A winner has finally been declared in Hollywood’s high-definition DVD war. So why isn’t there more cheering?

In the 1980s, the triumph of VHS over Betamax helped develop the lucrative home entertainment market. DVDs, introduced in the 1990s, turned into an even bigger gold mine, accounting for roughly 60 percent of studio profits in recent years, analysts say. The entertainment giants have positioned high-definition DVDs as yet another blockbuster business.

But the victory of Sony’s new Blu-ray high-definition disc over a rival format, Toshiba’s HD DVD, masks a problem facing the studios: the overall decline of the DVD market. Domestic DVD sales fell 3.2 percent last year to $15.9 billion, according to Adams Media Research, the first annual drop in the medium’s history. Adams projects another decline in 2008, to $15.4 billion, and a similar dip for 2009.

So instead of celebrating the Blu-ray format  which remains a nascent business  the studios are scrambling to introduce an array of initiatives aimed at propping up the broader market. Some efforts, like the addition of new interactive features and changes in how DVDs are packaged and promoted, are intended to prevent further market erosion while nurturing Blu-ray.