HDMI is no longer strange for us now; it is everywhere in your home, your HD TVs, HD media players, Set-Top Box, your HD displays, your HD cameras, your HD recorders and so on. We couldn’t ignore it in our daily life. Thus here comes the question, do you know what’s the maximum length you can run the HDMI cables? You might have no idea. Yes, most of us would never have thought about this question. However, there is the case that we need extend our HD devices to a longer distance, such as extend the HD signals of your HD media player from one room to another room, then do you know the max length you can go. So let’s check the case.
There are two categories of HDMI as defined by the HDMI organization, “standard HDMI cables” and “high speed HDMI cables”:
Standard (or “category 1″) HDMI cables have been tested to perform at speeds of 75Mhz or up to 2.25Gbps, which is the equivalent of a 720p/1080i signal.
High Speed (or “category 2″) HDMI cables have been tested to perform at speeds of 340Mhz or up to 10.2Gbps, which is the highest bandwidth currently available over an HDMI cable and can successfully handle 1080p signals including those at increased color depths and/or increased refresh rates from the Source. High-Speed cables are also able to accommodate higher resolution displays, such as WQXGA cinema monitors (resolution of 2560 x 1600).
The HDMI specification specifies required performance of a given cable, but does not govern the length as long as the cable meets the given requirements. So how far of an HDMI cable can you run from your video source to your television set? The professional technical support from VVdeals recommends 25 feet as a practical limit for their high speed cables to carry both a 1080p and 3D signal. After 25ft they are no longer certified for high speed. And with the longer distance increase, the quality for the videos would decrease.
Standard speed cables can carry 1080p but it depends on the device is why we only list them as 1080i/720p. Many newer devices though if all you want is 1080p can achieve that with standard speed cables, you only really need a standard speed cable if you are running both 3D and 1080p.
The specifications on HDMI cables themselves as a technology (disregarding manufacturer specs) do not give an explicit limit in cable length. However, there is another way to know the limits on cable length. The HDMI Authorized Testing Centers give certificates for cables based upon speeds, reliability, and cable length. The longest cables to successfully pass the ATC tests for reliability and speed are around 45 feet long. These pass the HDMI 1.3a tests. While there are many 50 feet cables on the market, these generally may not have passed compliance testing, and further research should be done to ensure reliability.
There are cables that use an amplifier or repeater to compensate for high frequency data losses over the increased length of the cable. These can work excellently and maintain quality, but are not always the best option.
For sakes of practicality, any cable that is approximately 50 feet or less in length will work reliably. Economical cables and lower quality manufactured cables can maintain 780p or 1080i. Premium cables under 50 feet will be able to reliably achieve 1080p. However the device specifications and quality also play a role in the data transfer rates and reliability. Some devices won’t be able to utilize the high-speed capacity of certain cables and could produce losses with increasing lengths even with an excellent quality cable. Therefore, it is wise to consult with specific cable specs and device specs to determine the quality needed and what if any losses will be over certain lengths. If cables exceeding this “maximum” capacity are needed, cables with the amplifiers or extender are available.
Then think of the “25 feet” as the magic barrier. So what to do if you need to go longer distances and insist on carrying a 1080p signal without sacrifice of signal loss? All hope is not lost. You have a couple of alternative solutions including more HDMI cables and cat6 Ethernet cables. As HDMI cables are more expensive and the quality would decrease when the distance is longer. So Cat5e or cat6 network cables would be highly recommended. CAT6 ethernet cables which allow for runs up to a whopping 330 feet. You can use a HDMI network extender to transmit HD signals to a longer distance as long as you can. Of course, if you don’t like wires in a mess, a wireless HDMI extender would be an good option.
Anyway just make sure that your cable matches your application and that all specs are up to speed when you’re going for longer distance transmission.