The broadcast networks would seem to be gliding through the writers’ strike, now in its 12th week, with virtually no ill effect on primetime.

But that doesn't mean viewers are oblivious to the walkout by TV and movie writers.

A recent study suggests the networks are already losing viewers to cable television, DVDs, videogames and other entertainment, or soon will.

The study, by Interpret, a media consultancy, found that more than one out of four TV viewers said they were watching less TV than before the strike. The survey, which was done online, polled 1,000 adults 18-49.

That one-in-four figure is probably inflated. Overall TV viewing is actually up over last season, and ratings in key demographics are only slightly down. But in the minds of media researchers, the results clearly point to a souring attitude among viewers as they tire of repeats.

And if that's indeed the case, they suggest steep ratings declines are likely to follow.

Certainly some of that souring could be a carryover from the holidays, when network schedules are notably heavy with reruns. With the midseason now underway, schedules have been refreshed with new series and fresh episodes of returning shows.

Yet a lot of the top shows are in repeats, with no new episodes in the pipeline, and that will have an impact, say researchers.

“At a certain point, people are not going to turn on the established broadcast networks,” says David Scardino, entertainment specialist at Rubin Postaer & Associates in Santa Monica, Calif. “They will not be looking there for their entertainment. That’s inevitable.”

Most worrisome to the networks, it's the heavy TV viewers, those who watch more than 21 hours each week, who appear to be most annoyed by the strike. A full third said they were watching less TV than before the strike. That's not surprising. They are the viewers who would first notice and be irked by repeats of shows like ABC’s “Grey’s Anatomy” and NBC’s “Office.”

“In a prolonged strike, if these shows don’t come back, the ratings by May will start to look like [summer] ratings,” says Shari Anne Brill, senior vice president and director of programming at Carat.

Scardino agrees, saying, “If the strike goes on, then I think all bets are off. I think we could be into double-digit erosion.”

That's consistent with forecasts, such as one from Magna Global, which foresees only modest declines for January and February, around 5 percent among 18-49s, but declines of 13 percent if the strike goes on into May.

One interesting finding of the survey was that while viewers may be souring over reruns, they're clearly not blaming the writers. Viewers continue to side with the writers and against the studios.

Of those surveyed by Interpret, 94 percent were aware there is a strike and more than half said they were familiar with the details of the strike. Of these people, 56 percent sided with writers. Only 7 percent sided with producers. The rest took neither side.

So much are they siding with the writers that many said they would not watch the Academy Awards this year if the strike continues. Just over one-fourth who watched last year said they would not watch this year in support of the writers.