Sales of Barnes & Noble Inc. Nook tablets, e-readers, digital content and accessories decreased 12.6% to $311 million in the nine-week holiday period ending Dec. 29 compared to the same period in 2011, Barnes & Noble says. Barnes & Noble had overall revenues of $1.2 billion in the period, including its stores and e-commerce site. It will report its third quarter results Feb. 19.

Sales declined despite the release in 2012 of two tablets, Nook HD and Nook HD+, which Barnes & Noble sells along with its two Nook e-readers. Barnes & Noble is No. 32 in the Internet Retailer Top 500 guide.

But when separated into Nook devices and digital content, a bright spot emerges. Nook digital content sales, including digital books and publication, and apps, increased 13.1% in the holiday period. Nook device sales failed to sell as well as expected, Barnes & Noble says.

“Nook device sales got off to a good start over the Black Friday period, but then fell short of expectations for the balance of the holiday,” says William Lynch, CEO. “We are examining the root cause of the December shortfall in sales, and will adjust our strategies accordingly going forward.”

In August, Barnes & Noble lowered the prices on some Nook devices following the release of the Nexus 7 tablet from Google Inc. earlier in the summer.

Barnes & Noble has been bolstering its Nook digital strategy with the formation last year of Nook Media LLC, a joint venture with Microsoft Corp., for managing digital content on Nook devices. In December, international publishing firm Pearson PLC invested $89.5 million in Nook Media to become the third partner.

Revenue from Barnes & Noble’s retail segment, consisting of its e-commerce site and its bricks-and-mortar stores, decreased 10.9% to $1.2 billion in the 2012 holiday season compared with the 2011 holiday season. Barnes & Noble attributed the decrease to an 8.2% decrease in comparable-store sales, store closures and lower online sales. Lower volume and average selling prices affected Nook sales, the retailer says.