What is HDMI?

What is HDMI? -As you have already heard, HDMI, which comes from High-Definition Multimedia Interface, is the most advanced digital audio and video connector existent today on the market. A single cable provides not only High Definition video content on your display, but also outstanding sound quality with 8-channels digital audio at 192 kHz sample rate with 24 bits/sample. It’s the best and an affordable solution for connecting your HD-enabled devices such as HD DVD player or Blu-ray player, to your High Definition TV, because this type of cables can be found at low prices of around $10. Experts recommend you to get the cheapest HDMI cables you can find in stores and avoid expensive solutions, as long as all enable the same high-quality content.

How to recognize HDMI cables? Well, HDMI cables have 19-pin connectors and look like in this image, where you can see the differences between it and the other cables used today for video.



Coax or RF cables are for digital and analog video/audio, Composite Video supports analog video same as the S-Video, while the Component Video is that cable with 3 Red-Green-Blue connectors for both analog and digital video signals. DVI is the most advanced cable after HDMI, and supports only High-Definition digital video signals, requiring additional audio connectivity like all the other cables mentioned.

HDMI instead, brings all together via a single cable, and its connector’s pins have different functions such as carrying Transition Minimized Differential Signaling data channels for DVI and HDMI high-speed digital data, enabling signals synchronization, sending command and control data between connected devices, enabling communication of Extended Display Identification Channel information between the 2 connected devices, carrying low-voltage power supply, and monitoring power up/down and plug/unplug events.



Even if there are different versions available, there is the same type of cable. They feature different bandwidth increase levels and additional capabilities. For example, HDMI 1.0 released in 2002 has a bandwidth of 4.9Gbit/sec, with 3.96 Gbit/sec for video and 8-channel audio. HDMI 1.1 appeared in 2004 with additional support for DVD Audio, while one year later, HDMI 1.2 brought support for Super Audio CDs, HDMI Type A connector for PC sources, support for native sRGB color, and support for loq-voltage sources. In the same year, HDMI 1.2a came with Customer Electronic Control features. In 2006, HDMI 1.3 enabled bandwidth up to 10.2 Gbit/sec with 340 MHz, added Deep Color support, Audio video sync capability, support for Dolby TrueHD and DTS-HD Master Audio streams, and the Type C mini connector for portable devices. 2 years ago, HDMI 1.3a adjusted some features, same as with HDMI 1.3b.

Another aspect is the cable length. All types of cables used for audio, video and networking can be installed up to a recommended length such as 100 meters, to avoid signal loss. Additional devices, such as repeaters, are meant to amplify the information on the cables after that length limit and currently the best solution is, of course, optical fiber, which can be used without amplifiers on a distance of much over 500 meters.

In the case of HDMI the maximum cable length depends on construction and materials it is made of. With this occasion we’ll also find the answer to the question “which HDMI cable is better and why?” because we will see that there are 2 types of HDMI cables introduced by the HDMI 1.3 standard. Category 1 supports 1080i/720p with 74.5 MHz, and Category 2 was tested at 4600p with 340 MHz, so yes, you could say the second type is better because it enables High Definition imaging on higher-resolution displays like Wide Quad eXtended Graphics Array of 2560×1600 pixels and with a 16:10 aspect ratio. If you have smaller monitors, then you don’t need to go for it, but rather choose the HDMI Category 1 cable type for a widescreen aspect ratio of 16:9, 1920 pixels horizontal resolution, and 1920 × 1080 frame resolution of up to 2.07 million pixels.
About their length, let’s say that if a Category 1 cable is made of materials like 24 AWG conductors it can reach 15 meters, and when extenders are used, cables can exceed 100 meters if based on fiber optics technology.



Today, devices with HDMI support include television panels, computer graphic cards, mainboards, the PlayStation 3 gaming console, Blu-ray players, high-end multimedia projectors, and some portable media players. All are available at higher prices compared to non-HD systems, but the image quality they enable is amazing and totally different than what you were used with before.

(Sources: Philips; Wikipedia)

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