News Detail
News Archive >> What's the difference between HD....................
Details
For more frequently asked questions, please visit HDMI Australia
Q1. What's the difference between "HD" and "Full HD"?
A1. The term "High Definition" (HD) is used to describe the reproduction of video and/or film in higher than standard definition on a visual display such as LCD or plasma. There are three common formats of High Definition starting with 720p (1280x720 pixels), then 1080i (1080 lines of interlaced horizontal resolution), and then the best is 1080p (1920x1080 pixels). You'll notice that the ones ending in "p" (progressive scan) are stated in terms of pixel resolution, whereas a number ending in "i" (interlaced) is not reliant on vertical resolution (number of pixels across the width of the screen), but rather it is a higher resolution form of PAL or NTSC.
"HD" is commonly used as a label for the 720p and 1080i formats, whereas "Full HD" is a proxy term which was unofficially adopted by the industry to denote the higher resolution 1920x1080. So displays with the "Full HD" label should be expected to be able to resolve native 1920x1080 images pixel-for-pixel, from sources such as Blu-ray and HD-DVD. Note that a display with 1080pixels high but NOT 1920 pixels wide should not be labelled as "Full HD".
Q2. Will any "HDMI 1.3" labelled cable be suitable for use with "Full HD"?
A2. HDMI Licensing recently introduced new labelling guidelines relating to this issue. Over the coming several months the most reputable HDMI cable manufacturers (ie: the licensed ones) will follow these guidlines by labelling cables as either "Standard" or "High Speed". Both are part of the 1.3 specification, so please don't assume that all HDMI 1.3 cables are equal. "Standard" referes to cables that are guaranteed to pass 720p/1080i as a minimum, but may in some cases also pass 1080p by application only (refer to the manufacturers' disclosures), but this is not required for certification. "High Speed" on the other hand will pass the full potential of HDMI 1.3 with full 1080p, Deep colour and the new HD Audio formats etc.
So why have two levels you ask? Surely this just confuses the market... Well, suggesting that there should be just one level - the top one - is like suggesting that all Holdens and Fords should be abolished, and that everybody should buy Mercedes Benz and BMW instead. ...this of course is just not going to happen. You only need High Speed HDMI if you have a top-end system with genuine 1080p. The reality is that most consumers won't, opting for the more common and economical 1366x768 resolution (WXGA) plasmas and LCDs and inputing 720p or 1080i at best.
Q3. Which type of cable do I need for my application?
A3. Fortunately this one is quite simple. Regardless of the sources that you are running, use a Standard HDMI cable if your display is anything less than 1920x1080 resolution, and use a High Speed HDMI cable if your display is of native 1920x1080 resolution. The hard part right now is determining what cables are Standard and which ones are High Speed - this is something for which you must rely on the manufacturer.
NOTE: The use of low end upscalers that offer a boosted resolution from Standard to 1080i or 1080p should be treated with caution. Unless a percetible difference in picture quality results, upscalers can produce more problems in cable compatibility and bandwidth. Likewise, if your display is less than 1920x1080 resolution, set all source devices to output 720p or 1080i maximum (whichever looks better on your display), and only use 1080p where the display is native 1920x1080. Why? Because 1080p is much harder to pass through a cable, and you need either a high end Standard cable or preferably a High Speed cable to support it, and for no end benefit since the display will just step it back a notch anyway...
For more frequently asked questions, please visit HDMI Australia
Date
Tuesday 06 Nov 2007 - Sunday 15 Nov 2009
