HDMI – YOUR QUESTIONS ANSWERED

HDMI (High Definition Multimedia Interface) is essentially an interface that can transmit digital signals between two devices. For example, computer input or DVD Player to a display device. As a technology, HDMI has been around for some time, but we find there is still some confusion surrounding its capabilities, benefits and shortfalls.

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Here we answer some common questions…

Q.  What are the advantages of using a HDMI cable over other interfaces?

A. The key benefit of HDMI is its ability to transport a high bandwidth of data (video, audio and now 3D and Ethernet) using a single cable.  For the average consumer, the ability to connect their TV and DVD player with just one cable certainly makes setting up a home entertainment system less daunting. From a commercial perspective, system designers consider HDMI, along with other interfaces including VGA and DVI in determining the most appropriate interface for a project.

The key benefits HDMI offers over analogue interfaces are:

  • Increased quality of picture with better contrast and colour saturation
  • Easy to use with a range of features transmitted via a single connector
  • By allowing your devices to “talk” to each other, the AV system is more intuitive and can be controlled by a single remote.

Q. Is it important to make sure the HDMI version of your devices match?

A. HDMI versions are ‘backward compatible’ so a device outputting HDMI 1.3 will generally transmit effectively to a HDMI 1.4 input. In conjunction with looking at the version number, it is also recommended that you look at the features supported by the version and ensure the feature you want is specified in every device and cable in the system.

Q.  Are all HDMI cables the same and do they all transmit Full HD 1080p and Deep Colour?

A. There are five certifications for HDMI Cabling, with the two most well known being:

  • Standard HDMI: performs at speeds of up to 2.25Gbps and will support 720p/1080i signals.
  • High Speed HDMI: performs at speeds of up to 10.2Gbps and will support features such as HD 1080p and Deep Colour.

Standard HDMI with Ethernet, High Speed HDMI with Ethernet and Standard Automotive are the other HDMI certifications introduced to support features of HDMI 1.4.

Like all formats, cable quality does vary between brands. It is important to buy a cable that is HDMI certified to ensure quality, longevity and increase resistance of interference from other systems.

Advice from a trusted source is essential to ensure your cable does not let your system down.

Q. Am I able to run HDMI run over long distances reliably? 

A. HDMI cables in their original form do not tackle the problem of signal loss over long cable runs any better than DVI or VGA. Most cable lengths of more than 5-10 metres will inevitably lose data from source to output.

InSight Systems has encountered the challenge of running long cable lengths in several commercial applications including projects at Swinburne University of Technology and Box Hill TAFE. Both clients needed to maintain exceptional signal quality over long distances so to avoid any loss in data, InSight utilise Extron’s Twisted Pair technology.  The Extron solution takes the VGA, DVI or HDMI signal, converts and extends it over shielded, low skew UTP cabling. A transmitter and receiver pair is employed for each cable length, ensuring the signal quality is maintained from source to display.

At the end of the day, it is always best to get good advice from a trusted source.