Mr. Rockwell served as the leader for Dolby's Advanced Technology Group, and was involved in the company's Dolby Vision display technology, according to 9to5Mac. He has also been a part of Dolby's home theater product designs, along with the company's mobile products.
Apple hired Tomlinson Holman, Lucasfilm's TXH sound system inventor, in 2011 for its own audio efforts. Adding Mr. Rockwell to the mix backs up the idea that Apple is serious about its music and audio plans.
With his display technology experience, Mr. Rockwell could be involved in improving how the content on our Macs, iPhones and iPads look, too. The company offers high resolution displays on some of its laptops, and on the Retina 5K iMac, although its Thunderbolt display is out of date and sorely in need of an upgrade.
Prior to his work at Dolby, Mr. Rockwell was CTO at the video and audio editing software company Avid. Apple could take advantage of that experience, too.
Apple isn't saying what Mr. Rockwell is working on, and his LinkedIn profile doesn't offer up any real hints, either. Considering what he did at Dolby, it seems reasonable to assume he'll be involved in Apple's future display and audio technology.