Blu-ray shows no sign of slowing down, after leading high-definition movie sales since the beginning of 2007. According to sources cited by Video Business Online, consumers bought around 250,000 units of Blu-ray movies during the month, compared to the estimated 125,000 units of HD DVD movies.

“Every week it grows,” said Rich Marty, VP of new business development at Sony Pictures Home Entertainment. “It’s growing faster than DVD did. Each month it just looks more and more promising.”

The Departed was released simultaneously for both formats on Feb. 13, offering an informal opportunity to gauge customer preference for each format. The Best Picture winner had one of the highest first-week sales totals for either format, selling over 20,000 units on Blu-ray and 13,000 on HD DVD. Blu-ray’s lead in sales of The Departed cannot be completely attributed to a customer preference or an installed user base.

The sales may be skewed in favor of the Blu-ray version of the movie as it retails for about five dollars less than the HD DVD version. The reason for HD DVD’s higher price point is because of its combo format, which places a standard-definition DVD version on the flip side of the disc, allowing it to be played on industry-standard DVD players. Owners of both HD DVD and Blu-ray machines may have chosen the Blu-ray version of the movie simply because of price, and not because of technical differences between the formats.

Ken Graffeo of Universal Studios Home Entertainment, the only major studio to exclusively support HD DVD, tells onlookers to be skeptical of Blu-ray’s recent pull-ahead. “When they start talking about numbers, two-to-one, that’s really about the release schedule,” he said. “You can’t look at the last two months as a trend or as what the consumer wants to do in this format. It’s really an artificial, short time period.”

According to the source, 650,000 HD DVD discs have been sold since the format’s earlier debut compared to 675,000 Blu-ray discs sold since hitting the market.