By Katie Marsal

Published: 08:00 AM EST

Compounding troubles for the ailing HD DVD format, Best Buy and movie rental service Netflix both said on Monday that they would focus their attention on Blu-ray discs.

Netflix was first to take the initiative and said that it would no longer add HD DVDs to its movie library, instead stocking only Blu-ray movies in the foreseeable future. HD DVD titles will remain an option for subscribers to the monthly service for now, but will gradually phase out as older movies leave regular rotation.

Best Buy is adopting a similar policy, according to reports. The big-box outlet now says it will prefer Blu-ray in its stores as of early March and will give both playback devices as well as movie catalogs more prominent placement in its stores than their HD DVD equivalents. Floor staff will also recommend Blu-ray over its rival.

Reasons given for the change vary widely. Best Buy simply cites consumer demand; as significantly more shoppers are buying Blu-ray products. the retail chain has an obligation to give customers what they want, according to company chief executive Brian Dunn.

For its part, Netflix chief content officer Ted Sarandos argues that the decision will bring "clarity" to the Netflix lineup and should free the company to promote high-definition video as a whole, instead of asking customers to choose between similar but competing standards.

The turnovers at either company only add to existing difficulties for HD DVD, which first saw its fortunes turn at the very start of 2008 when Hollywood studio Warner Bros.announced Blu-ray exclusivity beginning in June. Warner's announcement left more than 70 percent of all high-definition movies as Blu-ray titles and pushed the HD DVD Promotional Group to abruptly cancel its keynote speech at the Consumer Electronics Show later in January. Toshiba followed suit by cutting HD DVD player prices in what analysts at Gartner dubbed "useless resistance" to a sea change in favor of Blu-ray.

The effect on Apple of HD DVD's accelerated decline is unclear. Even after the release of an updated Mac Pro last month and the company's Macworld San Francisco keynote speech, the Cupertino, Calif.-based Mac maker has not offered optical drives supporting either Blu-ray or HD DVD. However, the firm continues to be a member of the Blu-ray Disc Association.