Corona's biggest bragging point is the efficiency of its video codec, which promises to deliver high-definition video compression (up to 720 lines per inch) at 1/2 to 1/3 the bandwidth required by MPEG-2, according to Michael Aldridge, lead product manager of Microsoft's Windows Digital Media Division. Though it's content-dependent (video with more action requires more bandwidth), Aldridge said it can deliver the DVD-standard 480 lines per inch (lpi) with ease, meaning that in hard storage (rather than streaming) applications, Corona would let DVD manufacturers put more movies at 480lpi on a single DVD, or put higher-definition movies on standard consumer DVDs all without switching to blue-laser technology.
Therein lies the rub. Earlier this year, the DVD Forum agreed to pursue a blue-laser standard and continue using MPEG-2. While the forum—of which Microsoft is a member—hasn't rejected Corona outright, it hasn't exactly embraced it either. "We've been developing a DVD-related format using MPEG-2 and some public open technology," said DVD Forum secretariat Hideyuki Irie. "Our policy is to keep standardization as open as possible. Currently, we don't have interest in adopting a new format other than the MPEG standard."
May saw nine DVD heavyweights (including Philips, Pioneer, and Sony) announce that they'd begin licensing their so-called "Blu-ray" disc—which holds 27GB of data on a 12cm disc—in June, so manufacturers have yet to jump on the more-bang-for-your-byte codec. But rather than seeing the blue-laser shift as a hindrance, Microsoft sees it as an opportunity. "It's more efficient than both MPEG-4 and MPEG-2 without blue laser, but we can work within blue laser. It's not an either/or situation," Aldridge said. "If you do use blue laser, the story gets that much better. Instead of putting three movies on a DVD, you'll be able to put six movies on."
Besides, it's not as if Windows Media isn't getting any support from the DVD community. Panasonic and Apex have released new players that support Windows Audio, and a group of chip makers including Cirrus Logic, ESS Technology, and LSI Logic announced that they'd add support for Windows Media, including Corona, this year.
One of the advantages that Corona has over MPEG-4, Aldridge said, is that it's backwards compatible: while the encoding compression changes, the decode technology stays the same. So any consumer devices already Windows Media-compatible will be able to handle most of Corona's technology. The only exception to that is Corona's support for 128Kbps six-channel surround sound audio, Aldridge said.
In fact, it's still Corona's non-DVD applications that have Microsoft most excited. Its Fast Stream technology offers "instant-on, always-on" viewing and listening, which means no buffering delays for HDTV-quality video over the Web, Aldridge said. And Corona holds promise for hard-storage audio applications, too. The new Windows Media Audio format will allow more than 22 hours of music to fit on a single CD. Corona will also offer a set of developer tools for software developers to incorporate the technology into their projects; software giants like Adobe, Avid, and Creative Labs already have announced their support.
Corona already is scheduled for beta testing late this summer, with a final release set for later this year. Aldridge wouldn't make any predictions as to whether or not the DVD Forum could be swayed to adopt Corona, or whether it will prefer to keep its options more open. "There's always challenges when introducing any new technology," he mused. "That'll just be up to the industry and the Forum."