Tuesday, 3 February 2009
The battle of the video sockets!
One of the annoying things when a consumer tries to connect different bits of kit around the home together is that the video in and out connectors vary so much across devices. High end TVs now typically carry an array of SCART, HDMI, Component, Composite, and VGA connectors amongst others. PCs may have VGA, DVI or the newer DisplayPort standard connectors. In this post I am going to compare the latest and greatest from each of these device types as we look to the future, HDMI and DisplayPort.
VESA (Video Electronics Standards Association) actually introduced DisplayPort in 2006, ratifying v1.1a of the standard a year later. Silicon support for it in graphics cards and north bridge processor chipsets is growing and device manufacturers will start to exploit this in the coming year(s) with products which use it. Unlike HDMI (High Definition Multimedia Interface) which is charged at $5-10K p.a. and a levy of around 4 cents per device, DisplayPort is royalty-free and so attractive to product manufacturers. Whereas HDMI is only used externally to connect different devices together, DisplayPort is also targeted at internal use between board and display inside devices. Hence it also replaces the need for LVDS (Low Voltage Differential Signalling) circuitry which is currently used inside both PCs and CE (Consumer Electronics) products for this internal video connection.
From a technical perspective, DisplayPort is lower power and requires fewer, thinner wires in the cabling, which will be important in the race to produce even slimmer displays. The low power advantage will also be important to silicon vendors as process geometry goes below 45nm. DisplayPort uses a packet based architecture, allowing audio, video and control signals to be handled in a consistent single packet stream. HDMI uses separate streams (or channels) for each of audio, video and control.
HDMI's current advantage is that there are millions of CE products already out in the marketplace with HDMI sockets on them, especially HD TVs. I believe that over time, this advantage will be eroded. DisplayPort will first make its mark internally in PCs and then externally on laptops and other PCs and related products. Apple has already reduced the footprint of its video out sockets on its latest notebook computers by designing and freely licensing a 'mini-displayport' connector, which conforms to the VESA DisplayPort standard. In the future, probably beyond 5 years, will we see DisplayPort begin to make a significant presence in CE products including televisions. Hopefully future attempts to cable video between CE products in the home will be simpler!