HDMI was created in 2002 as a way to bring audio and video into the digital age. As opposed to its predecessors VGA, RCA, and others that require a mess of multiple connections and wires, HDMI is a one-cable for-all solution that transports both video and audio over one connection.
Here's the technical definition of HDMI from Wikipedia:
HDMI is a proprietary audio/video interface for transmitting uncompressed video data and compressed or uncompressed digital audio data from an HDMI-compliant source device, such as a display controller, to a compatible computer monitor, video projector, digital television, or digital audio device.
There are 5 connector types and the most common HDMI type is HDMI Type A with 19 pins.
History of HDMI - A TimeLine
Here's a condensed history of HDMI from an obscure new technology in 2002 to its adoption by billions of consumers in less than a decade.
- April 16, 2002 - The HDMI founders began development on HDMI 1.0 with the goal of creating an AV connector that was backward-compatible with DVI (Digital Visual Interface). HDMI was also created as a way to transport both video and audio over a single cable. DVI was the standard at the time and only transported visual info.
- HDMI was designed in December 2002 by the founders Hitachi, Panasonic, Philips, Silicon Image, Sony, Thomson, and Toshiba. HDMI 1.0 had the support of motion picture producers Fox, Universal, Warner Bros. and Disney, along with system operators DirecTV, EchoStar (Dish Network) and CableLabs.
- 2004 - HDMI started to appear in consumer electronics.
- 2011 - The HDMI Forum is established by the HDMI founders to create an open organization so that interested companies can participate in the development of the HDMI specification. All future development of the HDMI specification take place in the HDMI Forum and are built upon the HDMI 1.4b specification. Also on the same day, HDMI Licensing, LLC announced that there were over 1,100 HDMI adopters and that over 2 billion HDMI-enabled products had shipped since the launch of the HDMI standard.
- 2021 - Over 10 billion HDMI devices have been sold.
HDMI functions through a technology called transition-minimized differential signaling (TDMS). TDMS is a method of transferring data like audio and video from one location to another. As information travels down the cable from one device to another, TDMS is able to protect the information from degradation.
An HDMI cable is composed of four shielded twisted pairs plus seven separate conductors. As the information is transmitted, one of the twisted pairs of cables carries the signal itself while the other carries the inverse copy of the signal that is in transmission. The difference between these signals is measured as it arrives at the receiving device and this difference is then used to account for signal loss. High-quality audio and video is the result!
HDMI uses three physically separate communication channels, which are the DDC (data display channel), TMDS, and the optional CEC (Consumer Electronics Control). HDMI 1.4 added ARC (audio return channel) and HEC (HDMI Ethernet channel).
HDMI can be used in a number of applications including but not limited to:
- Home TV, theatre, and Blu Ray
- Computer monitor
- Raspberry Pi monitor
- Automotive entertainment
- Digital cameras and cam corders
Skip to the section "Finding the right HDMI Cable for You" to see the specifics of cable recommendations for these different applications.
HDMI 2.1 is the most up-to-date version of HDMI at the time of this writing. I will cover the different versions of HDMI in the next section. Here are the benefits and specs of using HDMI 2.1:
- Supports 8K resolution at 60 frames per second
- Supports 4K resolution at 120 frames per second
- Up to 48 GBPS (Gigabytes per second)
- Great for daisy-chaining (connecting multiple monitors)
Of course, not all devices are compatible with HDMI 2.1 but I will talk about what that means for you and what cables will work best for your setup in the coming pages.