HDMI is the latest connection type found on all new modern TV’s, most modern Home Theatre amplifiers and many computer monitors. But why is it important to buy equipment with HDMI connections, and how much do you need to spend on HDMI cables?
HDMI stands for High Definition Multimedia Interface, and was designed to be a backwards-compatible replacement for the DVI interface commonly found on computer monitors. The standard called for a single cable that could carry a high-definition video stream, up to eight channels of digital audio and a single Consumer Electronics Control Signal. Its primary purpose was to become the standard connection between all consumer AV devices and computer displays. Today, all new projectors and televisions will come with at least one HDMI connection and usually more to receive hi-definition video digital cinema.
Perhaps the most significant part of the HDMI specification is the support for HDCP, High-bandwidth Digital Copy Protection. HDCP-protected content such as Blu-Ray movies can only be decoded by licensed HDCP players, and any devices that connect to the player, must also be HDCP certified, or the player will only output a standard-definition signal. For this reason, when buying high-definition projectors, televisions or other devices, it’s best to make sure they have HDMI connections and are HDCP certified.
Be careful when hooking up your home theatre system. It is not possible to have a HDMI connection to your amplifier, and then a component connection to your projector, as the HDCP protocol will prevent the player from sending a hi-def video signal due to the final connection not being via HDMI. It is possible, however, to connect your blu-ray player or cable box to your TV by HDMI and use a separate connection, such as a digital optical cable, to send audio to your amplifier.
HDMI carries both audio and video. This means only a single cable is required to connect a TV to your Blu-ray player or cable box. If you use a separate Home Theatre amplifier, then the player and cable box can first be connected to the amplifier, which is then connected by another HDMI cable to your TV. In this setup, the amplifier uses the audio channels and passes the video channel on to the TV. If you use the approach, look for a high-quality Home Theatre amplifier, with several HDMI inputs for all your sources, which also support HDCP.
Finally, a few words on buying HDMI cables. The prices of HDMI cables can vary enormously, with certain branded cables costing 10x the price of the same length unbranded cable. In practice, HDMI cable quality has very little impact on the quality of the audio and video transmitted through it. Unlike previous home video cable standards, HDMI is an all-digital connection, so the signals are much more resistant to interference and noise. For short cable lengths, almost any HDMI cable will be fine. Longer lengths can be more susceptible to connection dropouts due to HDCP signal loss, so consider spending a little extra on these, but keep away from the most expensive brands as they offer very little extra benefit.