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HDMI

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HDMI, which stands for High-Definition Multimedia Interface, is a proprietary digital interface.

HDMI-Kabel
HDMI-Kabel

It is used to transmit high-quality video and audio signals between various electronic devices. This technology allows a single cable to carry both uncompressed video and digital audio signals. It is essential for connecting televisions, computer monitors, projectors, gaming consoles, and personal computers. Because it can handle both sound and picture through one connection, it has become a global standard.

HDMI.socket
HDMI.socket

Today, it is one of the most widely adopted audio/video interfaces in the consumer electronics industry.

The mechanism of HDMI relies on three physically separate communication channels to manage data.

HDMI wires
HDMI wires

The first is the Display Data Channel (DDC), which is a VESA standard. This channel uses the Enhanced Display Data Channel (E-DDC) to allow a source device to talk to a display. Through this, the source reads E-EDID data to learn which audio and video formats the display can accept. The second channel is Transition-minimized differential signaling (TMDS).

HDMI Connector Pinout
HDMI Connector Pinout

TMDS interleaves video, audio, and auxiliary data using three specific packet types. It uses a video data period to transmit pixels of an active video line. This is followed by a data island period, which occurs during horizontal and vertical blanking intervals. During this island period, the system transmits audio and auxiliary data in packets. Finally, a control period occurs between the video and data island periods.

HDMI technology includes several distinct features and specialized communication protocols. One important feature is Consumer Electronics Control (CEC), which allows devices to control each other using a single remote. Another is the HDMI Ethernet Channel (HEC), which enables network connectivity between compatible devices. There is also the Audio Return Channel (ARC), introduced with the HDMI 1.4 standard.

HDMI 1.4 with Audio Return Channel
HDMI 1.4 with Audio Return Channel

ARC allows audio to be sent "upstream" from a display back to an audio system. Newer versions also support the Enhanced Audio Return Channel (eARC). Beyond basic signals, HDMI supports advanced capabilities like 3D video, higher resolutions, and expanded color spaces. It also provides the Display Data Channel (DDC) for automatic configuration between devices.

The history of HDMI began with a large group of founding companies.

550 S. Winchester Blvd
550 S. Winchester Blvd

These founders included Hitachi, Panasonic, Sanyo, Philips, Silicon Image, Sony, Thomson, and Toshiba. Intel contributed the High-bandwidth Digital Content Protection (HDCP) system for copy protection. Development on HDMI 1.0 began on April 16, 2002. The goal was to create an AV connector that remained backward-compatible with the Digital Visual Interface (DVI).

DVI-HDMI-Adapter
DVI-HDMI-Adapter

HDMI was designed to improve upon DVI-HDTV by using a smaller connector and adding audio. The first Authorized Testing Center (ATC) opened in California on June 23, 2003. Subsequent testing centers opened in Japan, France, China, and India to ensure product quality.

The growth of HDMI has been massive in terms of market adoption and sales.

HDMI Connector Types
HDMI Connector Types

In 2004, only 5 million HDMI devices were sold worldwide. By 2007, annual sales reached 143 million units. By 2008, shipments of HDMI were expected to exceed those of DVI. In 2009, the installed base of HDMI devices reached over 600 million. By 2013, the number of shipped HDMI devices exceeded 3 billion. Today, nearly 14 billion HDMI-enabled devices have been sold globally. This massive scale shows how much the technology has changed consumer electronics.

There are several different physical connector types used depending on the device size.

Mini micro HDMI Stecker by NicoJenner
Mini micro HDMI Stecker by NicoJenner

The standard connector is known as Type A. For more compact electronics, smaller versions called Mini and Micro HDMI were introduced.

MicroHDMI Rpi4
MicroHDMI Rpi4

These smaller plugs are used for devices like tablets and camcorders. Even laptops use these interfaces, such as the port found on an Acer Swift 3.

Acer Swift 3 rear-left edge
Acer Swift 3 rear-left edge

Because HDMI is electrically compatible with DVI, adapters can be used to connect the two. This allows for interoperability between different video interfaces without losing signal quality.

HDMI connects many different fields of technology and standards together. It is built upon the CEA-861 standard, which was also used for earlier DVI interfaces. This connection to established standards ensures that different brands of equipment can work together. The interface also interacts with complex color science, such as the sRGB color space. It supports various audio formats, including uncompressed PCM and compressed streams like Dolby Digital. By combining video, audio, and control data, HDMI acts as a central hub for modern digital entertainment systems.

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🖼️ Images & Media (14)
File:HDMI Connector Pinout.svg
HDMI Connector Pinout.svg
File:DVI-HDMI-Adapter.jpg
DVI-HDMI-Adapter.jpg
File:Adapter dvi hdmi S7302224 wp.jpg
Adapter dvi hdmi S7302224 wp.jpg
File:HDMI Connector Types.png
HDMI Connector Types.png
File:Mini micro HDMI Stecker by NicoJenner.jpg
Mini micro HDMI Stecker by NicoJenner.jpg
File:HDMI.socket.png
HDMI.socket.png
File:MicroHDMI Rpi4.jpg
MicroHDMI Rpi4.jpg
File:HDMI-Kabel.jpg
HDMI-Kabel.jpg
File:HDMI wires.jpg
HDMI wires.jpg
File:550 S. Winchester Blvd.jpg
550 S. Winchester Blvd.jpg
File:HDMI 1.4 with Audio Return Channel.png
HDMI 1.4 with Audio Return Channel.png
File:Acer Swift 3 rear-left edge.jpg
Acer Swift 3 rear-left edge.jpg

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