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What is HDMI? Everything You Need to Know

What is HDMI
Written by prodigitalweb

What is HDMI? HDMI stands for High-Definition Multimedia Interface. It is proprietary hardware which means a patent controls it. A digital interface transmits uncompressed video signals and compressed and uncompressed audio signals in a single cable between HDMI compliant Source and Sink. In other words, it is a standard for the digital replacement for the old analog video standard. It complies with the EIA/CEA-861 standards.

EIA (Electronic Industries Alliance) is an American industry standard for electronics manufacturers in the USA. These kinds of industry standards aim to ensure gadgets of different manufacturers are compatible and interchangeable. For example, EIA/CEA-861 standards stipulate some standards for sending uncompressed video in the waveform. And audio, auxiliary data, and other Metadata comply with VESA EDID.

Hitachi founded it. Panasonic, Philips, Sony, Thomson, Toshiba, and RCA and supported by Universal Warner, Disney, and Fox. They first Employed HDCP protocol to ensure digital copy protection.

What are HDMI Versions and Their Specification:

2.1 Specification:

HDMI 2.1 specification is the recent update of Specification. It supports higher video resolutions with higher refresh rates like 8K @ 60 Hz and 4K @ 120K. Besides, it can support solutions up to 10K and dynamic HDR formats also. The bandwidth capability increased to the maximum of 48GbPs. A special Ultra high-speed HDMI cable is needed to support a bandwidth of 48Gbps. It is backward compatible with the old version as and when required.

Therefore you can use it with the existing setup of High-Definition Multimedia Interface gadgets. Moreover, it has extremely low electromagnetic interference. Therefore data transfer will not be affected by the interference of the wireless devices nearby. 2.1 Ultra High-Speed HDMI Cable is a category-3 cable. Category-3  exceeds the requirements of the latest international EMI standards to reduce interference with wireless services such as Wi-Fi significantly. Ultra High-Speed cables support all 2.0 and 1.4b features as well.

2.1 specifications include:

  • Supports Higher Video Resolutions
  • Supports Dynamic HDR
  • Needs Ultra High-Speed Cable
  • Most advanced Enhanced Audio Return Channel (eARC) replaces previous Audio Return Channel (ARC)
  • Auto Low Latency Mode Feature enables the ideal latency setting to be set automatically, allowing for smooth, lag-free, and uninterrupted gaming.
  • Quick Media Switching (QMS) eliminates the delay resulting in a blank screen before content displayed while watching the video.
  • QFT (Quick Frame Transport) feature reduces latency and Game Lagging. In addition, it offers real-time interactive virtual reality.
  • 1 specifications support the color spaces like BT.2020 with 10, 12, and 16 bits per color component
  • It supports Fixed Rate Link signaling technology.
  • 1 specification supports VESA DSC 1.2a link compression technology
  • It supports the following resolutions and frame rates 4K50/60, 4K100/120, 5K50/60, 5K100/120, 8K50/60, 8K100/120, 10K50/60, and 10K100/120
  • It supports various static and dynamic HDR solutions

2.0b Specification:

It was released in the year 2016 March. And, it is backward compatible.

It does not require any need for new cables and connectors. Initially, it supported all the features of 2.0a standard of HDR 10 format and static Metadata.

Further, in December 2016   provided additional support for HDR video transport as that of CTA-861-G specification. The Metadata signaling includes hybrid Log-Gamma. The broadcasters are using limited bandwidth.

In 2.0b HLG, it combined with HDR and SDR in the same TV signal. Thereby it saves broadband for more TV channels.

Note: Most TVs do not support HLG; hence the consumer faced some problems.

2.0a Specification:

2.0a was released in the first quarter of the year 2015. It added support to High Dynamic Range Video (HDR) with static Metadata. It supports all specifications specified in the CTA-861.3 Specification.  Its prime objective was to enhance the picture quality. And simultaneously enable minute details of both bright and dark parts of the image.

2.0 Specifications:

2.0 released on 2013, September 4. It is backward compatible with previous rolled-out versions of the Specification. In addition, it increases the bandwidth to a maximum of 18Gbit/seconds.

It uses TMDS encoding for video transmission with a maximum bandwidth of 14.4Gbit/ Seconds. It carries a 4K video at 60Hz with 24bit/px color depth. Besides, it supports Rec. 2020 color space and up to 32 audio channels with a sampling frequency of 1536 kHz.

2.0 support TMDS encoding for video transmission with the maximum bandwidth of 14.4Gbit/s

It support of HDCP (High Bandwidth Digital Content Protection) encryption protocol for copy protection

It includes dynamic lip-sync capability

Supports 4K/60 fps

It allows dual video streams to multiple users on the same screen

It supported wide angle theatrical 21: 9 aspect ration

2.0 enabled use of 8b/10b encoding

2.0 can deliver multi-stream audio to a maximum of four users

It is capable of delivering dual video streams to multiple users on the same screen.

1.4 b Specifications:

The 1.4b version also includes many minor numbers changes. It provided full HD for both pictures used for 3D 1080p video at 120Hz

1.4a Specifications:

It is a minor update that focused on the improvements of 3D video technology. In addition, it incorporated the 3 D broadcast formats that were not finalized during the earlier 1.4 version.

1.4 Specification:

Here are the following significant enhancements introduced in the 1.4 specifications:

What is HDMI Ethernet Channels:

High-Definition Multimedia Interface Ethernet Channels employed for high-speed networking. It allows the user to use all their IP-enabled devices without any additional networking Ethernet cable.

Audio Return Channel allows the connected TV with an in-built tuner to send audio data upstream to the surround sound audio system without any need for a separate cable.

3D:  1.4 defines input-output protocols for major 3D video formats.  It is the stepping stone for 3D home theater applications and 3D gaming. It supports many 3D techniques such as Full side-by-side Half side-by-side Frame alternative Field alternative Line alternative Left + Depth Left + Depth + Gfx + Gfx Depth and more.

4K support:

It provided 4k support to the devices, which enable video resolutions above 1080p. In addition, it supported digital displays, which are rival to the digital cinema systems.

Real-Time Content Signaling:

It enables real-time- content signaling to optimize the picture setting based on the content type. Besides, it allows automated and straightforward picture setting mode without user intervention.

Added Color Spaces:

It supports the additional color spaces for color models used in digital photography and computer graphics. Furthermore, it enables HDTVs to reproduce the digital cameras’ rich and natural life colors with consistency and accuracy.

Micro Connector:

It has a provision for the micro connector to connect phones and other portable devices.

Automotive Connection System:

Its new cables and connectors enable the automotive video system to deliver high-quality HD.

1.3a Specification:

1.3a was released for Cable and Sink modification for type C, source termination recommendations. It removed undershoot and maximum rise and fall time limits. However, it altered the CEC capacitance limit and commands for timer control. And, it enabled the optional ability to stream SACD in bitstream DST format instead of uncompressed raw DSD

1.3 Specification:

1.3 increased TMDS clock to 340 MHz of Bandwidth 10.2Gbits per second. The earlier versions allow the encoding given a maximum video bandwidth of 8.16 Gbits per second. The 1.3 version additionally added the ability to carry metadata defining color gamut boundaries. It allowed the Dolby TrueHD and DTS-HD Master Audio stream for external decoding by AV receivers. In additon, It incorporates automatic audio synchronizing capability. It defined cable categories one and two. The Category 1 cable tested up to 74.25 MHz, and Category 2 tested up to 340 MHz. 1.3 versions, added the new type C Miniature connector for portable devices.

1.2a Specification:

1.2a fully specifies the CEC (Consumer Electronics Control) features, command sets, and compliance tests. It helped the user to operate multiple devices with only one handled remote control unit.

1.2 Specification:

1.2 was released in the year 2005. It added options of One Bit Audio used in Super Audio SCs at a maximum of 8 channels. It modified the HDMI protocol to suit more to computer devices as well. Furthermore, it added manufacturers’ ability to employ vendor-specific formats allowing any arbitrary resolutions and refresh rates. Besides, it employed additional support to several new formats, including 720p at 100 and 120Hz, and modified the pixel format support to native RGB output.

1.1 Specification:

It was a minor update released to add support for DVD-Audio.

1.0 Specification:

HDMI 1.0 is the incarnation of HDMI, and it subsequently underwent many numbers revisions and updates.

It includes the basic HDMI capabilities in a single digital audio/video connector interface.

It employed the basic DVI link architecture concept that is needed for video streaming. In addition, its audio-video interface provided high-definition video transfer.

It has the provision for up to 8 channels of uncompressed digital audio. Have the data transfer up to 4.95 GB per second. And, it allows a maximum TMDS clock of 165MHz. Besides, it defines two connectors, A and B.

It uses TMDS encoding for video transmission offering 4.95 GB of Bandwidth.

In addition, it supported RGB video, and color depth of 30 bit/px or 36 bit/px is allowed when using 4:2:2 sub-sampling, but only 24 bit/px color depth is permitted when using RGB or YCbCr 4:4:4. It allowed only a few pre-defined video formats. Moreover,  it enabled playback of the blu-ray disc at the full resolution.

What are HDMI Connector Types:

There are five High-Definition Multimedia Interface connector types.

They are Type A, B, C, D, and E.  The connector can be directly connected to the device. They carry HDMI signals with TMDS. The type B connector additionally carries second TMDS data signals which are much needed for higher resolution displays using dual-link.

Therefore it is slightly larger.  Type C connector carries the same signal as type A. But it is smaller and compact intended for mobile applications.

Type A (Standard):

Types A and B are specified in the 1.0 version. The external dimension of the Male connector (Plug) is 13.9 mm × 4.45 mm, and the Female connector (Receptacle) inner dimension is 14mmx4.55mm. There are 19 pins with bandwidth to carry all SDTV, EDTV, HDTV, UHD, and 4k Modes.It is electrically compatible with single-link DVI_D.

Type B (Dual):

It is a connector of size 21.2 mm × 4.45 mm. Moreover, it has 29 pins. Besides, it carries six differential pairs instead of three for the use of high resolutions displays.

Type C (Mini):

It is defined in the HDMI 1.3 specification, and this mini connector is smaller than type A.  It is a connector of size 10.42×2.42mm. And it has the same 19-pin configurations. It is meant for portable devices such as Smartphones and digital cameras.  The C-type mini connector can be connected to a type “A” connector using a type A-to-type C cable.

Type D (Micro):

D is a micro connector. The connector resembles a micro USB connector.  The connector size is 11.5 mm × 4.5 mm. it has the standard 19 pins of type A or C. But the pin assignment of Type D is different from both A and C.

Type E (Automotive):

It is meant for automotive connection systems. It has a locking tab to keep the cable firmly connected. The locking tab keeps the cable in position firmly against any automobile vibration. The protection shell prevents moisture and dust particles from entering. Besides, a relay connector is available to connect the standard cable to the automotive type.

What are HDMI Male and Female Connectors:

The female connectors usually found built into both Source and Sink Devices. It is fixed as a socket intended for a male end cable to connect to it. Generally, the cable has male connectors at both ends.  They are directly plugged into the female sockets of the source and sink for power and data transmission. The female connectors have pins, and they cannot suffer a short circuit. Therefore, firmly fixed into the body of the gadgets.

What is HDMI Cables:

HDMI cable is four shielded twisted pairs with impedance with seven separate conductors. But the HDMI cables with Ethernet differ from Normal HDMI cables. There is no maximum length for the HDMI cable is specified.  The signal attenuation solely depends on the cable construction and material. Generally, 13m beyond signal attenuation may happen. The attenuation limits the length of the cable.

According to 1.4 specifications, cables are classified into the following five categories.

They are:

  • Standard Cable – up to 1080i and 720p
  • Standard Cable with Ethernet
  • Automotive HDMI Cable
  • High-speed HDMI Cable – 1080p, 4K 30Hz, 3D, and deeper color
  • High-Speed HDMI Cable with Ethernet

Earlier Version 1.3 specifies cable standards, and the cables categorized into Category one and Category two. Category – 1 marked as standard and Category- 2 marked as High Speed. A cable of 5 meters of category-1 can be manufactured inexpensively using 28AWG conductors with better quality construction materials. With high-quality construction materials with 24AWG conductors, a cable may reach a maximum of 15 meters for better quality. Tested category-2 cables can only give better results.

  • HDMI 2.0 specification standardized the cables into two types.

They are:

  • Premium High-Speed HDMI Cable
  • Premium High-Speed HDMI Cable with Ethernet

Further, the latest 2.1 version categorizes Ultra High-Speed HDMI Cable (48G Cable).

What is HDMI Licensing:

HDMI- High-Definition Multimedia Interface specification is not an open standard; manufacturers need to get a license from HDMI LLC to implement HDMI standards in any of their component products for a fee. The companies who authorized to use HDMI in their products are  HDMI Adopters.

HDMI Licensing Fee:

There are two fee structures associated with the HDMI adopter apart from the royalty fee.

For High volume Products, more than 10k units are 10K USD per year

For Low volume, less than 10k products are so 5k USD per year + One USD per unit

Royalty Fee for License:

  • 15 USD for each  product
  • 05 USD for each product if the HDMI Logoused on the product
  • 04 USD if HDMI Logo used and HDCP implemented at the product.

The royalty fee is payable on licensed products if sold as a standalone product directly sold to the customer.

What are HDMI Features:

TMDS or Transition-Minimized Differential Signaling Employed

Consumer Electronics Control (CEC) Feature

HDCP- High Bandwidth Digital Content Protection enabled

Display Channel Interface includes support for VESA DDC

Chroma Sampling Video compression employed

Support to Color Space and Deep Color with Color depth

Audio Return Channel enabled for minimizing cable use

HDMI Ethernet Channel (HEC) allows Ethernet-enabled devices to share Internet

Supports Dynamic HDR and High Dynamic Range

Enhanced Audio Return Channel (eARC) support for higher-quality audio bandwidth and speed

Display Stream Compression (DSC) support for uncompressed audio and video

No Compression

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