(High-Definition Multimedia Interface) is an audio video interface for transmitting uncompressed digital data between high definition devices such as HD DVD players, HD satellite boxes and High Definition Televisions. It offers crystal clear, all-digital, audio and video signal in a single cable.
Versions of HDMI.
There are various versions of HDMI cable, v1.0, v1.2, v1.3a, v1.3b, v1.4. The versions of 1.3 (a & b) relate to the testing specification to which the cable has been certified and do not necessarily offer increased functionality.
Version 1.4 is the latest most up to date specification which includes an Ethernet channel to be compatible with IP enable equipment. Version 1.4 also supports 3D and has resolutions up to 4096 X 2160. The HDMI organisation announced new regulations regarding the labelling of version 1.4 cables, these regulations prohibit manufacturers from using the phrase “1.4” on the cable or packaging, this was introduced to aid end stage users who were becoming increasingly confused by the version numbers. The latest version 1.4 is known as “High Speed HDMI Cable With Ethernet”.
All newer versions are fully backwards compatible with older versions. The HDMI licensing authority is currently working with manufacturers to focus on features and de-emphasize version numbers to help reduce customer confusion. The features fall into three categories:
Standard and High Speed refer to the two types of HDMI cables and can be used with 1080i and 780p devices. High Speed HDMI cables can be used for 1080p devices such as Blu-ray players and PS3 gaming consoles.
Deep Colour, this refers to Television and monitors that can display more colours than standard.
X.V Colour, this offers an expanded, or wider HDMI Cable in Australia range of colours which can not usually be displayed on a TV.
What to Look For.
When buying HDMI cables there are certain things to look out for. Ferrite EMI Suppressors are important for reducing electro magnetical interference, they are round barrel shaped coils usually found on either end of the cable. Shielded or even double and triple shielded cables improve quality. Gold plated connectors don not have a massive effect on image quality, but they do reduce oxidization.
HDMI cable specification does not define a maximum cable length, but due to attenuation there is a limit as to how long a HDMI lead can successfully transmit the signal. Build quality and the material greatly affect the overall length an HDMI cable can be used without losing quality. A safe limit for no loss of quality would be around 7.5M. Higher quality cables can be used up to 20M. Amplifiers are available to increase the distance a signal can travel without deteriorating.