HDMI

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.

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. 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 YCbCr| capability, and consumer electronics control functions. 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 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.

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.

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 60Hz. 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. On July 15, 2013, the CEA announced the publication of CEA-861-F, a standard that can be used by video interfaces such as DVI, HDMI, and LVDS. CEA-861-F adds the ability to transmit several Ultra HD video formats and additional color spaces. As such, any closed caption stream must be decoded and included as an image in the video stream(s) prior to transmission over an HDMI cable to appear on the DTV. This limits the caption style (even for digital captions) to only that decoded at the source prior to HDMI transmission. This also prevents closed captions when transmission over HDMI is required for upconversion. For example, a DVD player that sends an upscaled 720p/1080i format via HDMI to an HDTV has no way to pass Closed Captioning data so that the HDTV can decode it, as there is no line 21 VBI in that format.

Communication channels

HDMI has three physically separate communication channels, which are the VESA DDC, TMDS and the optional CEC. by using only one of their remote controls (for example by controlling a television set, set-top box, and DVD player using only the remote control of the TV). CEC also allows for individual CEC-enabled devices to command and control each other without user intervention. CEC wiring is mandatory, although implementation of CEC in a product is optional.

HDMI Ethernet and Audio Return Channel

Introduced in HDMI 1.4, HDMI Ethernet and Audio Return Channel (HEAC) adds a high-speed bidirectional data communication link (HEC) and the ability to send audio data upstream to the source device (ARC). HEAC utilizes two lines from the connector: the previously unused Reserved pin (called HEAC+) and the Hot Plug Detect pin (called HEAC−). If only ARC transmission is required, a single mode signal using the HEAC+ line can be used, otherwise, HEC is transmitted as a differential signal over the pair of lines, and ARC as a common mode component of the pair. ARC supports stereo PCM and compressed codecs Dolby Digital, Dolby Digital Plus and DTS up to 5.1 channels, with Dolby Atmos metadata in Dolby codecs.

eARC (Enhanced Audio Return Channel) was introduced in 2017 with the HDMI 2.1 standard. eARC has higher bandwidth (37 Mbps) and adds support for uncompressed surround sound, Dolby TrueHD and DTS-HD Master Audio passthrough with support for up to 32 channels. eARC requires an "Ultra High Speed", "Premium High Speed with Ethernet", or "High Speed with Ethernet" HDMI cable.

HDMI Ethernet Channel (HEC)

HDMI Ethernet Channel technology consolidates video, audio, and data streams into a single HDMI cable, and the HEC feature enables IP-based applications over HDMI and provides a bidirectional Ethernet communication at .

Compatibility with DVI

thumb|alt=An adapter with a DVI receptacle connector to HDMI plug connector.|An adapter with HDMI (male, right) and DVI (female, left) connectors

thumb|alt=An adapter with an HDMI receptacle connector to DVI plug connector with a close up of the HDMI connector.|An adapter with DVI (male, rear, not visible) and HDMI (female, front) connectors

HDMI is backward compatible with single-link Digital Visual Interface digital video (DVI-D or DVI-I, but not DVI-A or dual-link DVI). No signal conversion is required when an adapter or asymmetric cable is used, so there is no loss of video quality. A further complication is that there is a small amount of display equipment, such as some high-end home theater projectors, designed with HDMI inputs but not HDCP-compliant.

Any DVI-to-HDMI adapter can function as an HDMI-to-DVI adapter (and vice versa). Typically, the only limitation is the gender of the adapter's connectors and the gender of the cables and sockets it is used with.

Features specific to HDMI, such as remote-control and audio transport, are not available in devices that use legacy DVI-D signalling. However, many devices output HDMI over a DVI connector (e.g., ATI HD 2000-series and Nvidia GTX 200-series video cards), and some multimedia displays may accept HDMI (including audio) over a DVI input. Exact capabilities beyond basic compatibility vary. Adapters are generally bi-directional.

Content protection (HDCP)

High-bandwidth Digital Content Protection (HDCP) is a newer form of digital rights management (DRM). Intel created the original technology to make sure that digital content followed the guidelines set by the Digital Content Protection group.

HDMI can use HDCP to encrypt the signal if required by the source device. Content Scramble System (CSS), Content Protection for Recordable Media (CPRM) and Advanced Access Content System (AACS) require the use of HDCP on HDMI when playing back encrypted DVD Video, DVD Audio, HD DVD and Blu-ray Discs. The HDCP repeater bit controls the authentication and switching/distribution of an HDMI signal. According to HDCP Specification 1.2 (beginning with HDMI CTS 1.3a), any system that implements HDCP must do so in a fully compliant manner. HDCP testing that was previously only a requirement for optional tests such as the "Simplay HD" testing program is now part of the requirements for HDMI compliance. HDCP accommodates up to 127 connected devices with up to 7 levels, using a combination of sources, sinks and repeaters. A simple example of this is several HDMI devices connected to an HDMI AV receiver that is connected to an HDMI display. though a fair use and non-disclosure form must usually be signed with a registering agency before use.

Connectors

thumb|Connector types for HDMI|upright=1.8

alt=A close up image of the end three HDMI plugs: type D, type C and type A.|thumb|HDMI connector plugs (male): type D (Micro), type C (Mini), and type A

thumb|alt=An HDMI type A receptacle connector on a device with the words HDMI IN below it.|HDMI type A receptacle

There are five HDMI connector types. Type A/B are defined in the HDMI 1.0 specification, type C is defined in the HDMI 1.3 specification, and type D/E are defined in the HDMI 1.4 specification.

; Type A; Standard : The plug (male) connector outside dimensions are 13.9 mm × 4.45 mm, and the receptacle (female) connector inside dimensions are 14 mm × 4.55 mm. measuring only 5.83 mm × 2.20 mm

; Type E; Automotive : The Automotive Connection System has a locking tab to keep the cable from vibrating loose and a shell to help prevent moisture and dirt from corroding the pins.

The HDMI alternate mode lets a user connect the reversible USB-C connector with the HDMI source devices (mobile, tablet, laptop). This cable connects to video display/sink devices using any of the native HDMI connectors. This is an HDMI cable, in this case a USB-C to HDMI cable.

Cables

thumb|A standard HDMI cable

thumb|upright|HDMI pins in connector exposed

An HDMI cable is composed of four shielded twisted pairs, with a characteristic impedance of 100 Ω (±15%), plus seven separate conductors. HDMI cables with Ethernet differ in that three of the separate conductors instead form an additional shielded twisted pair (with the CEC/DDC ground as a shield). and certification is difficult to achieve for lengths beyond 13 m. HDMI 1.3 defines two cable categories: Category 1-certified cables, which have been tested at 74.25 MHz (which would include resolutions such as 720p60 and 1080i60), and Category 2-certified cables, which have been tested at 340 MHz (which would include resolutions such as 1080p60 and 4K30). Category 1 HDMI cables are marketed as "Standard" and Category 2 HDMI cables as "High Speed". Category 1 and 2 cables can either meet the required parameter specifications for inter-pair skew, far-end crosstalk, attenuation and differential impedance, or they can meet the required non-equalized/equalized eye diagram requirements.

HDMI cables are certified to guarantee a certain level of performance at an Authorized Testing Center (ATC). As of the HDMI 2.2 specification, the following certifications are defined for HDMI cables in consumer applications:

|+ HDMI cable certifications

! Certification name

! Guaranteed bit rate

! Description

| Standard HDMI Cable || rowspan="2" style="text-align:right; " | || rowspan="2" | Tested up to 74.25MHz TMDS (approximately at 60Hz or at 30Hz). The ARC and inline Ethernet features require the "with Ethernet" type.

| Standard HDMI Cable with Ethernet

| High Speed HDMI Cable || rowspan="2" style="text-align:right" | || rowspan="2" | Tested up to 340MHz TMDS (approximately at 144Hz or at 75Hz). The ARC and inline Ethernet features require the "with Ethernet" type.

| High Speed HDMI Cable with Ethernet

| Premium High Speed HDMI cable || rowspan="2" style="text-align:right" | || rowspan="2" | Tested up to 600MHz TMDS (approximately at 240Hz, at 144Hz, or at 60Hz). The ARC and inline Ethernet features require the "with Ethernet" type.

| Premium High Speed HDMI Cable with Ethernet

| Ultra High Speed HDMI cable || style="text-align:right" | || Tested at FRL 48Gbit/s (approximately at 144Hz with HDR).

| Ultra96 HDMI cable || style="text-align:right" | || Tested at FRL 96Gbit/s (approximately at 288Hz with HDR).

Separate certifications also exist for "automotive" Standard and High Speed HDMI cables, which use a different connector with a latching mechanism.

Extenders

Long cables can cause instability of HDCP and blinking on the screen due to the weakened DDC signal that HDCP requires. An extender can be used to address this instability. An HDMI extender is a single device (or pair of devices) powered with an external power source or from the 5VDC from the HDMI source.

Standard HDMI cables
Active HDMI cables use electronics within the cable to boost the signal and allow for HDMI cables of up to . There is a standard for AV over single-Ethernet-cable, HDBaseT, which is used by some extenders as the on-wire format. HDBaseT has a maximum reach of 100 meters.
HDMI extenders that are based on dual Category 5/Category 6 cable can extend HDMI to .

HDMI adopters

While earlier versions of HDMI specs are available to the public for download, only adopters have access to the latest standards (HDMI 1.4b/2.1). Only adopters have access to the compliance test specification (CTS) that is used for compliance and certification. Compliance testing is required before any HDMI product can be legally sold.

Adopters have IP rights under Adopter Agreement.
Adopters receive the right to use HDMI logos and trademarks on their products and marketing materials.
Adopters are listed on the HDMI website.
Products from adopters are listed and marketed in the official HDMI product finder database.
Adopters receive more exposure through combined marketing, such as the annual HDMI Developers Conference and technology seminars.

HDMI fee structure

There are two annual fee structures associated with being an HDMI adopter:

High-volume (more than 10,000 units) HDMI Adopter Agreement per year.
Low-volume (10,000 units or fewer) HDMI Adopter Agreement plus a flat per unit administration fee.

In 2009, HDMI Licensing banned the use of "version numbers" in labeling HDMI products. Instead, HDMI devices should explicitly declare which features and capabilities they support. For HDMI cables, a speed rating system was established since feature support is not dependent on the cable (apart from inline Ethernet and ARC); the cable only affects the maximum possible speed of the connection.

Version 1.1

HDMI 1.1 was released on May 20, 2004, and added support for DVD-Audio.

Version 1.2

HDMI 1.2 was released on August 8, 2005, and added the option of One Bit Audio, used on Super Audio CDs, at up to 8 channels. To make HDMI more suitable for use on PC devices, version 1.2 also removed the requirement that only explicitly supported formats be used. It added the ability for manufacturers to create vendor-specific formats, allowing any arbitrary resolution and refresh rate rather than being limited to a pre-defined list of supported formats. In addition, it added explicit support for several new formats including 720p at 100 and 120 Hz and relaxed the pixel format support requirements so that sources with only native RGB output (PC sources) would not be required to support output.

HDMI 1.2a was released on December 14, 2005 and fully specifies Consumer Electronic Control (CEC) features, command sets and CEC compliance tests. Like previous versions, it uses TMDS encoding, giving it a maximum video bandwidth of (sufficient for at 144Hz or at 75Hz). It added support for 10bpc, 12bpc, and 16bpc color depth (30, 36, and 48bit/px), called deep color. It also added support for the xvYCC color space, in addition to the ITU-R BT.601 and BT.709 color spaces supported by previous versions, and added the ability to carry metadata defining color gamut boundaries. It also optionally allows output of Dolby TrueHD and DTS-HD Master Audio streams for external decoding by AV receivers. It incorporates automatic audio syncing (audio video sync) capability.

HDMI 1.3a was released on November 10, 2006, and had cable and sink modifications for HDMI type C, source termination recommendations, and removed undershoot and maximum rise/fall time limits. It also changed CEC capacitance limits, and CEC commands for timer control were brought back in an altered form, with audio control commands added. It also added the optional ability to stream SACD in its bitstream DST format rather than uncompressed raw DSD.

Version 1.4

thumb|HDMI 1.4 with audio return channel

HDMI 1.4 was released on June 5, 2009, and first came to market after Q2 of 2009. Retaining the bandwidth of the previous version, HDMI 1.4 defined standardized timings to use for 40962160 at 24Hz, 38402160 at 24, 25, and 30Hz, and added explicit support for 19201080 at 120Hz with CTA-861 timings. It also added an HDMI Ethernet Channel (HEC) that accommodates a Ethernet connection between the two HDMI connected devices so they can share an Internet connection, introduced an audio return channel (ARC), 3D Over HDMI, a new Micro HDMI Connector, an expanded set of color spaces with the addition of sYCC601, Adobe RGB and Adobe YCC601, and an Automotive Connection System. HDMI 1.4 defined several stereoscopic 3D formats including field alternative (interlaced), frame packing (a full resolution top-bottom format), line alternative full, side-by-side half, side-by-side full, 2D + depth, and 2D + depth + graphics + graphics depth (WOWvx). HDMI 1.4 requires that 3D displays implement the frame packing 3D format at either 720p50 and 1080p24 or 720p60 and 1080p24. HDMI 1.4a has defined mandatory 3D formats for broadcast, game, and movie content. containing only minor clarifications to the 1.4a document. HDMI 1.4b is the last version of the standard that HDMI LA is responsible for. All later versions of the HDMI Specification are produced by the HDMI Forum, created on October 25, 2011.

Version 2.0

HDMI 2.0, referred to by some manufacturers as HDMI UHD, was released on September 4, 2013. HDMI 2.0 uses TMDS encoding for video transmission like previous versions, giving it a maximum video bandwidth of . This enables HDMI 2.0 to carry 4K video at 60 Hz with 24 bit/px color depth. Other features of HDMI 2.0 include support for the Rec. 2020 color space, up to 32 audio channels, up to 1536 kHz audio sample frequency, dual video streams to multiple users on the same screen, up to four audio streams, 4:2:0 chroma subsampling, 25 fps 3D formats, support for the 21:9 aspect ratio, dynamic synchronization of video and audio streams, the HE-AAC and DRA audio standards, improved 3D capability, and additional CEC functions.

HDMI 2.0a was released on April 8, 2015, and added support for High Dynamic Range (HDR) video with static metadata.

HDMI 2.0b was released March 2016. HDMI 2.0b initially supported the same HDR10 standard as HDMI 2.0a as specified in the CTA-861.3 specification.

Version 2.1

HDMI 2.1 was officially announced by the HDMI Forum on January4, 2017, and was released on November 28, 2017. It adds support for higher resolutions and higher refresh rates, including 4K 120Hz and 8K 60Hz. HDMI 2.1 also introduces a new HDMI cable category called Ultra High Speed (referred to as 48G during development), which certifies cables at the new higher speeds that these formats require. Ultra High Speed HDMI cables are backwards compatible with older HDMI devices, and older cables are compatible with new HDMI 2.1 devices, though the full bandwidth is only supported with the new cables.

Some systems may not be able to use HDMI 2.1 because the HDMI Forum is preventing its use in open source implementations (such as Linux open source drivers). Users of those systems may need to use DisplayPort instead to access high resolutions and speeds.

The following features were added to the HDMI 2.1 Specification:

Maximum supported format is 10K at 120Hz
Dynamic HDR for specifying HDR metadata on a scene-by-scene or even a frame-by-frame basis
Note: While HDMI 2.1 did standardize transport of dynamic HDR metadata over HDMI, in actuality it only formalized dynamic metadata interfaces already utilized by Dolby Vision and HDR10+ in HDMI 2.0, which is why neither Dolby Vision nor HDR10+ require HDMI 2.1 to function properly.
Display Stream Compression (DSC) 1.2 is used for video formats higher than 8K with 4:2:0 chroma subsampling
High Frame Rate (HFR) for 4K, 8K, and 10K, which adds support for refresh rates up to 120Hz
Enhanced Audio Return Channel (eARC) for object-based audio formats such as Dolby Atmos and DTS:X
Enhanced refresh rate and latency reduction features:
Variable Refresh Rate (VRR) reduces or eliminates lag, stutter and frame tearing for more fluid motion in games
Quick Media Switching (QMS) for movies and video eliminates the delay that can result in blank screens before content begins to be displayed
Quick Frame Transport (QFT) reduces latency by bursting individual pictures across the HDMI link as fast as possible when the link's hardware supports more bandwidth than the minimum amount needed for the resolution and frame rate of the content. With QFT, individual pictures arrive earlier and some hardware blocks can be fully powered off for longer periods of time between pictures to reduce heat generation and extend battery life.
Auto Low Latency Mode (ALLM)Allows the HDMI source device to direct the display to optimize either for low latency at the expense of image quality or for image quality at the expense of latency, presumably according to the content.

Video formats that require more bandwidth than (4K 60Hz 8bpc RGB), such as 4K 60Hz 10bpc (HDR), 4K 120Hz, and 8K 60Hz, may require the new "Ultra High Speed" or "Ultra High Speed with Ethernet" cables.

The bandwidth provided by HDMI 2.1 is enough for 8K resolution at approximately 50Hz, with 8bpc RGB or 4:4:4 color. To achieve even higher formats, HDMI 2.1 can use Display Stream Compression (DSC) with a compression ratio of up to . Using DSC, formats up to 8K () 120Hz or 10K () 100Hz at 8bpc RGB/4:4:4 are possible. Using with 4:2:2 or 4:2:0 chroma subsampling in combination with DSC can allow for even higher formats.

Version 2.2

HDMI 2.2 was announced on January 6, 2025, it was released on June 25, 2025. The maximum allowed bit rate is increased to and Latency Indication Protocol (LIP) support is added for improving audio and video synchronization.

Version comparison

Main specifications

{| class="wikitable sticky-header" style="font-size:92%"

! HDMI version

! style="min-width:80px" | 1.01.2a || style="min-width:80px" | 1.31.3a || style="min-width:80px" | 1.41.4b || style="min-width:80px" | 2.02.0b || style="min-width:80px" | 2.12.1b || style="min-width:80px" | 2.2

|- style="font-size:83%"

|style="font-size:120%"| Release date

| Jun 2025

| colspan="7" style="background:#EAECF0"| Signal specifications

|- align="right"

| align="left" | Max. transmission bit rate (Gbit/s) || 4.95 || 10.2 || 10.2 || 18.0 || 48.0 || 96.0

|- align="right"

| align="left" | Max. data rate (Gbit/s) || 3.96 || 8.16 || 8.16 || 14.4 || 42.0 || 84.0

|- align="right"

| align="left" | Max. TMDS character rate (MHz) || || || || For FRL transmission, the limits are calculated using the capacity computation algorithm provided by the HDMI Specification. All calculations assume uncompressed RGB video with CVT-RB v2 timing. Maximum limits may differ if compression (i.e. DSC) or 4:2:0 chroma subsampling are used.

Display manufacturers may also use non-standard blanking intervals (a Vendor-Specific Timing Format as defined in the HDMI Specification There is no officially defined correlation between features supported by a device and any claimed "version numbers", as version numbers refer to historical editions of the HDMI specification document, not to particular classes of HDMI devices. Manufacturers are forbidden from describing their devices using HDMI version numbers, and are required to identify support for features by listing explicit support for them, but the HDMI forum has received criticism for lack of enforcement of these policies.

Full HD Blu-ray Disc and HD DVD video (version 1.0)
Consumer Electronic Control (CEC) (version 1.0)
DVD-Audio (version 1.1)
Super Audio CD (DSD) (version 1.2)
Auto Lip-Sync Correction (version 1.3)
Dolby TrueHD / DTS-HD Master Audio bitstream capable (version 1.3)
Updated list of CEC commands (version 1.3a)

History

Specifications

Communication channels

HDMI Ethernet and Audio Return Channel

HDMI Ethernet Channel (HEC)<span class="anchor" id="HEC"></span><span class="anchor" id="HDMI Ethernet Channel"></span>

Compatibility with DVI

Content protection (HDCP)

Connectors

Cables

Extenders

HDMI adopters

HDMI fee structure

Version 1.1<span class="anchor" id="1.1"></span>

Version 1.2<span class="anchor" id="1.2"></span>

Version 1.4<span class="anchor" id="1.4"></span>

Version 2.0<span class="anchor" id="2.0"></span>

Version 2.1<span class="anchor" id="2.1"></span>

Version 2.2<span class="anchor" id="2.1"></span>

Version comparison

Main specifications