Introduction to Video Cable

In the video world over the past 20 years there have been many, many different types of cables and connections used to pass signal from one medium to another. From composite video to VGA and DVI, and now at SDI and HDMI. But while we have heard of these cables, what are they? And what do they do? Today we’re going to talk about HDMI and SDI. 

Let’s start with HDMI cables. HDMI stands for High Definition Multimedia Interface and is the most frequently used HD signal for transferring both high definition video and audio over a single cable. HDMI is used for connecting devices such as TV’s, wireless presentation devices like an AppleTV or Klikboks (read HERE) and is considered a consumer-level video cable. Most likely you have one or two laying around your home. One of the big advantages of HDMI at the consumer level is the simple fact that it is a single cable solution for combining both video and audio. It replaces many of the analog solutions which required separate video and audio cables. One of the big disadvantages is that you can only run most HDMI cables up to 25’ making it a less desirable option in professional settings.

This brings us to SDI. SDI stands for Serial Digital Interface and is a standard video signal used by professional, broadcast grade cameras. SDI cable has the ability to transmit HD video signal over a much further distance than HDMI. SDI also has the ability to pass audio as well. Now SDI cables are made up of two components, 75ohm coaxial cable and BNC connectors. Now, not all SDI cables are the same. Different cables can carry different quality signals over specific distances. Just because a cable fits or is long enough, doesn’t mean it will work, or that it will work properly! The higher the quality of the video signal you are sending requires you to either go a shorter distance, but usually you need to use a higher-grade cable too. There is a lot about SDI. SDI video signal, the different qualities, and some of the solutions that SDI offers are a few, but we’ll have to get to those later.