Automobile buyers today rank infotainment as key differentiating criteria. Their shopping list includes better sound and picture quality for those long and short trips. Some even desire to extend their home theater into their ride. However, getting the high-definition content into the car has its challenges.
For example, how does a passenger simultaneously get Blu-ray quality video on front-passenger and rear-seat LCDs (liquid crystal displays)? The buyer wants it as quick and easy as inserting the high-def disc and hitting play, but first there are automotive design problems to solve.
One of the new engineering challenges for delivering high-definition multimedia data streams in the automotive environment is content protection. Not only must the architects and designers conquer video data throughput, routing to multiple displays, and address reliability requirements, they also must protect the content against unauthorized use.
The major content producers such as The Walt Disney Co., Warner Bros., and Sony Pictures Entertainment want their customers to enjoy high-quality films in the vehicle, but they also want to protect their content. Physical media (Blu-ray disc) encryption protection is the same for the home system and the vehicle. But protecting the raw video transfer from the Blu-ray player to the displays is the infotainment system designer’s challenge.
In the home entertainment system, HDMI (high-definition multimedia interface) cables provide HDCP (high-bandwidth digital content protection), which relies on authentication and encryption specified by Digital Content Protection (DCP) LLC (see www.digital-cp.com for details). However, HDMI is not practical in a car because of the bulky and expensive cable assemblies.
Infotainment architects require a flexible, highly reliable, and inexpensive cable assembly solution. The ideal solution carries the digital video and control signals over a single twisted-pair cable using an approved HDCP-protected interface protocol. National Semiconductor’s FPD-Link III chipset designed specifically for infotainment applications is an ideal fit.
There are three components to the content protection chain. They are the media, the source, and the sink. In the automotive application, the head unit source converts the media content to RGB video, and then it sends that video to the displays for viewing. This transfer link requires the HDCP provided by FPD-Link III.
All infotainment equipment manufacturers choosing to implement HDCP need a license from DCP. As license agreement adopters, they agree to secure the highly confidential information such as keys. They typically do this by buying HDCP-protected interface chips such as FPD-Link III with the keys already burned in during the chip manufacturing process. This way the responsibility for securing keys on a manufacturing floor is National Semiconductor’s responsibility.
The FPD-Link III chips come with the device private keys and the key selection vector already inserted. National Semiconductor buys the keys and vector from the DCP and ensures the confidential information’s security through the manufacturing process. Then fellow adopters buy these chips to build their licensed HDCP products. This process protects the confidential information, which in turn protects the content for the content producers, and ultimately allows end consumers to enjoy their auto-mobile home theater.
Stephen Kempainen of National Semiconductor wrote this article for Automotive Engineering.