Don't Buy That UHD TV: It May Go Obsolete Faster Than You Think
Yesterday Tech Radar reported that Panasonic's AX800 UHD TV won't play Netflix 4K, and never will. No technical explanation as to why, but since Netflix is the first major broadcaster using HEVC, it's a big deal. I wouldn't want my year-end bonus based on sales of that particular model.
I don't know exactly why the AX800 won't play Netflix 4K, but I want to discuss a few trends and ways to future-proof your UHD purchase.
First, like H.264, HEVC has multiple profiles. The Main profile is an 8-bit profile, while Main 10 is a 10-bit profile. Most producers are using the Main 10 profile because it produces better quality, and obviously that's a trend that will continue. Video encoded using the Main 10 profile won't play on decoders that only support Main profile decode.
That's not the case with the AX800, which is powered by ViXS Systems 6403 System-on-Chip, which does support the Main 10 profile. But, it's possible than some older UHD sets are powered by chips that don't. Since most TV vendors don't list the HEVC profiles supported by their sets (Panasonic just says HEVC for the AX800), it's really hard do know. If you see a heavily discounted older model, be concerned.
How can consumers protect themselves? Confirm Main 10 support by identifying the chip used in the system; or buy a set without an HEVC decoder; or buy a set with HDMI 2.0, which is fast enough to carry a 4K 60 signal (older versions can't). This way, if your HEVC decoder is obsolete, you can use a set-top box to decode the signal and send it to the set.
Will TV vendors specify which version of HDMI they support? Panasonic doesn't say HDMI 2.0, but it does say "4K 60," which should amount to the same thing.
Color Space Issues Coming
Main 10 support is the first major issue, but if you wait 18 to 24 months to buy a UHD set, there's another issue coming: the shift from 8-bit to 10-bit displays.
Images from Sakurambo and GrandDrake as found in an article from HD Guru
ITU-R Recommendation BT.2020, more commonly called Rec. 2020, is the color space standard for UHD TV (10-bit is required) and Rec. 709 is the spec for HDTV (8-bit is OK). The first generation of UHD sets use 8-bit Rec. 709 displays because Rec. 2020 parts weren’t available. As the figure above shows, Rec. 2020 addresses a greater range of color space, which means less banding and a higher quality color display.
This thread in the AVS forum describes the problem. The bottom line is this chilling quote from HDTVChallenged:
I'm pretty sure that if you buy *any* "4K" set today, you can probably count on it being "obsolete" in one way or the other if/when the dust settles on "4K/UHD" and programming becomes more available. Been there, done it ... ain't gonna do the bleedin' this time.
Hollywood wants to transition to Rec. 2020 displays as soon as possible for the additional colors, and are encoding with the Main 10 Profile. While virtually all existing UHD sets currently use Rec. 709 displays, the changeover to Rec. 2020 will happen sooner or later. Consumers should avoid buying a set with a Rec. 709 display unless they get a great price.
Anyone buying a UHD set today should do their due diligence on the Main vs. Main 10 issue, and also the Netflix issue. I personally wouldn't buy a set I didn't see playing "House of Cards" in 4K in the store. Down the road, be aware of the shift from Rec. 709 to Rec. 2020. And don't buy a set without HDMI 2.0.
Set-top boxes take a backseat, notes the Council for Research Excellence. Also, children have a big influence on what technology enters the home.
Which codec delivers better image quality? Which is more compatible? And what about Daala, the spoiler codec currently being developed from scratch?
Thinking about running a 4K? While early adopters with fat wallets are buying UHD televisions, most people should wait for more content and lower prices.
Unless the industry decides on greater UHD improvements and educates buyers, UHD TV will be reduced to a resolution number.
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