BY LAURA J. NELSON

LOS ANGELES TIMES

As the night grew darker, a cold wind whipped across the asphalt expanse of the vintage Rubidoux Drive-In Theatre in Riverside, Calif. A howling gust banged open the door to the snack bar, where hot dogs glistened on metal spits and the black-and-white linoleum floor gleamed.

Quentin Tarantino's "Django Unchained" flickered to life on the colossal screen--for an audience of eight cars.

This time of year is always slow at drive-in theaters, which have been struggling with declining attendance for decades. But it's not just cold weather that has made this a winter of discontent. The digital revolution is here, and that could mean lights out for many of the nation's 368 surviving drive-ins.

Hollywood is expected to stop distributing 35-millimeter film prints to all U.S. theaters later this year. The vast majority of indoor theaters--hardtops, in drive-in lingo--have already converted to digital projectors, but 90 percent of drive-ins have not, according to an industry trade group. Conversion costs of $70,000 or more per screen could be too expensive for many drive-ins.

The Rubidoux plans to convert to digital projection, but its owner says the switch will be a struggle for many others.

"There's been panic, definitely," Frank Huttinger said. "Ma-and-pop outfits, second- or third-generation places, are hesitant to put up all that money."

The drive-in market today is a shell of what it was in the late 1950s, when teens and big families in big cars found drive-ins a fun alternative to indoor theaters. At their peak, there were more than 4,000 drive-ins, accounting for 25 percent of the nation's movie screens. Today, that's down to 1.5 percent.

The drive-ins that survived have been doing better in the past decade, spurred partly by cost-conscious families who can see double features or first-run movies at half the price of hardtops, said National Association of Theatre Owners spokesman Patrick Corcoran.

For younger audiences, there's the chance to travel back in time.

In most of the country, drive-ins close for the winter. Some may not reopen this spring because of the high cost of digital conversion, said John Vincent Jr., the president of the United Drive-In Theatre Owners Association. He declined to speculate on the number that may close.