High dynamic range (HDR) televisions are now in their second year, and most 2016 higher-end displays and supporting 4K Ultra HD source devices are equipped with at least one of the latest HDR-metadata-supporting HDMI 2.0a connectors
Meanwhile, 4K content mastered with HDR metadata is ramping up through streaming services and Ultra HD Blu-ray discs. So now, we are often asked, is it the right time buy a 4K Ultra HDTV or 4K player?
The simple answer is: probably. Most of the pieces are now in place to enjoy the benefits of 4K Ultra HD delivering, via inclusion of HDR and a wider color gamut, pictures that are clearly better than the best Full HD 1080p displays present.
The caveat is that work is always proceeding on next-generation standards which typically require new digital input interfaces (connectors), so don’t expect anything you buy today (or ever, really) to remain compatible with the next new advancement for long.
Read more on what to expect from the next digital interface connector after the jump:
Just remember, you’ll be able to enjoy on many products you buy today the stunning benefits of 4K Ultra HD with HDR for years to come. The question is just which form of HDR will you be watching – HDR-10, Dolby Vision, both, or something else?
The open HDR-10 format has been established through the Blu-ray Disc Association (BDA) as the mandatory HDR format all players are to support. It requires the HDMI 2.0a digital interface connector with HDCP 2.2 copy protection to deliver the necessary metadata (instructions to the TV for displaying HDR) from the player to the display.
The Dolby Vision format, which is also gaining momentum as an alternative – and some say superior – HDR format is deemed “optional.” It will work with even older HDMI interface standards than HDMI 2.0a and offers “dynamic HDR” that allows grading deeper colors in HDR at various levels on a scene-by-scene basis when mastering content.
Roland Vlaicu, Dolby Laboratories consumer imaging VP, told us: “We embed the Dolby Vision metadata into the video signal. Knowing that previous versions of HDMI would not pass the Dolby Vision dynamic metadata, we developed a way to carry this dynamic metadata across HDMI interfaces as far back as v1.4b. The HDMI specification is now catching up with v2.0a supporting static metadata and future versions expected to support dynamic metadata as well. Dolby is also directly involved in supporting current and future versions of HDMI standardization.”
The HDR-10 format, on the other hand, is based on “static” metadata that uses consistent (static) grading throughout an entire movie or program in the mastering process.
Dynamic HDR metadata would presumably give filmmakers greater artistic flexibility in using a wider contrast range. But how discernible that difference is from static HDR is a matter of debate.
According to Dolby’s Vlaicu, the benefit of dynamic HDR “is the ability to preserve artistic intent. Scene-by-scene optimization allows the picture for each scene to retain detail, and achieve natural contrast and vivid color using dynamic metadata. The Dolby Vision grading process uses a high dynamic range and wide color gamut display allowing creative professionals to establish their artistic intent through the use of a large palette. Dolby Vision enabled Color Grading systems provide new features to analyze the artistic intent by creating metadata. This metadata is then preserved throughout the Dolby Vision encoding system, and finally decoded in the Dolby Vision enabled device to maintain artistic intent from the creative process to the consumer.”
In 2016 certain LG and Vizio 4K Ultra HDTVs will support both Dolby Vision and HDR-10 HDR. Philips (made by the Funai company from Japan) and TCL have also pledged support for both formats in select 4K Ultra HDTV models.
According to Dolby, anyone looking for an HDR-supporting 4K Ultra HD TV today, should consider one that supports both Dolby Vision and HDR-10.
“A TV that includes the Dolby Vision VS10 playback solution offers both Dolby Vision and HDR-10 support. This maximizes the value for consumers as only TVs with Dolby Vision offer the best HDR quality along with maximum content choice,” Vlaicu said.
Meanwhile, Philips (from the Netherlands) last August posted a whitepaper with a proposed third HDR solution that also calls for dynamic HDR. Unlike Dolby Vision, that format will require a new digital connector interface.
According to Philips, the Society of Motion Pictures & Television Engineers (SMPTE) is standardizing the Philips dynamic metadata set in ST 2094-20, and “the characteristics of the display used for grading or monitoring, such as peak luminance and black level, are added as SMPTE ST 2086 metadata to the video stream.”
Dolby said that Dolby Vision dynamic metadata also is being standardized in SMPTE 2094-10.
“This is not a requirement for Dolby Vision as it is deployed in the market today but is generally desirable from a long-term perspective and particularly important to those content owners who archive their high-value content using the Dolby Vision mastering workflow,” Vlaicu told HD Guru.
According to the Philips HDR whitepaper, the current HDMI 2.0a connector standard is not sufficient for its HDR proposal, and work is proceeding to develop a new HDMI connector that could accommodate it and other things.
Next HDMI Standard
Back in January at CES 2016, the HDMI Forum tipped its hand to the on-going development of the next HDMI standard (HDMI 2.1?) when Robert Blanchard, Forum president said: “The next version of the HDMI specification targets 8K resolution, enhanced High Dynamic Range and other important features such as delivering power over the interface to products such as streaming media sticks.”
Because the HDMI Forum continues to work on the next HDMI version, it still isn’t saying exactly what the new specifications are likely to bring, when it will arrive and whether or not is will be deliverable by a firmware update or require new hardware.
Because 8K support was mentioned as one of the new target benefits, it will likely require a new physical connector with additional pins to supply the necessary bandwidth to support the greater resolution demands as well as faster frame rates (possibly up to 120 Hz has been suggested) to support high motion sequences in 4K and 8K.
Dynamic HDR For SDR TVs
Meanwhile, using dynamic metadata would also offer an accurate means of down-converting HDR for use on standard dynamic range (SDR) TVs, presumably with some picture enhancement.
Interestingly, Samsung, which is a firm and exclusive supporter of the HDR-10 format in 4K Ultra HDTVs, has demonstrated its technology for HDR with “dynamic tone mapping,” which is an open candidate for SMPTE HDR standards.
Tone mapping is a technique used in image processing to map one set of colors to another to approximate the appearance of HDR images on displays with more limited dynamic range capabilities.
Alternative Next Generation Interfaces
In addition to developing a new version of HDMI a couple of alternative digital connector interfaces are already available today.
The Video Electronics Standards Association (VESA) announced in March a new DisplayPort 1.4 interface, which followed the announcement of a superMHL digital interface in January 2015. Both offer greater bandwidth and speed than HDMI 2.0a and will support dynamic HDR metadata.
Before we go further, it should be pointed out that HDMI has a huge installed base of devices all over the world, and most versions of the spec have supported backward compatibility with prior versions. It is going to take nothing short of a political sea change to get the consumer electronics industry to move to an entirely new digital interface standard.
DisplayPort has been used as a connector standard primarily for computer/IP devices, but its blazing speed, and wide bandwidth makes it a tempting alternative for next-generation audio/video entertainment purposes.
The DisplayPort 1.4 interface was announced by VESA in early March, and will support up to 60Hz 8K displays with HDR color modes at 5K and 8K. It continues to have the DisplayPort 1.3 High Bit Rate 3 capability, which provides up to 8.1Gbps of bandwidth per lane and will support Display Stream compression (DSC), which VESA calls a “visually lossless” form of compression that enables up to a 3:1 compression ratio. The DSC contributes to DisplayPort 1.4’s ability to drive 60Hz 8K displays and 120Hz 4K displays with HDR “deep color” over both DisplayPort and USB Type-C cables. DisplayPort has been compatible with USB Type-C connectors via the USB Alternate Mode spec.
Meanwhile, superMHL adds a huge boost in speed and capability to the MHL connector standard that has enabled sharing video and data signals between mobile devices and HDMI-enabled HDTVs using a special adapter cable. The new superMHL version offers a 32-pin, symmetrical full-size connector. It supports Display Stream Compression, is compatible with the new USB Type-C connector interface, and has a maximum data rate of 36 Gbps of data, which the MHL Consortium said is fast enough to handle up to 8K (7680×4320) video with up to a 120 Hz refresh/frame rate and 4:2:0 chroma subsampling.
When we can expect to see one or all of these new connectors to start appearing on consumer television sets and source devices is anybody’s guess. Past practices would suggest about one to two years, but whether or not you are really going to need any of the feature enhancements they will carry will depend on your need to be on the cutting edge.
Bottom line: any higher-end 2016 4K Ultra HDTV with HDR support that you buy today should continue to deliver the quality and value you expect for at least the next seven years. Enjoy!
By Greg Tarr
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