The mobile industry originally assumed small displays would be mostly used “for simple user interfaces, webs and games,” said Tom McMahon, video expert and founder of The Del Rey Consultancy. But that’s no longer true. Devices are coming out with higher resolution displays, and consumers are watching more video on tablets than anyone in the mobile industry originally expected.
Coupling this industry-wide trend [for higher-resolution mobile displays] with consumers’ craving UHDTV, the mobile industry “needs to figure out a way to do display processing, or signal processing, either in a box [tablet] or in a head-end from which video is being distributed, McMahon noted.
DisplaySearch’s Shim acknowledged that display processing is one solution that could improve the video playback experience. “The challenge is that as far as I know there aren’t any display processors available in volume specifically for tablets,” he said. “Another challenge would be cost. As tablet average selling prices continue to fall, adding new components will be difficult.”
McMahon agreed. “There is cost for power, and the cost for silicon. Something’s got to give. You need to pay for it.”
Bruce Walicek, president and CEO at Pixelworks, is one executive willing to discuss how display processing technology is becoming even more important on mobile devices.
In the company’s earning call earlier this year, Walicek noted a “gigantic tsunami of pixels that are headed for the entire ecosystem” and talked of Pixelworks’ display processing technology, now powering many of the tier-one TV manufacturers’ Ultra High Definition TVs. During the call, he said, “Higher resolution of course means more noticeable video quality problems, and video quality problems associated with higher-resolution larger screens are now migrating to small ones.” Although he stopped short of disclosing his company’s product plan, Pixelworks appears focused on developing a display processor specifically designed for mobile screens.
Of course, “there are a billion different ways to up convert video,” said McMahon. McMahon, who used to work for Microsoft and Broadcom, explained, “Whether it is a motion estimation, motion vector or motion protection, there are different ways to estimate--or guessing--where the pixel goes next. It’s an interpolation over time.” A company like Farudja Labs, later acquired by ST Microelectronics, worked for years on the development of video processing algorithms and products that powered large-screen TVs, he added.
Bringing the level of sophisticated display processing currently used in a large-screen UHDTV to mobile devices is a stretch. The issue of cost is compounded by the impact on battery life. Beyond an external display processor chip, this could require a much more holistic system-level approach.
Noting that today’s tablets consist of “pretty much one big system-on-chip and battery,” McMahon speculated that vendors such as Qualcomm and Broadcom are likely working to integrate some level of display processing.
Just to be clear, if you are streaming videos onto your tablet from Netflix, for example, you need a good connection on WiFi or 4G LTE. But you'll be streaming 1080p at best--which even then is a slightly lower resolution than the iPad Retina screen. Obviously, with a less-than-optimal connection, video quality continues to decline. But what happens in video streaming or even in video chat is that the frame rate is often reduced, which results in judder. If a new mobile display processor is capable of frame-rate conversion, it can, in theory, recover the original frame rate, making it smooth again.