CarPlay represents an ambitious leap for Apple into a fragmented landscape dominated by proprietary technologies and processes. The company must find a way to meld hundreds of different control layouts featuring multiple combinations of knobs, buttons, and touchscreens with what has traditionally been a system centered on a single pane of glass.
One way for Apple to cut through the muck may be to adapt a familiar, flexible tool that has already been adopted by dozens of third-party manufacturers for the task: AirPlay.
While Apple has been characteristically tight-lipped about CarPlay's technical details, admitting only that the feature will require a Lightning-equipped iPhone at launch, its automotive partners have been more forthcoming.
Data from the iPhone's display is sent to the vehicle's in-dash screen via an H.264 video stream, according to Volvo. Apple's long-standing "AirPlay mirroring" feature -- which allows users to mirror the display of a compatible Mac or iOS device to an Apple TV --?works the same way, encoding display output in H.264 and transmitting it over a standard TCP network connection.
CarPlay goes further, Volvo said, by providing a means to return input from the vehicle's touchscreen to the user's iPhone. Such a facility for monitoring and transmitting control events is already built in to AirPlay, allowing users to control media playback through their AirPlay-enabled speakers or Apple TV.
Though AirPlay is a wireless standard and CarPlay requires an iPhone tethered via a special Lightning cable, there are indications that Apple intends for future revisions to function wirelessly. Volvo initially said that Wi-Fi support is "coming in the near future" before removing that statement from press materials, perhaps a sign that CarPlay over Wi-Fi is simply not yet ready for a public debut.
The most overt indication that CarPlay springs from the AirPlay family tree, however, came from Mercedes-Benz. Touting CarPlay's ease-of-use during a press event in advance of this week's Geneva Auto Show, one executive from the German marque called out the streaming standard by name.
"If you know Apple's AirPlay, you know what I'm talking about," he told the assembled crowd.