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Displayport V1.2 To Take Giant Leap Over HDMI
An anonymous reader writes "With HDMI becoming increasingly common, Displayport has been slow to emerge as a widely used connection interface, but a plethora of new features in the new v1.2 standard could see that change. As well as doubling the data rate of the existing v1.1a standard to 21.6 Gbps, the update allows for multiple monitors to be connected to a single Displayport connector and adds support for transporting USB data at up to 720Mbps, enabling embedded webcams, speakers and USB hubs over a single cable. Ethernet data is also supported. The improved data rate will allow for richer, larger and higher resolution displays, and the new version is also backward compatible with the current display technology, so all the ports, cables and devices will be interchangeable, although they will revert to the lowest common denominator."
I hate Apple as much as the next guy, but not mentioning them at all in the summary is a bit... crude. Also, here's a list of all the new stuff (taken from http://www.hardmac.com/news/2010/01/11/displayport-1-2-validated).
* Doubling bandwidth mostly to support 3D: 21.6 Gbits/s.
* Connect even more monitors from a single DisplayPort. Dedicated hubs should soon be available.
* As for the HDMI, transport USB data between a computer and a display, supporting Display USB functions such as a webcam and USB hub.
* Connect to display with 3840 x 2400 resolution at 60Hz, or a 3D display (120Hz) at 2560 x 1600.
* Audio Copy Protection and category codes
* High definition audio formats (such as Dolby MAT, DTS HD, all BD formats,etc.)
* Synchronization assist between audio and video, multiple audio channels, and multiple audio sink devices using Global Time Code (GTC)
This problem was solved a few years ago. Look up ClearCurve. They clad the fibre in tiny reflectors that recover the stray signal.
The new Thinkpads that my office has been getting has Displayport on the back of the laptops, and docking stations. Of course, Lenovo doesn't make a monitor with displayport under something like 24".
What are we going to do tonight Brain?
HDMI needs additional chips/control circuits on the transmitting and receiving end to deal with encoding and decoding. Display Port is directly compatible with the display panels themselves and as such
...can't display motion pictures published by six American companies. Home users who expect to watch high-definition feature films will choose an interconnect that does "encoding and decoding" because the publishers of feature films on high-definition home video demand "encoding and decoding" for digital restrictions management. Sure, DisplayPort 1.1 and later allow for DPCP, but then you lose the advantage of no "encoding and decoding".
Multiple display support, for one. You can use DisplayPort to daisy chain multiple screens. While there is a dual-link spec for HDMI, it only supports 2 display devices and isn't supported by anyone.
Also, DisplayPort was designed from the ground up for bidirectional communication (ie- touch input, camera, mic input, etc). These features have only recently been shoehorned into the HDMI 1.4 spec, and may be some time before one can actually use it.
Sigs are for losers
Try this: http://techresearch.intel.com/articles/None/1813.htm
Expenses. The Sony/Philips optical is about the only consumer optical in common use, but that's over plastic, driven by LEDs. Pretty cheap. For optical at these rates, you'd need real lasers (LEDs peak around 500Mb/s) something like 10GBASE-R or 10GBASE-SR cable (LOMMF/OM3). None of that's crazy expensive... unless you compare it to electrical. And in particular, the electrical that the equipment makers are actually paying for.
Keep in mind, these are the industry guys who got together to create DisplayPort, at least in part because they got bent out of shape having to pay US$0.04 per device to use HDMI. They're not likely to replace a $0.50 electrical connector with a $2.00 optical connector and $5.00+ laser. And of course, lasers go one way... you actually need a laser at each end, if you want 2-way traffic. Or a custom cable, with electrical backchannel.
Well, why not.. I have some video cables around here with integrated optical audio channel.
So this is the next one up, after DisplayPort, but designed as a general purpose standard: Light Peak. I think this started out as an optical answer to Firewire at Apple, but rather than do it themselves, change too much for the spec, and have Intel (and the rest of the PC industry) go and create an alternative, this time Apple brought it to Intel. Maybe.. at least that's one story.
Anyway, read more here: http://en.wikipedia.org/wiki/Light_Peak
The nice thing about Light Peak... it's fast enough to do the HDMI/DisplayPort thing. And replace SATA, USB, Firewire, anything else you want. Of course, like all optical interconnects, the connectors are an issue (dirt kills), and unless they go to some kind of FDM, they'll need one cable in each direction, just like 10Ge uses in its various optical forms. Then there's the issue of power... we're kind of used to USB and Firewire cables providing power for small devices. But it's still a work in progress, 10Gb/s on launch, up to 100Gb/s on the roadmap.
-Dave Haynie