The backers of the Blu-ray high definition DVD system have received a twin boost in their format war with HD DVD, with Best Buy and Netflix to declare support for Sony's format.

Best Buy - the US's largest consumer electronics chain - has announced it is to recommend that its customers choose Sony's Blu-ray format. Its shops will carry HD DVD but Blu-ray will be displayed more prominently.

"Because we believe that Blu-ray is fast emerging as that single format, we have decided to focus on Blu-ray products," Brian Dunn, Best Buy's president and chief operating officer, said in a statement.

Best Buy will prominently feature Blu-ray hardware and software beginning in March, but will also carry an assortment of HD DVD products for customers who want those, Best Buy said.

And online video rental company Netflix said it would phase out its HD DVD stock and exclusively offer Blu-ray, citing the decision by four of the six major movie studios to publish high-def DVD titles only in Blu-ray format.

"The prolonged period of competition between two formats has prevented clear communication to the consumer regarding the richness of the high-def experience versus standard definition," said Ted Sarandos, chief content officer for Netflix. "We're now at the point where the industry can pursue the migration to a single format, bring clarity to the consumer and accelerate the adoption of high-def. Going forward, we expect that all of the studios will publish in the Blu-ray format and that the price points of high-def DVD players will come down significantly. These factors could well lead to another decade of disc-based movie watching as the consumer's preferred means."

Toshiba described the decisions as "unfortunate" and will study the market impact.

Both decisions give Sony yet another victory in the battle with Toshiba's HD DVD high-definition DVD format.