HOLLYWOOD — DVD numbers may be creeping downward, but the vampire pic “Twilight” shows that savvy marketing can help give life to a supposedly moribund format.

A common first-week yardstick used by studios is 20,000 units in sales per $1 million at the box office. That would put the expectation for “Twilight,” with a $191 million box office take, at 3.8 million units sold in its first week. The film’s 5.2 million units mean it performed more like a $260 million theatrical release.

Following the title’s release March 21, “Twilight” set one-day DVD sales records at key retailers including Wal-Mart and Borders, and sold 3.1 million units overall.

Summit says the pic ranks among the top five first-day DVD releases over the past two years, along with higher grossing pics like “Pirates of the Caribbean: At World’s End,” “The Dark Knight,” “Harry Potter and the Order of the Phoenix” and “Transformers.”

Summit home entertainment chief Steve Nickerson attributed the teen-oriented title’s success, in large part, to its Saturday release, noting that many retailers would not have staged midnight parties for a standard Tuesday release.

“These (fan) girls would rather have a community event,” Nickerson says. ” ‘Twilight’ is a lifestyle and it’s not just about purchasing a DVD.”

About 5,800 stores nationwide — including Blockbuster, Borders, Hot Topic, F.Y.E., Hastings Entertainment and Wal-Mart — stayed open past midnight to sell “Twilight” as soon as it became available.

Appearances by cast members including Rachelle Lefevre and Ashley Greene and director Catherine Hardwick helped draw crowds of more than 2,000 — largely screaming teenage girls — to retailers in Salt Lake City, Los Angeles and Dallas.

Summit gave various retailers special versions to get them excited about marketing the product. Wal-Mart, which is the only retailer to sell the $17 single disc without bonus features, said the title represented its largest consumer pre-order ever. The retailer staged midnight events in about 2,400 stores, with a fan-greeting filmed on the set of “Twilight’s” sequel, “New Moon,” broadcast exclusively through its in-store TV network.

Big box stores Best Buy and Target have first dibs on the Blu-ray edition until May 5.

Suzanne Ault contributed to this report.