HDMI (High-Definition Multimedia Interface) is a brand of proprietary digital interface used to transmit high-quality video and audio signals between devices. It is commonly used to connect devices such as televisions, computer monitors, projectors, gaming consoles, and personal computers. HDMI supports uncompressed video and digital audio either compressed or uncompressed, allowing a single cable to carry all audiovisual signals. Introduced in 2003, HDMI largely replaced older analog video standards such as composite video, S-Video, and VGA in consumer electronics. It was developed based on the CEA-861 standard, which was also used with the earlier Digital Visual Interface (DVI). HDMI is electrically compatible with DVI video signals, and adapters allow interoperability between the two without signal conversion or loss of quality. Adapters and active converters are also available for connecting HDMI to other video interfaces, including the older analog formats, as well as digital formats such as DisplayPort. HDMI has gone through multiple revisions since its introduction, with each version adding new features while maintaining backward compatibility. In addition to transmitting audio and video, HDMI also supports data transmission for features such as Consumer Electronics Control (CEC), which allows devices to control each other through a single remote, and the HDMI Ethernet Channel (HEC), which enables network connectivity between compatible devices. It also supports the Display Data Channel (DDC), used for automatic configuration between source devices and displays. Newer versions include advanced capabilities such as 3D video, higher resolutions, and expanded color spaces. The Audio Return Channel (ARC) and Enhanced Audio Return Channel (eARC) allow audio to be sent from a display back to an audio system over the same HDMI cable. Smaller connector types, Mini and Micro HDMI, were also introduced for use with compact devices like camcorders and tablets. As of January 2026, nearly 14 billion HDMI-enabled devices have been sold worldwide, making it one of the most widely adopted audio/video interfaces in consumer electronics.
History The HDMI founders were Hitachi, Panasonic, Sanyo (as a Panasonic affiliate), Philips, Silicon Image (now Lattice Semiconductor), Sony, Thomson (now Vantiva), and Toshiba. Intel contributed the HDCP copy protection system. The new format won the support of motion picture studios Fox, Universal, Warner Bros. and Disney, along with content distributors DirecTV, EchoStar (Dish Network) and CableLabs. The HDMI founders began development on HDMI 1.0 on April 16, 2002, with the goal of creating an AV connector that was backward-compatible with DVI. At the time, DVI-HDCP (DVI with HDCP) and DVI-HDTV (DVI-HDCP using the CEA-861-B video standard) were being used on HDTVs. HDMI 1.0 was designed to improve on DVI-HDTV by using a smaller connector and adding audio capability, enhanced Y′CBCR capability, and consumer electronics control functions. The first Authorized Testing Center (ATC), which tests HDMI products, was opened by Silicon Image on June 23, 2003, in California, United States. The first ATC in Japan was opened by Panasonic on May 1, 2004, in Osaka. The first ATC in Europe was opened by Philips on May 25, 2005, in Caen, France. The first ATC in China was opened by Silicon Image on November 21, 2005, in Shenzhen. The first ATC in India was opened by Philips on June 12, 2008, in Bangalore. The HDMI website contains a list of all the ATCs. According to In-Stat, the number of HDMI devices sold was 5 million in 2004, 17.4 million in 2005, 63 million in 2006, and 143 million in 2007. HDMI has become the de facto standard for HDTVs, and according to In-Stat, around 90% of digital televisions in 2007 included HDMI. In-Stat has estimated that 229 million HDMI devices were sold in 2008. On April 8, 2008, there were over 850 consumer electronics and PC companies that had adopted the HDMI specification (HDMI adopters). On January 7, 2009, HDMI Licensing, LLC announced that HDMI had reached an installed base of over 600 million HDMI devices. In-Stat estimated that 394 million HDMI devices would sell in 2009 and that all digital televisions by the end of 2009 would have at least one HDMI input. On January 28, 2008, In-Stat reported that shipments of HDMI were expected to exceed those of DVI in 2008, driven primarily by the consumer electronics market. In 2008, PC Magazine awarded a Technical Excellence Award in the Home Theater category for an "innovation that has changed the world" to the CEC portion of the HDMI specification. Ten companies were given a Technology and Engineering Emmy Award for their development of HDMI by the National Academy of Television Arts and Sciences on January 7, 2009. On October 25, 2011, the HDMI Forum was established by the HDMI founders. Also on the same day HDMI Licensing, LLC announced that there were over 1,100 HDMI adopters and that more than 2 billion HDMI-enabled products had shipped since the launch of the HDMI standard. On January 8, 2013, HDMI Licensing, LLC announced that there were over 1,300 HDMI adopters and that over 3 billion HDMI devices had shipped since the launch of the HDMI standard. The day also marked the 10th anniversary of the release of the first HDMI specification. As of January 2021, nearly 10 billion HDMI devices had been sold.
Specifications The HDMI specification defines the protocols, signals, electrical interfaces and mechanical requirements of the standard. The maximum pixel clock rate for HDMI 1.0 is 165 MHz, which is sufficient to allow 1080p and WUXGA (1920×1200) at 60 Hz. HDMI 1.3 increases that to 340 MHz, which allows for higher resolution (such as WQXGA, 2560×1600) across a single digital link. An HDMI connection can either be single-link (type A/C/D) or dual-link (type B) and can have a video pixel rate of 25 MHz to 340 MHz (for a single-link connection) or 25 MHz to 680 MHz (for a dual-link connection). Video formats with pixel rates below 25 MHz (like 480i at 13.5 MHz) are transmitted over TMDS links using a pixel-repetition scheme.
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