You might be hearing about a new technology called MirrorLink that mimics your smartphone’s screen on the larger nav screen in your “connected car”. Or, you might be following the news on Miracast, a more open standard now baked into Android that offers Apple AirPlay-like features to stream smartphone content to devices like connected TVs.
You’d be forgiven if you think the two similarly-named standards are trying to accomplish the same thing. I didn’t understand it either, so I did some digging. Here’s what I found out.
The Smart, Connected Car
When I attended the Paris Auto Show last Fall specifically to investigate in-vehicle infotainment (IVI) trends for the Barr Group under contract to Intel, I got spun up “right quick” on all manner of IVI. From BMW’s iDrive to Chevrolet’s MyLink, the connected car is here. In fact, it’s one of the biggest trends spotted at last week’s 2013 CES in Las Vegas. MirrorLink is being designed into lots of new cars.
The biggest question faced by every auto manufacturer is this: in-car native system, or rely on the apps in one’s smartphone? Ford’s industry breakthrough MyFord Touch with SYNC by Microsoft is native and based upon Microsoft Auto Platform (now called Windows Embedded Automotive 7). Elsewhere, premium brands like BMW, Lexus and Cadillac have designed self-contained systems from the ground up. Some, like BMW, include in-car cellular modems. Others rely on the smartphone only for music and Internet access, but that’s it.
Still others, like Toyota and Chevrolet use a technology called MirrorLink to “mirror” the smartphone’s screen onto the car’s larger IVI. For all apps that make sense to be viewed on the IVI, the system will display them — usually identically to what the user sees on the smartphone (subject to safety and distraction caveats).
MirrorLink is now a trademarked standard owned by the Car Connectivity Consortium that’s designed specifically for cars and smartphones. That means the standard worries about driver distractions, apps that make sense for drivers (such as Google Maps) and those that don’t (such as a panoramic camera stitching application). Apps have to be qualified for use with MirrorLink.
As well, MirrorLink replaces the phone’s touch I/O with in-car I/O such as steering wheel controls, console joysticks, or the IVI head unit’s touchscreen or bezel buttons. Equally as important, audio input from microphones is routed from the car to the phone, while output uses the car’s speakers. The car’s antennae for radio and GPS will be given preference over the phone’s, improving the signal reception. The protocols between smartphone and car also take input from the vehicle’s CANbus, including speed. This means that you can check your email when parked, but not while driving. A great resource for how it works and what the future holds is here.
MirrorLink started as a Nokia idea that was intended for smartphone-to-car connectivity. Now at version 1.1, it’s a client-server architecture where the IVI head unit is the USB host. It uses industry-standard protocols such as Internet Protocol (IP), USB, Wi-Fi, Bluetooth (BT HFP for telephony, BT A2DP for media), RTP, and UPnP. Recent additions use The Trusted Computing Group concepts of device attestation protocols with SKSD/PKSD keys via authentication. The actual screen sharing uses the VNC protocol.
What MirrorLink doesn’t yet support is video streaming, since drivers watching video is a no-no is cars (tell that to the Japanese who I’ve seen with TVs mounted in their cars!).
Android and Miracast
Miracast, on the other hand, is all about streaming. It’s a Wi-Fi Alliance spec recently demoed at CES 2013 that’s designed to stream video and photos from smartphones, tablets, and future embedded devices. Like Apple’s AirPlay, it moves stuff from a small screen onto a big TV screen. It’s based upon Wi-Fi’s not-new-but-rarely-used Wi-Fi Direct standard (WiDi 3.5) that avoids routers to establish peer-to-peer connectivity.
Miracast supports 1080p HD video, 5.1 surround, and CPUs from nVidia, TI, Qualcomm, Marvell and others have announced plans to support it. Built into the spec is the ability to stream DRM and HDCP protected content using already established HDMI and DisplayPort style copy protection schemes. I guess they figure if you’ve got the rights to play it on your phone, might as well play it on your TV too.
Last Fall, Google updated Android Jelly Bean to 4.2 and included Miracast as part of the update, and I’m thrilled that my Nexus 7 tablet can now, in theory, stream content to my Samsung Smart TV. As Android proliferates throughout the embedded market, I can envision commercial applications where a user might do more than stream a video to another embedded device. Sharing the entire smartphone’s screen can be useful for PowerPoint presentations or demoing just about any Android app in existence. If it’s on the phone’s screen, it can get mirrored via Wi-Fi to another screen.
Will MirrorLink and Miracast Converge?
I doubt the two standards will merge. MirrorLink is exclusively aimed at IVI systems in cars, and the closely curated standard is intended to vet applications to assure safe operation in a vehicle. Miracast is similar in that it mirrors a smartphone’s screen, but there are no limitations on moving between screens, so Miracast is clearly the superset standard to a broader market.
Ironically, as the Car Connectivity Consortium looks to release MirrorLink Version 2.0, they’re examining Miracast as a way to provide an “alternative video link” for streaming H.264 1080p@30 FPS into the car cabin.
Why? For passenger entertainment. Think about minivans (shudder) and Suburbans loaded with kids.