HDMI (High-Definition Multimedia Interface) cables have become a standard for connecting high definition video devices. They transmit uncompressed video data and compressed or uncompressed digital audio data from an HDMI-compliant source device to compatible screens. Most TVs, computer monitors, projectors, etc. are equipped with at least one HDMI port.
HDMI cables have cleaned up wire clutter behind our TVs, computer monitors etc. They allow for a quick and easy connection of a vast range of devices and support the HD revolution. This all in one cable has changed the way we connect devices to screens, but it to has its limitations.
Similar to other video, audio and data cables, HDMI cables present signal degradation at longer lengths. 50 feet is considered to be the max reliable distance for uninterrupted signal. Most stores carry up to 25 feet long HDMI cables.
When the TV and other AV devices are in close proximity to one another, there is no need for a longer HDMI cable. The proximity of the devices allow for use of shorter cables, usually around 6 feet long at most.
The issue starts with longer distances. A wall hung flat screen TV or HD home theater digital projector may call for some in wall wiring. In some cases the wires are run from one room to another (AV closet). When fishing wires up into ceilings or over door frames, cable lengths start to add up.
In these cases, there are a few ways to go.
HDMI over Cat6
With the use of a balun extender, the HDMI signal is passed along to one or more Cat5e or Cat6 cable. Another balun extender passes the signal back to an HDMI cable at the other end. The HDMI connects directly to the device and display screen on each end. These HDMI balun extenders lengthen signal distance up to 150 feet.
Most importantly, HDMI over Cat6 preserves the quality of video and audio signals.
HDMI over Coaxial
Adding coaxial cables in the mix will extend signal distance up to 300 feet. The challenge with coaxial cables lays in the need for multiple cables (minimum two, usually four), which are usually not already installed in the home. This changes the budget, which is something to think about.
When in wall wiring is not an option (for example renters may not be allowed to run cables in wall), wireless is the way to go. Wireless HD systems are also limited by distance, with a usual max broadcast distance of 50 feet. Other limitations of wireless HD include image degradation and unpredictable signal interruptions. Additionally, going wireless is more costly than a wired solution.
In the interest of assuring best quality and saving on cost carefully asses your needs. If your runs are 50 feet or less, HDMI will surely be the most reliable and more cost effective way to go. HDMI can be easily fished through walls. It cannot be cut to specific lengths, so you will need to buy longer cable and leave the extra in-wall. Still, HDMI may be the best solution overall.