4K UHD TVs were all dressed up at CES 2014 with no content to show. The good news for the 2014 holiday season is the industry has converged on one set of standards for display, interfacing, and encoding, so consumers should not be left marooned in an instant replay of the 3DTV hype-crash cycle. It may be a bit longer before everyone can see 4K, but there has been significant progress.
First, what is 4K UHD? The Consumer Electronics Association did a fantastic job of rodeo-roping, heading off a potential stampede of competing ultra-high-definition television standards that would have messed up the entire supply chain. To qualify for 4K UHD branding, a display must be at least 3840 x 2160 pixels. Much of the literature describes 2160p, the logical successor to 1080p, essentially quadrupling the number of pixels in play.
“Hey, my Blu-Ray player already plays 4K!” Not exactly. Today, either the Blu-Ray player or the 4K UHD TV is upconverting 1080p to 4K UHD format. Official 4K Blu-Ray support is coming for the 2015 holiday season. One of the key developments in the newest standard is a move from H.264 (Advanced Video Coding or AVC) to the newer H.265, commonly known as High Efficiency Video Encoding (HEVC).
“Dude, my DIRECTV is 4K!” Read the fine print before getting too excited. True, DIRECTV has just launched 19 movies in 4K UHD format. However, the service only works on a late model Samsung 4K UHD TV that supports DIRECTV RVU. The Genie HD34 or later model DVR is simply passing through 4K UHD content for the Samsung TV to do the heavy lifting of decoding HEVC.
“Oh yeah, Netflix is 4K!” Yep, if you have a need for “House of Cards”, “Breaking Bad”, “The Blacklist”, or a few other shows, Netflix has 4K UHD – for a price. Here is where the real fun starts. Netflix has a certification process; not every 4K UHD TV with an HEVC decoder is currently Netflix-certifed. Maybe more importantly, Netflix recommends a 25Mbps Internet download connection speed for 4K UHD content. (Cox has apparently been hard at work here in suburban Phoenix; I just measured 31.92Mbps.)
Why isn’t every chipset certified? Some of the early HEVC movers didn’t have complete standards support. Besides moving four times the number of pixels, 4K UHD has a new color gamut – ITU-R Recommendation BT.2020, aka Rec. 2020. Color is a very complicated conversation, but a metric helps: Rec. 2020 with its 10-bit color representation covers 75.8% of the standard color space, while Rec. 709 in 8-bit for existing HDTV only covers 35.9%.
via Wikimedia Commons, user “GrandDrake”
Most of the non-compliant chipsets support only 8-bit color, or can’t decode enough frames to keep up with streaming. HEVC deploys a new set of algorithms to achieve higher bit rate encoding – meaning more compression to help offset the greater resolution in 4K UHD. This calls for increased processing using both CPU and GPU cores in order to stream 4K UHD content. Most solutions are taking a software approach, such as Ittiam, to decode streams using the appropriate resources.
How much horsepower does HEVC take? One SoC targeting next-gen STBs with 4K UHD capability is the STMicro STiH418. This device packs four ARM Cortex-A9 cores with a quad-core ARM Mali GPU (likely in the Mali-T600 family, exact version undisclosed as of yet) along with ST’s Faroudja video transcode subsystem. It also supports HDMI 2.0, USB 3.0, eSATA, PCIe, and Gigabit Ethernet interfaces, along with the ability to add front-end chips supporting DOCSIS 3.0, MoCA 2.0, and 802.11ac Wi-Fi interfaces. The STiH418 is among the first chips to provide complete support for 4K UHD streaming up to 60 fps, HEVC level 5.1.
HEVC is for more than TVs and set-top boxes. Apple is making use of H.265 in FaceTime on the iPhone 6, presumably with the help of the Imagination Series 6XT 4 core GX6450 GPU inside the Apple A8 SoC. Microsoft has leaked that it is supporting HEVC in Windows 10. The much-awaited Android 5.0 “Lollipop” release also supports HEVC, which may provide to be a key driver in set-top boxes running Android TV.
All the signs – mobile, set-top box, TV, disc player, and streaming content – are pointing toward 4K UHD with HEVC as the winner. It may take another year or two for enough content to materialize, and in some locales streaming bandwidth may be an issue, but the standards are aligned and mainstream devices with 2H2014 SoCs and beyond should be ready for the shift.