VESA updates DisplayPort Dual-Mode, pushes 4K UHD over HDMI

By on February 1, 2013, 4:30 PM

Industry standards body VESA has officially updated its DisplayPort Dual-Mode 1.1 standard to provide better performance, higher resolutions and increased interoperability when hooking up to HDMI and DVI ports through a cable or adapter. Under Dual-Mode, a DisplayPort can output an additional HDMI/DVI-compatible signal alongside its expected DisplayPort link. This allows for connectivity to HDMI and DVI-equipped devices without the need for cables or converters equipped with active electronics.

Current DisplayPort Dual-Mode converters/adapters suffer from a limited output of 1080p @ 60Hz with 24-bit color. VESA's update includes support for just about anything HDMI 1.4 can handle -- deep-color, 3D 1080p @ 60Hz and 4K UHD (2160p) @ 30Hz -- but all through a single cable. These improvements are achieved by nearly doubling the TMDS (Transitional-Minimized Differential Signal) rate from 165MHz to 300MHz.

It's worth noting the current DisplayPort standard (pdf) itself has no trouble delivering 4K UHD signals @ 60Hz and 24-bit color.

DisplayPort adapters and cables which meet the new specifications will be referred to as "Type 2". Previous-generation devices, cables and adapters will be henceforce labeled as "Type 1". Type 2 (300MHz) adapters will be compatible with existing 165MHz Type 1 source devices, but the performance of such adapters are downgraded to 165MHz for compatibility. However, in some cases, a software update may allow existing Type 1 devices to take full advantage of Type 2 features and performance.

The updated standard comes at an auspicious time when ultra high-def displays are are clearly on the way. If CES is any indication (and it likely is), 4K UHD and even 8K UHD televisions and displays are imminent. Japan's government seems to agree with that assessment.




User Comments: 10

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VitalyT VitalyT said:

HDMI, Display Port, DVI, VGA, Thunderbolt, USB, Composite Video

Anybody wants another type of video connector?

Darth Shiv Darth Shiv said:

VGA shouldn't really be used anymore for new PCs at least. Composite is a waste of time now too. USB never really been a serious player. Display Port... adoption for home users is poor except on Mac? I do wonder though... DisplayPort should have lower input lag than HDMI I would have thought. Thunderbolt hasn't taken off yet. Still to see if it does.

captaincranky captaincranky, TechSpot Addict, said:

....[ ].....Composite is a waste of time now too....[ ]...
For computer use, probably. However, HDMI interface has a quirk that won't allow you to set aspect ratio going from a player of some type to a TV. So, I use it once in a blue moon.

...[ ].....Display Port... adoption for home users is poor except on Mac? I do wonder though... DisplayPort should have lower input lag than HDMI I would have thought.
No, monitor manufacturers are using the display port interface to get around the licensing fee for HDMI connection. I have a 24" HP ZR24W that doesn't have HDMI, only display port.

Ostensibly, Display port and HDMI should have the same video characteristics, sans the sound. Since specs are changing all the time, I'm not willing to stake my bad reputation on the veracity of that though.

dividebyzero dividebyzero, trainee n00b, said:

HDMI, Display Port, DVI, VGA, Thunderbolt, USB, Composite Video

Anybody wants another type of video connector?

Analog VGA and Component (or YPbPr, which is what I believe you meant), and DVI don't have the bandwidth for a 4K display- and even if they did, a lack of standardized signal quality guidelines and HDCP makes them a non-starter going forward as far as industry vendors are concerned.

That pretty much leaves DisplayPort, HDMI and Thunderbolt the only real options, with the latter having a decided advantage if high bandwidth become the prime mover- and with 22.2 multichannel audio already mandated for the 4K spec, 60Hz refresh rate being more a starting point ( since 100Hz and 120Hz refresh panels are already being publicized), and provision for 30-bit colour you could see how the specification might need to take into account some serious bandwidth in future.

VitalyT VitalyT said:

30-bit color? Surely you meant 10-bit color? At least that's what it is called in the industry, 10-bit per channel, where a channel is one of the RGB-s And those TV-s have been out there for years now, not much of a provision

By the way, the latest USB3 video links support up to 2560x1600, which is the maximum resolution on a today's 30" monitor So, they are still in the game, just few people use them.

2 people like this | dividebyzero dividebyzero, trainee n00b, said:

30-bit color? Surely you meant 10-bit color?

Call it whatever you like, the fact remains that the bandwidth needs to be accounted for either by raising the bandwidth throughput, or lowering refresh rate, if you aren't sacrificing colour depth. I'm not convinced that nitpicking a naming convention makes for a valid strategy in defending your argument tbh.

And those TV-s have been out there for years now, not much of a provision

Those panels generally tend towards a trade-off between colour depth against refresh rate. I think you'll also find that Deep Colour TV relies upon HDMI 1.3/1.4 input in almost every case, so that kind of blows your argument for the inclusion of VGA, Component, and USB....assuming the bandwidth limitation, lack of signalling standards, and lack of HDCP support haven't already done so to your satisfaction.

By the way, the latest USB3 video links support up to 2560x1600, which is the maximum resolution on a today's 30" monitor So, they are still in the game, just few people use them.

The reason "few people" use USB as a display interface is more a product of latency issues and a lack of actual bandwidth. USB 3.0 is supposed to reach 5000Mbps (625MB/sec). After you deduct 8B/10B encoding and protocol overheads, packet framing, and flow control, you're left with around 3200Mbps (400MB/sec) - and that is being generous.

VitalyT VitalyT said:

Yeah, and it was deep and I'm not up for a war today, especially after the first post being there just for irony anyway

Hatchet buried

Darth Shiv Darth Shiv said:

Yeah man no worries... just hoping some of them aren't taken seriously!

Guest said:

I am thrilled about this news.

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