High-Definition Multimedia Interface (HDMI) is a

proprietary {{Short pages monitor Gbit/s as well. These changes increase the aggregate bandwidth from 18.0Gbit/s (3 × 6.0Gbit/s) to 48.0Gbit/s (4 × 12.0Gbit/s), a 2.66× improvement in bandwidth. In addition, the data is transmitted more efficiently by using a 16b/18b encoding scheme, which uses a larger percentage of the bandwidth for data rather than DC balancing compared to the TMDS scheme used by previous versions (88.% compared to 80%). This, in combination with the 2.66× bandwidth, raises the maximum data rate of HDMI 2.1 from 14.4Gbit/s to 42.Gbit/s. Subtracting overhead for FEC, the usable data rate is approximately 42.0Gbit/s, around 2.92× the data rate of HDMI 2.0. The 48Gbit/s 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 DisplayPort (DP) is a digital display interface developed by a consortium of PC and chip manufacturers and standardized by the Video Electronics Standards Association (VESA). It is primarily used to connect a video source to a display device su ...

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 comparison

The "version" of a connection depends on the versions of the HDMI ports on the source and sink devices, not on the HDMI cable. The different categories of HDMI cable only affect the bandwidth (maximum resolution / refresh rate) of the connection. Other features such as audio, 3D, chroma subsampling, or variable refresh rate depend only on the versions of the ports, and are not affected by what type of HDMI cable is used. The only exception to this is Ethernet-over-HDMI, which requires an "HDMI with Ethernet" cable. Products are not required to implement all features of a version to be considered compliant with that version, as most features are optional. For example, displays with HDMI 1.4 ports do not necessarily support the full 340 MHz TMDS clock allowed by HDMI 1.4; they are commonly limited to lower speeds such as 300 MHz (1080p 120 Hz) or even as low as 165 MHz (1080p 60 Hz) at the manufacturer's discretion, but are still considered HDMI 1.4-compliant. Likewise, features like 10 bpc (30 bit/px) color depth may also not be supported, even if the HDMI version allows it and the display supports it over other interfaces such as DisplayPort. Feature support will therefore vary from device to device, even within the same HDMI version.

Main specifications

Refresh frequency limits for common resolutions

The maximum limits for TMDS transmission are calculated using standard data rate calculations. 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) rather than CVT-RB v2 to achieve even higher frequencies when bandwidth is a constraint. The refresh frequencies in the below table do not represent the absolute maximum limit of each interface, but rather an estimate based on a modern standardized timing formula. The minimum blanking intervals (and therefore the exact maximum frequency that can be achieved) will depend on the display and how many secondary data packets it requires, and therefore will differ from model to model.

Refresh frequency limits for standard video

HDMI 1.0 and 1.1 are restricted to transmitting only certain video formats, defined in EIA/CEA-861-B and in the HDMI Specification itself. HDMI 1.2 and all later versions allow any arbitrary resolution and frame rate (within the bandwidth limit). Formats that are not supported by the HDMI Specification (i.e., no standardized timings defined) may be implemented as a vendor-specific format. Successive versions of the HDMI Specification continue to add support for additional formats (such as 4K resolutions), but the added support is to establish standardized timings to ensure interoperability between products, not to establish which formats are or aren't permitted. Video formats do not require explicit support from the HDMI Specification in order to be transmitted and displayed. Individual products may have heavier limitations than those listed below, since HDMI devices are not required to support the maximum bandwidth of the HDMI version that they implement. Therefore, it is not guaranteed that a display will support the refresh rates listed in this table, even if the display has the required HDMI version. Uncompressed 8bpc (24bit/px) color depth and RGB or 4:4:4 color format are assumed on this table except where noted.

Refresh frequency limits for HDR10 video

HDR10 requires 10bpc (30bit/px) color depth, which uses 25% more bandwidth than standard 8bpc video. Uncompressed 10bpc color depth and RGB or 4:4:4 color format are assumed on this table except where noted.

Feature support

The features defined in the HDMI Specification that an HDMI device may implement are listed below. For historical interest, the version of the HDMI Specification in which the feature was first added is also listed. All features of the HDMI Specification are optional; HDMI devices may implement any combination of these features. Although the "HDMI version numbers" are commonly misused as a way of indicating that a device supports certain features, this notation has no official meaning and is considered improper by HDMI Licensing. 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 HD DVD (short for High Definition Digital Versatile Disc) is an obsolete high-density optical disc format for storing data and playback of high-definition video. Supported principally by Toshiba, HD DVD was envisioned to be the successor to the ...

video (version 1.0) * Consumer Electronic Control (CEC) (version 1.0) *

DVD-Audio DVD-Audio (commonly abbreviated as DVD-A) is a digital format for delivering high-fidelity audio content on a DVD. DVD-Audio uses most of the storage on the disc for high-quality audio and is not intended to be a video delivery format. The st ...

(version 1.1) *

Super Audio CD Super Audio CD (SACD) is an optical disc format for audio storage introduced in 1999. It was developed jointly by Sony and Philips Electronics and intended to be the successor to the Compact Disc (CD) format. The SACD format allows multiple a ...

( DSD) (version 1.2) * Auto

Lip-Sync Lip sync or lip synch (pronounced , the same as the word ''sink'', short for lip synchronization) is a technical term for matching a speaking or singing person's lip movements with sung or spoken vocals. Audio for lip syncing is generated th ...

Correction (version 1.3) *

Dolby TrueHD Dolby TrueHD is a lossless, multi-channel audio codec developed by Dolby Laboratories for home video, used principally in Blu-ray Disc and compatible hardware. Dolby TrueHD, along with Dolby Digital Plus (E-AC-3) and Dolby AC-4, is one of the i ...

DTS-HD Master Audio DTS-HD Master Audio (DTS-HD MA; known as DTS++ before 2004) is a multi-channel, lossless audio codec developed by DTS as an extension of the lossy DTS Coherent Acoustics codec (DTS CA; usually itself referred to as just DTS). Rather than being ...

bitstream capable (version 1.3) * Updated list of CEC commands (version 1.3a) * 3D video (version 1.4) * Ethernet channel (100Mbit/s) (version 1.4) * Audio return channel (ARC) (version 1.4) * 4 audio streams (version 2.0) * Dual View (version 2.0) * Perceptual quantizer HDR EOTF (SMPTE ST 2084) (version 2.0a) *

Hybrid log–gamma The hybrid log–gamma (HLG) transfer function is a transfer function jointly developed by the BBC and NHK for high dynamic range (HDR) display. It's backward compatible with the transfer function of SDR (the gamma curve). It was approved as ARIB ...

(HLG) HDR EOTF (version 2.0a) * Static HDR metadata ( SMPTE ST 2086) (version 2.0a) * Dynamic HDR metadata ( SMPTE ST 2094) (version 2.0b) * Enhanced audio return channel (eARC) (version 2.1) * Variable Refresh Rate (VRR) (version 2.1) * Quick Media Switching (QMS) (version 2.1) * Quick Frame Transport (QFT) (version 2.1) * Auto Low Latency Mode (ALLM) (version 2.1) * Display Stream Compression (DSC) (version 2.1) * Source-Based Tone Mapping (SBTM) (version 2.1a)

Display Stream Compression

''Display Stream Compression'' (DSC) is a

VESA VESA (), formally known as Video Electronics Standards Association, is an American technical standards organization for computer display standards. The organization was incorporated in California in July 1989To retrieve the information, searc ...

-developed video compression algorithm designed to enable increased display resolutions and frame rates over existing physical interfaces, and make devices smaller and lighter, with longer battery life. It is a low-latency algorithm based on delta PCM coding and YCC-R color space. Although DSC is mathematically

lossy In information technology, lossy compression or irreversible compression is the class of data compression methods that uses inexact approximations and partial data discarding to represent the content. These techniques are used to reduce data size ...

, it meets the ISO/IEC 29170 standard for "visually lossless" compression, a form of compression in which "the user cannot tell the difference between a compressed and uncompressed image". ISO 29170 more specifically defines an algorithm as visually lossless "when all the observers fail to correctly identify the reference image more than 75% of the trials". However, the standard allows for images that "exhibit particularly strong artefacts" to be disregarded or excluded from testing, such as engineered test images. Research of DSC using the ISO/IEC 29170 interleaved protocol, in which an uncompressed reference image is presented side by side with a rapidly alternating sequence of the compressed test image and uncompressed reference image, and performed with various types of images (such as people, natural and man-made scenery, text, and known challenging imagery) shows that in most images DSC satisfies the standard's criterion for visually lossless performance, although in some trials participants were able to detect the presence of compression on certain images. DSC compression works on a horizontal line of pixels encoded using groups of three consecutive pixels for native 4:4:4 and simple 4:2:2 formats, or six pixels (three compressed containers) for native 4:2:2 and 4:2:0 formats. If RGB encoding is used, it is first converted to reversible YCC. Simple conversion from 4:2:2 to 4:4:4 can add missing chroma samples by interpolating neighboring pixels. Each luma component is coded separately using three independent substreams (four substreams in native 4:2:2 mode). Prediction step is performed using one of the three modes: modified median adaptive coding (MMAP) algorithm similar to the one used by

JPEG-LS Lossless JPEG is a 1993 addition to JPEG standard by the Joint Photographic Experts Group to enable lossless compression. However, the term may also be used to refer to all lossless compression schemes developed by the group, including JPEG 2000 an ...

, block prediction (optional for decoders due to high computational complexity, negotiated at DSC handshake), and midpoint prediction. Bit rate control algorithm tracks color flatness and buffer fullness to adjust the quantization bit depth for a pixel group in a way that minimizes compression artifacts while staying within the bitrate limits. Repeating recent pixels can be stored in 32-entry Indexed Color History (ICH) buffer, which can be referenced directly by each group in a slice; this improves compression quality of computer-generated images. Alternatively, prediction residuals are computed and encoded with

entropy coding In information theory, an entropy coding (or entropy encoding) is any lossless data compression method that attempts to approach the lower bound declared by Shannon's source coding theorem, which states that any lossless data compression method ...

algorithm based on delta size unit-variable length coding (DSU-VLC). Encoded pixel groups are then combined into slices of various height and width; common combinations include 100% or 25% picture width, and 8-, 32-, or 108-line height.

Applications

Blu-ray Disc and HD DVD players

Blu-ray Disc and

, introduced in 2006, offer high-fidelity audio features that require HDMI for best results. HDMI 1.3 can transport

Dolby Digital Plus Dolby Digital Plus, also known as Enhanced AC-3 (and commonly abbreviated as DDP, DD+, E-AC-3 or EC-3) is a digital audio compression scheme developed by Dolby Labs for transport and storage of multi-channel digital audio. It is a successor to D ...

, and

bitstreams in compressed form. This capability allows for an

AV receiver An audio/video receiver (AVR) is a consumer electronics component used in a home theater. Its purpose is to receive audio and video signals from a number of sources, and to process them and provide power amplifiers to drive loudspeakers and ro ...

with the necessary decoder to decode the compressed audio stream. The Blu-ray specification does not include video encoded with either deep color or xvYCC; thus, HDMI 1.0 can transfer Blu-ray discs at full video quality. The HDMI 1.4 specification (released in 2009) added support for 3D video and is used by all Blu-ray 3D compatible players. The Blu-ray Disc Association (BDA) spokespersons have stated (Sept. 2014 at IFA show in Berlin, Germany) that the Blu-ray, Ultra HD players, and 4K discs are expected to be available starting in the second half to 2015. It is anticipated that such Blu-ray UHD players will be required to include a HDMI 2.0 output that supports HDCP 2.2. Blu-ray permits secondary audio decoding, whereby the disc content can tell the player to mix multiple audio sources together before final output. Some Blu-ray and HD DVD players can decode all of the audio

codec A codec is a device or computer program that encodes or decodes a data stream or signal. ''Codec'' is a portmanteau of coder/decoder. In electronic communications, an endec is a device that acts as both an encoder and a decoder on a signal or ...

s internally and can output LPCM audio over HDMI. Multichannel LPCM can be transported over an HDMI connection, and as long as the

implements multichannel LPCM audio over HDMI and implements

HDCP High-bandwidth Digital Content Protection (HDCP) is a form of digital copy protection developed by Intel Corporation to prevent copying of digital audio and video content as it travels across connections. Types of connections include DisplayPort ...

, the audio reproduction is equal in resolution to HDMI 1.3 bitstream output. Some low-cost AV receivers, such as the Onkyo TX-SR506, do not allow audio processing over HDMI and are labelled as "HDMI pass through" devices. Virtually all modern AV Receivers now offer HDMI 1.4 inputs and outputs with processing for all of the audio formats offered by Blu-ray Discs and other HD video sources. During 2014 several manufacturers introduced premium AV Receivers that include one, or multiple, HDMI 2.0 inputs along with a HDMI 2.0 output(s). However, not until 2015 did most major manufacturers of AV receivers also support HDCP 2.2 as needed to support certain high quality UHD video sources, such as Blu-ray UHD players.

Digital cameras and camcorders

Most consumer camcorders, as well as many digital cameras, are equipped with a mini-HDMI connector (type C connector). Some cameras also have 4K capability, although cameras capable of

HD video High-definition video (HD video) is video of higher resolution and quality than standard-definition. While there is no standardized meaning for ''high-definition'', generally any video image with considerably more than 480 vertical scan lines (N ...

often include an HDMI interface for playback or even

live preview Live preview is a feature that allows a digital camera's display screen to be used as a viewfinder. This provides a means of previewing framing and other exposure before taking the photograph. In most such cameras, the preview is generated by m ...

, the

image processor An image processor, also known as an image processing engine, image processing unit (IPU), or image signal processor (ISP), is a type of media processor or specialized digital signal processor (DSP) used for image processing, in digital cameras ...

and the

video processor In electronics engineering, video processing is a particular case of signal processing, in particular image processing, which often employs video filters and where the input and output signals are video files or video streams. Video processing te ...

of cameras usable for uncompressed video must be able to deliver the full

image resolution Image resolution is the detail an image holds. The term applies to digital images, film images, and other types of images. "Higher resolution" means more image detail. Image resolution can be measured in various ways. Resolution quantifies how ...

at the specified frame rate in real time without any missing frames causing jitter. Therefore, usable uncompressed video out of HDMI is often called "clean HDMI".

Personal computers

Personal computer A personal computer (PC) is a multi-purpose microcomputer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be operated directly by an end user, rather than by a computer expert or tec ...

(PCs) with a

DVI Digital Visual Interface (DVI) is a video display interface developed by the Digital Display Working Group (DDWG). The digital interface is used to connect a video source, such as a video display controller, to a display device, such as a comp ...

interface are capable of video output to an HDMI-enabled monitor. Some PCs include an HDMI interface and may also be capable of HDMI audio output, depending on specific hardware. For example, Intel's motherboard chipsets since the 945G and NVIDIA's

GeForce GeForce is a brand of graphics processing units (GPUs) designed by Nvidia. As of the GeForce 40 series, there have been eighteen iterations of the design. The first GeForce products were discrete GPUs designed for add-on graphics boards, inte ...

8200/8300 motherboard chipsets are capable of 8-channel LPCM output over HDMI. Eight-channel LPCM audio output over HDMI with a video card was first seen with the ATI Radeon HD 4850, which was released in June 2008 and is implemented by other video cards in the ATI Radeon HD 4000 series.

Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, w ...

can drive 8-channel LPCM audio over HDMI if the video card has the necessary hardware and implements the

Advanced Linux Sound Architecture Advanced Linux Sound Architecture (ALSA) is a software framework and part of the Linux kernel that provides an application programming interface (API) for sound card device drivers. Some of the goals of the ALSA project at its inception w ...

(ALSA). The ATI Radeon HD 4000 series implements ALSA. Cyberlink announced in June 2008 that they would update their PowerDVD playback software to allow 192 kHz/24-bit Blu-ray Disc audio decoding in Q3-Q4 of 2008. Corel's WinDVD 9 Plus currently has 96 kHz/24-bit Blu-ray Disc audio decoding. Even with an HDMI output, a computer may not be able to produce signals that implement

, Microsoft's Protected Video Path, or Microsoft's Protected Audio Path. Several early graphic cards were labelled as "HDCP-enabled" but did not have the hardware needed for HDCP; this included some graphic cards based on the ATI X1600 chipset and certain models of the NVIDIA Geforce 7900 series. The first computer monitors that could process HDCP were released in 2005; by February 2006 a dozen different models had been released. The Protected Video Path was enabled in graphic cards that had HDCP capability, since it was required for output of Blu-ray Disc and HD DVD video. In comparison, the Protected Audio Path was required only if a lossless audio bitstream (such as Dolby TrueHD or DTS-HD MA) was output. Uncompressed LPCM audio, however, does not require a Protected Audio Path, and software programs such as PowerDVD and WinDVD can decode Dolby TrueHD and DTS-HD MA and output it as LPCM. A limitation is that if the computer does not implement a Protected Audio Path, the audio must be downsampled to 16-bit 48 kHz but can still output at up to 8 channels. No graphic cards were released in 2008 that implemented the Protected Audio Path. The Asus Xonar HDAV1.3 became the first HDMI sound card that implemented the Protected Audio Path and could both bitstream and decode lossless audio (Dolby TrueHD and DTS-HD MA), although bitstreaming is only available if using the ArcSoft TotalMedia Theatre software. It has an HDMI 1.3 input/output, and Asus says that it can work with most video cards on the market. In September 2009,

AMD Advanced Micro Devices, Inc. (AMD) is an American multinational semiconductor company based in Santa Clara, California, that develops computer processors and related technologies for business and consumer markets. While it initially manufactur ...

announced the ATI Radeon HD 5000 series video cards, which have HDMI 1.3 output (deep color, xvYCC wide gamut capability and high bit rate audio), 8-channel LPCM over HDMI, and an integrated HD audio controller with a Protected Audio Path that allows bitstream output over HDMI for AAC, Dolby AC-3, Dolby TrueHD and DTS-HD Master Audio formats. The ATI Radeon HD 5870 released in September 2009 is the first video card that allows bitstream output over HDMI for Dolby TrueHD and DTS-HD Master Audio. The AMD

Radeon HD 6000 Series The Northern Islands series is a family of GPUs developed by Advanced Micro Devices (AMD) forming part of its Radeon-brand, based on the 40 nm process. Some models are based on TeraScale 2 (VLIW5), some on the new TeraScale 3 (VLIW4) intr ...

implements HDMI 1.4a. The AMD

Radeon HD 7000 Series The Radeon HD 7000 series, codenamed "Southern Islands", is a family of GPUs developed by AMD, and manufactured on TSMC's 28 nm process. The primary competitor of Southern Islands, Nvidia's GeForce 600 Series (also manufactured at TSMC), ...

implements HDMI 1.4b. In December 2010, it was announced that several computer vendors and display makers including

Intel Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California. It is the world's largest semiconductor chip manufacturer by revenue, and is one of the developers of the x86 seri ...

, AMD, Dell, Lenovo,

Samsung The Samsung Group (or simply Samsung) ( ko, 삼성 ) is a South Korean multinational manufacturing conglomerate headquartered in Samsung Town, Seoul, South Korea. It comprises numerous affiliated businesses, most of them united under the ...

, and LG would stop using

LVDS Low-voltage differential signaling (LVDS), also known as TIA/EIA-644, is a technical standard that specifies electrical characteristics of a differential, serial signaling standard. LVDS operates at low power and can run at very high speeds ...

(actually,

FPD-Link Flat Panel Display Link, more commonly referred to as FPD-Link, is the original high-speed digital video interface created in 1996 by National Semiconductor (now within Texas Instruments). It is a free and open standard for connecting the output ...

) from 2013 and legacy DVI and

VGA Video Graphics Array (VGA) is a video display controller and accompanying de facto graphics standard, first introduced with the IBM PS/2 line of computers in 1987, which became ubiquitous in the PC industry within three years. The term can no ...

connectors from 2015, replacing them with

DisplayPort DisplayPort (DP) is a digital display interface developed by a consortium of PC and chip manufacturers and standardized by the Video Electronics Standards Association (VESA). It is primarily used to connect a video source to a display device su ...

and HDMI. On August 27, 2012, Asus announced a new monitor that produces its native resolution of 2560×1440 via HDMI 1.4. On September 18, 2014, Nvidia launched GeForce GTX 980 and GTX 970 (with GM204 chip) with HDMI 2.0 support. On January 22, 2015, GeForce GTX 960 (with GM206 chip) launched with HDMI 2.0 support. On March 17, 2015, GeForce GTX TITAN X (GM200) launched with HDMI 2.0 support. On June 1, 2015, GeForce GTX 980 Ti (with GM200 chip) launched with HDMI 2.0 support. On August 20, 2015, GeForce GTX 950 (with GM206 chip) launched with HDMI 2.0 support. On May 6, 2016, Nvidia launched the GeForce GTX 1080 (GP104 GPU) with HDMI 2.0b support. On September 1, 2020, Nvidia launched the GeForce RTX 30 series, the world's first discrete graphics cards with support for the full 48Gbit/s bandwidth with Display Stream Compression 1.2 of HDMI 2.1.

Gaming consoles

Beginning with the

seventh generation of video game consoles The seventh generation of home video game consoles began on November 22, 2005, with the release of Microsoft's Xbox 360 home console. This was followed by the release of Sony Computer Entertainment's PlayStation 3 on November 17, 2006, and Nint ...

, most consoles support HDMI. Video game consoles that support HDMI include the

Xbox 360 The Xbox 360 is a home video game console developed by Microsoft. As the successor to the original Xbox, it is the second console in the Xbox series. It competed with Sony's PlayStation 3 and Nintendo's Wii as part of the seventh generati ...

(1.2a),

Xbox One The Xbox One is a home video game console developed by Microsoft. Announced in May 2013, it is the successor to Xbox 360 and the third base console in the Xbox series of video game consoles. It was first released in North America, parts of ...

(1.4b),

Xbox One S The Xbox One is a home video game console developed by Microsoft. Announced in May 2013, it is the successor to Xbox 360 and the third base console in the Xbox series of video game consoles. It was first released in North America, parts of ...

(2.0a),

Xbox One X The Xbox One is a home video game console developed by Microsoft. Announced in May 2013, it is the successor to Xbox 360 and the third base console in the Xbox series of video game consoles. It was first released in North America, parts o ...

(2.0b),

PlayStation 3 The PlayStation 3 (PS3) is a home video game console developed by Sony Computer Entertainment. The successor to the PlayStation 2, it is part of the PlayStation brand of consoles. It was first released on November 11, 2006, in Japan, November ...

(1.3a), PlayStation 4 (1.4b),

PlayStation 4 Pro The PlayStation 4 (PS4) is a home video game console developed by Sony Interactive Entertainment. Announced as the successor to the PlayStation 3 in February 2013, it was launched on November 15, 2013, in North America, November 29, 2013 in E ...

(2.0a),

Wii U The Wii U ( ) is a home video game console developed by Nintendo as the successor to the Wii. Released in late 2012, it is the first eighth-generation video game console and competed with Microsoft's Xbox One and Sony's PlayStation 4. Th ...

(1.4a), Nintendo Switch (1.4b), Nintendo Switch (OLED model) (2.0a),

Xbox Series X and Series S The Xbox Series X/S are home video game consoles developed by Microsoft. They were both released on November 10, 2020, as the fourth generation Xbox, succeeding the Xbox One. Along with Sony's PlayStation 5, also released in November 2020, ...

(2.1), and PlayStation 5 (2.1).

Tablet computers

Some

tablet computer A tablet computer, commonly shortened to tablet, is a mobile device, typically with a mobile operating system and touchscreen display processing circuitry, and a rechargeable battery in a single, thin and flat package. Tablets, being com ...

s implement HDMI using Micro-HDMI (Type D) port , while others like the

Eee Pad The Asus Eee Pad Transformer TF101 is a 2-in-1 detachable tablet developed by Asus that runs the Android operating system. It is the first tablet in the Asus Transformer Pad series. The Eee Pad Transformer features a display, an Nvidia Tegr ...

Transformer implement the standard using mini-HDMI (type C) ports. All

iPad The iPad is a brand of iOS and iPadOS-based tablet computers that are developed by Apple Inc. The iPad was conceived before the related iPhone but the iPhone was developed and released first. Speculation about the development, operating ...

models have a special A/V adapter that converts Apple's Lightning (connector) to a standard HDMI (Type A) port. Samsung has a similar proprietary thirty-pin port for their

Galaxy Tab 10.1 The Samsung Galaxy Tab 10.1 is an Android (operating system), Android-based tablet computer designed and manufactured by Samsung, introduced in 2011. It is part of the Samsung Galaxy Tab series, and features a display and a 1 GHz dual-cor ...

that could adapt to HDMI as well as USB drives. The Dell Streak 5 smartphone/tablet hybrid is capable of outputting over HDMI. While the Streak uses a

PDMI PDMI (Portable Digital Media Interface) is an interconnection standard for portable media players. It has been developed by CEA (Consumer Electronics Association) as ANSI/CEA-2017-A standard ''Common Interconnection for Portable Media Players'' ...

port, a separate cradle adds HDMI compatibility. Some tablets running

Android OS Android is a mobile operating system based on a modified version of the Linux kernel and other open-source software, designed primarily for touchscreen mobile devices such as smartphones and tablets. Android is developed by a consortium of deve ...

provide HDMI output using a mini-HDMI (type C) port. Most new laptops and desktops now have built in HDMI as well.

Mobile phones

Many mobile phones can produce an output of HDMI video via a micro-HDMI connector,

SlimPort DisplayPort (DP) is a digital display interface developed by a consortium of PC and chip manufacturers and standardized by the Video Electronics Standards Association (VESA). It is primarily used to connect a video source to a display device su ...

, MHL or other adapter.

Legacy compatibility

HDMI can only be used with older analog-only devices (using connections such as

SCART SCART (also known as or , especially in France, 21-pin EuroSCART in marketing by Sharp in Asia, Euroconector in Spain, EuroAV or EXT, or EIA Multiport in the United States, as an EIA interface) is a French-originated standard and associated 2 ...

, RCA, etc.) by means of a

digital-to-analog converter In electronics, a digital-to-analog converter (DAC, D/A, D2A, or D-to-A) is a system that converts a digital signal into an analog signal. An analog-to-digital converter (ADC) performs the reverse function. There are several DAC archit ...

, as the interface does not carry any analog signals (unlike DVI, where devices with DVI-I ports accept or provide either digital or analog signals). Cables are available that contain the necessary electronics, but it is important to distinguish these ''active'' converter cables from ''passive'' HDMI to VGA cables (which are typically cheaper as they don't include any electronics). The passive cables are ''only'' useful if you have a device that is generating or expecting HDMI signals on a VGA connector, or VGA signals on an HDMI connector; this is a non-standard feature, not implemented by most devices.

HDMI Alternate Mode for USB Type-C

The HDMI Alternate Mode for

USB-C USB-C (properly known as USB Type-C) is a 24-pin USB connector system with a rotationally symmetrical connector. The designation C refers only to the connector's physical configuration or form factor and should not be confused with the conn ...

allows HDMI-enabled sources with a USB-C connector to directly connect to standard HDMI display devices, without requiring an adapter. The standard was released in September 2016, and supports all HDMI 1.4b features such as video resolutions up to

Ultra HD Ultra-high-definition television (also known as Ultra HD television, Ultra HD, UHDTV, UHD and Super Hi-Vision) today includes 4K UHD and 8K UHD, which are two digital video formats with an aspect ratio of 16:9. These were first proposed b ...

30 Hz and CEC. Previously, the similar

Alternate Mode could be used to connect to HDMI displays from USB Type-C sources, but where in that case, active adapters were required to convert from DisplayPort to HDMI, HDMI Alternate Mode connects to the display natively. The Alternate Mode reconfigures the four SuperSpeed differential pairs present in USB-C to carry the three HDMI

TMDS Transition-minimized differential signaling (TMDS), a technology for transmitting high-speed serial data, is used by the DVI and HDMI video interfaces, as well as by other digital communication interfaces. The transmitter incorporates an advan ...

channels and the clock signal. The two Sideband Use pins (SBU1 and SBU2) are used to carry the HDMI Ethernet and Audio Return Channel and the Hot Plug Detect functionality (HEAC+/Utility pin and HEAC−/HPD pin). As there are not enough reconfigurable pins remaining in USB-C to accommodate the DDC clock (SCL), DDC data (SDA), and CEC these three signals are bridged between the HDMI source and sink via the USB Power Delivery 2.0 (USB-PD) protocol, and are carried over the USB-C Configuration Channel (CC) wire. This is possible because the cable is electronically marked (i.e., it contains a USB-PD node) that serves to tunnel the DDC and CEC from the source over the Configuration Channel to the node in the cable, these USB-PD messages are received and relayed to the HDMI sink as regenerated DDC (SCL and SDA signals), or CEC signals.

Relationship with DisplayPort

The

audio/video interface was introduced in May 2006. In recent years, DisplayPort connectors have become a common feature of premium products—displays, desktop computers, and video cards; most of the companies producing DisplayPort equipment are in the computer sector. The DisplayPort website states that DisplayPort is expected to complement HDMI, but 100% of HD and UHD TVs had HDMI connectivity. DisplayPort supported some advanced features which are useful for multimedia content creators and gamers (e.g. 5K, Adaptive-Sync), which was the reason most GPUs have DisplayPort. These features were added to the official HDMI specification slightly later, but with the introduction of HDMI 2.1, these gaps are already leveled off (with e.g. VRR /

Variable Refresh Rate Variable refresh rate (VRR) refers to a dynamic display that can continuously and seamlessly change its refresh rate without user input. A display supporting a variable refresh rate usually supports a specific ''range'' of refresh rates (e.g. 30 ...

). DisplayPort uses a self-clocking, micro-packet-based protocol that allows for a variable number of differential

lanes as well as flexible allocation of bandwidth between audio and video, and allows encapsulating multi-channel compressed audio formats in the audio stream. DisplayPort 1.2 supports multiple audio/video streams, variable refresh rate (

FreeSync FreeSync is an adaptive synchronization technology for LCD and OLED displays that support a variable refresh rate aimed at avoiding tearing and reducing stuttering caused by misalignment between the screen's refresh rate and the content's fr ...

), and Dual-mode LVDS/TMDS transmitters compatible with HDMI 1.2 or 1.4. Revision 1.3 increases overall transmission bandwidth to 32.4Gbit/s with the new HBR3 mode featuring 8.1Gbit/s per lane; it requires Dual-mode with mandatory HDMI 2.0 compatibility and

2.2. Revision 1.4 adds Display Stream Compression (DSC), support for the

BT.2020 ITU-R Recommendation BT.2020, more commonly known by the abbreviations Rec. 2020 or BT.2020, defines various aspects of ultra-high-definition television (UHDTV) with standard dynamic range (SDR) and wide color gamut (WCG), including picture ...

color space, and

HDR10 HDR10 Media Profile, more commonly known as HDR10, is an open high-dynamic-range video (HDR) standard announced on 27 August 2015 by the Consumer Technology Association. It is the most widespread of the HDR formats. HDR10 is not backward compat ...

extensions from CTA-861.3, including static and dynamic metadata. The DisplayPort connector is compatible with HDMI and can transmit single-link

and HDMI 1.2/1.4/2.0 signals using attached passive adapters or adapter cables. The source device includes a dual-mode transmitter that supports both LVDS signals for DisplayPort and TMDS signals for DVI/HDMI. The same external connector is used for both protocols when a DVI/HDMI passive adapter is attached, the transmitter circuit switches to TMDS mode. DisplayPort Dual-mode ports and cables/adapters are typically marked with the DisplayPort++ logo.

Thunderbolt A thunderbolt or lightning bolt is a symbolic representation of lightning when accompanied by a loud thunderclap. In Indo-European mythology, the thunderbolt was identified with the 'Sky Father'; this association is also found in later Hel ...

ports with mDP connector also supports Dual-mode passive HDMI adapters/cables. Conversion to dual-link DVI and

component video Component video is an analog video signal that has been split into two or more component channels. In popular use, it refers to a type of component analog video (CAV) information that is transmitted or stored as three separate signals. Compo ...

(VGA/YPbPr) requires active powered adapters. The USB 3.1 Type-C connector is an emerging standard that replaces legacy video connectors such as mDP, Thunderbolt, HDMI, and VGA in mobile devices. USB-C connectors can transmit DisplayPort video to docks and displays using standard USB Type-C cables or Type-C to DisplayPort cables and adapters; USB-C also supports HDMI adapters that actively convert from DisplayPort to HDMI 1.4 or 2.0. DisplayPort Alternate Mode for USB Type-C specification was published in 2015. USB Type-C chipsets are not required to include Dual-mode transmitters and only support DisplayPort LVDS protocol, so passive DP-HDMI adapters do not work with Type-C sources. DisplayPort has a royalty rate of US$0.20 per unit (from patents licensed by

MPEG LA MPEG LA is an American company based in Denver, Colorado that licenses patent pools covering essential patents required for use of the MPEG-2, MPEG-4, IEEE 1394, VC-1, ATSC, MVC, MPEG-2 Systems, AVC/H.264 and HEVC standards. History MPEG LA ...

), while HDMI has an annual fee of US$10,000 and a per unit royalty rate of between $0.04 and $0.15. HDMI has a few advantages over DisplayPort, such as ability to carry Consumer Electronics Control (CEC) signals, and electrical compatibility with DVI (though practically limited to single-link DVI rates). Also, HDMI can sustain full bandwidth for up to 10 meters of cable length and there are certification programs to ensure this. VESA states that DisplayPort is specified and tested to run 15 metres without the need for a booster station, though Dell advises that problems can occur with DisplayPort cables longer than 1.8 metres. However,

active cable Active cables are copper cables for data transmission that use an electronic circuit to boost the performance of the cable. Without an electronic circuit, a cable is considered a passive cable. Passive cables are liable to degrade the data they ca ...

solutions and

fiber optic cable A fiber-optic cable, also known as an optical-fiber cable, is an assembly similar to an electrical cable, but containing one or more optical fibers that are used to carry light. The optical fiber elements are typically individually coated with ...

extender solutions can be used to extend effective DisplayPort distances.

Relationship with MHL

Mobile High-Definition Link (MHL) is an adaptation of HDMI intended to connect mobile devices such as smartphones and tablets to high-definition televisions (HDTVs) and displays. Unlike

, which is compatible with HDMI using only passive cables and adapters, MHL requires that the HDMI socket be MHL-enabled, otherwise an active adapter (or dongle) is required to convert the signal to HDMI. MHL is developed by a consortium of five consumer electronics manufacturers, several of which are also behind HDMI. MHL pares down the three TMDS channels in a standard HDMI connection to a single one running over any connector that provides at least five pins. This lets existing connectors in mobile devices such as

micro-USB The initial versions of the USB standard specified connectors that were easy to use and that would have acceptable life spans; revisions of the standard added smaller connectors useful for compact portable devices. Higher-speed development of ...

be used, avoiding the need for additional dedicated video output sockets. The USB port switches to MHL mode when it detects a compatible device is connected. In addition to the features in common with HDMI (such as

encrypted uncompressed high-definition video and eight-channel

surround sound Surround sound is a technique for enriching the fidelity and depth of sound reproduction by using multiple audio channels from speakers that surround the listener (surround channels). Its first application was in movie theaters. Prior to s ...

), MHL also adds the provision of power charging for the mobile device while in use, and also enables the TV remote to control it. Although support for these additional features requires connection to an MHL-enabled HDMI port, power charging can also be provided when using active MHL to HDMI adapters (connected to standard HDMI ports), provided there is a separate power connection to the adapter. Like HDMI, MHL defines a

Alternate Mode to support the MHL standard over USB-C connections. Version 1.0 supported 720p/1080i 60 Hz (RGB/4:4:4 pixel encoding) with a bandwidth of 2.25 Gbit/s. Versions 1.3 and 2.0 added support for

1080p 1080p (1920×1080 progressively displayed pixels; also known as Full HD or FHD, and BT.709) is a set of HDTV high-definition video modes characterized by 1,920 pixels displayed across the screen horizontally and 1,080 pixels down the screen ve ...

60 Hz ( 4:2:2) with a bandwidth of 3 Gbit/s in PackedPixel mode. Version 3.0 increased the bandwidth to 6 Gbit/s to support

(3840 × 2160) 30 Hz video, and also changed from being frame-based, like HDMI, to packet-based. The fourth version, superMHL, increased bandwidth by operating over multiple TMDS differential pairs (up to a total of six) allowing a maximum of 36 Gbit/s. The six lanes are supported over a reversible 32-pin superMHL connector, while four lanes are supported over

Alternate Mode (only a single lane is supported over micro-USB/HDMI).

(DSC) is used to allow up to 8K Ultra HD (7680 × 4320) 120 Hz HDR video, and to support Ultra HD 60 Hz video over a single lane.

References

External links

HDMI Licensing, LLC.

Dolby Podcast Episode 60 – March 26, 2009
Part one of a two-part discussion with Steve Venuti, President, and Jeff Park, Technology Evangelist, of

HDMI Licensing HDMI Licensing, LLC was founded by Hitachi, Panasonic, Philips, Silicon Image, Sony, Thomson (RCA) and Toshiba; it is their licensing vehicle for the HDMI High-Definition Multimedia Interface (HDMI) is a proprietary audio/video interface ...

.
Dolby Podcast Episode 62 – April 23, 2009
Part two of a two-part discussion with Steve Venuti, President, and Jeff Park, Technology Evangelist, of

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