well, is about to get an overhaul. Aaron Spelling, one of the executive producers of the series, says that as a result of the escalating campaign against TV violence, Starsky and Hutch are going to clean up their act.

"We are going to take the violence out of 'Starsky and Hutch,'" said Spelling from his Hollywood office. "I promise. We're going to stop it. Period. And if the rating slips two points, then the rating slips two points."

"Starsky and Hutch" without violence? That sounds like Lawrence Welk without shmaltz. "Starsky" is the series about two bullying buddy cops that began the season with an episode called "Stranglers in Paradise" and had a later installment advertised on ABC with the come-on, "Saturday - Starsky and Hutch face a bloodbath at the hands of a deadly cult!"

But things are changing in television. Hollywood and the networks are running scared. After a 25-year war on TV violence that has remained a virtual stalemate, the antiviolence forces are making dramatic inroads. They are wresting promises from producers, networks and sponsors to cut down on the televised mayhem that many experts believe contributes to actual violence in American society and distorts the world view of youngsters who will have seen an estimated 13,000 televised murders by the time they are 15 years old.

Congressional studies on TV violence go as far back as 1954 and have continued like clockwork, largely without effect. The Surgeon General's Office issued a landmark report on the topic in 1972, but if anything, prime-time television grew subsequently more violent, not less.

This year, pressure groups have taken aim at the broadcasters' most vulnerable spot - their money belts. The National Citizens Committee for Broadcasting (NCCB) published a list of the "most violent" shows and the sponsors who advertised on them, totalling up violent acts and defining them as "aggressive personal incidents of violence which clearly and intentionally threatened personal injury in a serious way." The five shows found most violent: "The $6 Million Man," "Hawaii Five-O," "Baa Baa Black Sheep," "aretta," and "Starsky and Hutch." Joining the Fray

Then the American Medical Association (AMA), which supported the NCCB survey with a $25,000 grant, urged sponsors to drop out of shows that rated high on the violence scale. Other groups joined the bandwagon. The National Parent-Teacher Association is holding another of its regional TV violence conferences in Los Angeles today. Groups as diverse as the Southern Baptist Convention and the Screen Actors Guild joined in the antiviolence clamor.

The means of assault aren't limited to rhetoric. The Church of the Brethren not only opposes TV violence, it owns stock in one of TV's largest advertisers, Procter and Gamble, and is trying to influence the company's ad buys from the inside.

Opposition to TV violence, and a willingness to fight it at the supermarket level, aren't limited to do-gooder groups, either. In a Gallup Poll to be released this week, a majority of parents questioned said they believe there is a direct link between televised violence and rising crime in the streets.

While the majority said they wouldn't favor a boycott of sponsors whose commercials appear on violent show, one-third of those polled said they would support such a boycott. The word "boycott" may not exactly strike terror into Madison Avenue, but it is good for a couple of extra Alka-Seltzers after lunch.

NCCB president Nicholas Johnson, a former FCC commissioner, hasn't advocated boycotts yet."We've been very careful about that," says Johnson. "We haven't urged people to boycott but then, in all candor, when you publish the names of the most violent sponsors, you don't need to."

There is evidence that the business community is not taking the boycott threat lightly. The J. Walter Thompson advertising agency, one of the nation's three largest, came out with an antiviolence warning to advertisers last June, suggesting that advertising on violent shows could be very bad public relations. This week the company published a survey of consumer opinion which indicates heavy viewer opposition to continuing TV violence.

Of those survey, 47 per cent said they felt TV programming had "gotten worse lately," and of that group, 32 per cent volunteered as the reason "too much violence." Another 26 per cent said the reason was too many crime shows.

The survey, to be distributed to Thompson clients, ends with some crucial conclusions for advertisers, including this one: "There is a danger that products advertised on violent programs may be boycotted by small, but vocal and growing numbers of people."

Johnson says public arousal over TV violence is growing and says the NCCB sent out more than 12,000 copies of its violence rankings after Ann Landers mentioned the group in her syndicated column. "The point is," says Johnson, "this means that the media reform movement has now moved into the mainstream of American society." The Networks React

The networks are reacting - there's no doubt about it. The National Association of Broadcasters (NAB), which endorsed the fizzled Family Hour plan - later ruled unconstitutional in court - is now at work rewriting its broadcasters code to stiffen strictures against violence. Not all stations subscribe to the code, but the three networks do.

NBC, which initially denounced the NCCB study when it found NBC the "most violent network," became the first network to proclaim a housecleaning. NBC-TV president Robert T. Howard issued a statement earlier this month conceding that "the proliferation of program types whose plot lines heavily involve violence has become excessive."

As a result, Howard told NBC affiliates in Miami, NBC is going to veer away from "the hard action form" next season, with "nearly half" its proposed new shows to be in the "comedy and variety fields."

Frederick S. Pierce, president of the ABC television network, flew into Hollywood last week, according to Spelling, with an edict for program producers: "No more violence.Period. Period. Period." The remodeling may be apparent sooner than next season. Insiders say ABC is now toning down the violence in the new series "Dog and Cat" which is to premiere early next month.

"The networks have heard the signal," says Gene Secunda, spokesman for the Thompson agency."There will be lots of changes next fall; the de-escalation program is already in progress, and companies are moving further and further away from wanting to sponsor violent shows."

In Hollywood, Steve Cannell, who created "Baretta" and is now executive producer of "Baa Baa Black Sheep" and "The Rockford Files," says, "There is incredible pressure on right now to eliminate violence from scripts. The problem has suddenly become a terribly hot political football. There's more pressure now than there has been in years."

Freelancer David Taylor, who has sold scripts to "Kojak," "Switch," and other crime shows, says writers are also becoming sensitized to the new violence scare. "The networks are telling producers, 'We're trying to get away from violence because we're afraid of losing advertisers,'" Taylor says. Spot Ad Sales

But how much influence can sponsors actually exert over the contents of a program? In the '50s, many TV shows had only one sponsor; Perry Como and Dinah Shore were "brought to you by" single companies or products. Now, most of television is given over to "spot sales," so that one program can include ads for many different companies.

Ken Lane, media buyer for the Leo Burnett ad agency - the country's second largest, according to The Wall Street Journal - says sponsors have limited control over where commercials appear.

"The networks sell time periods, not programs," says Lane, "and even if you know what program is in the time period, you have no idea what episode your ad will be on. It could be a very violent one or a nonviolent one. Sponsors have no say at all in terms of episodes."

In addition, says Lane, network prime time sells out so fast that many sponsors participate heavily in "up-front buying," which means signing 52-week contracts in the spring, long before the fall season starts and the network schedules are definite. And when advertisers buy time in network movies, they usually have no idea what the movie will be - whether their ad will pop up in the middle of "Rollerball" or "The Sunshine Boys." Affiliates Use Clout

But Johnson says that if enough companies tell their ad agencies not to buy time on violent shows, their combined clout can substantially change TV content. And increasing numbers of advertisers are making such directives. Broadcasting Magazine headlined a recent report on the trend, "Networks think it's for real as advertisers scramble for antiviolence bandwagon."

"It's becoming the issue of the day," says Secunda. "All of our clients are sensitized to it. Nobody I know is resisting the idea."

Networks are also hearing about excessive violence from their affiliates. ABC has had troubles this season getting all of its stations to carry such lurid and violent TV movies as "Nightmare in Badham County." Recently CBS affiliate WMAR-TV in Baltimore not only refused to air the network movie "A Man Called Horse" but told its viewers it made the decision because of "excessive violence in the movie scheduled to be shown." Kick-Me Toy

The station substituted "Guess Who's Coming to Dinner" and, according to general manager Dale Wright, got 720 phone calls protesting its decision and only 22 supporting it. "People who are mad at you are always more likely to call than people who are happy with you," says Wright. He thinks the network demonstrated "insentivity" by scheduling "Horse" for 9 p.m., when many children are still watching TV.

It's been said, of course, that opposing violence is like supporting motherhood; nobody is calling for more shootings and rapings on television. Yet there is another side to the violencer issue and to the current retreat by sponsors from violent shows.

"I agree there's too much violence," says producer Spelling, "but I just hope to God this doesn't mean we're going to turn all of television into pap, that we're going to be stampeded by the pressure groups into making all of television for children.

'We don't want television to become some kind of candyland, some kind of fairyland. That's terribly, terribly dangerous. You simply can't say we will have no more violence on television. 'Roots' was a very violent show; does that mean we shouldn't have done Roots'?"

Television has always been "a marvelous kick-me toy for anybody who wants to get press," Spelling notes, and producer Cannell is also skeptical about some media reformers. "That Johnson thing is bull," he says. "It's not a very responsible thing at all, and it doesn't help the networks, to deal with this issue in a sensitive way. When Johnson claims that a Western about a 19th-century schoolmarm ('just laugh. But he gets the headlines." Backlash Effect ust laugh. But he gets the headline." Backlash Effect

Broadcast historians know that the more closely sponsors can control program content, the less likely it is that daring or controversial subjects will be dealt with on television; the new sponsor awareness could have a backlash effect recalling the days when President Abraham Lincoln's last name was deleted from a TV script because a competing auto firm didn't want "Lincoln" to get a plug.

It would be difficult to find anybody in television, however, to defend the violent status quo. And there is no question that networks have authorized the use of violence as a gimmick to snare viewers. "No network executive ever said 'We need more violence per se in that script,' " notes Spelling, "but I have had them say, 'We need more action.'"STAction" is the TV industry euphemism for "violence."

"When you submit a story synopsis to a producer, he submits it to the network for initial approval," says writer Taylor. "It's at that point that the network can say, 'We need more action' or 'We need less action.' Except that I've never heard them say, 'We need less action.'=

But less action is just what viewers are going to get. "We're never going to kill anybody," promises Spelling, "unless it's totally essential."