High Definition Multimedia Interface (HDMI) is a fully digital video and sound transmission interface that can simultaneously transmit uncompressed video and audio signals, and uses the same wire for transmission, which greatly simplifies the installation difficulty of the system line, so it is widely used, such as TVs, set-top boxes, DVD players, computer and monitor connections, projectors, game consoles, audio equipment, etc.
The HDMI interface first appeared in 2002 and was jointly initiated by seven companies including Sony, Hitachi, Panasonic, Philips, Toshiba, Siliconimage, and Thomson. It can transmit video and audio signals at the same time, and the quality is very high.
Common types of HDMI interfaces
The maximum data transmission speed of HDMI connection devices is 48Gbit/s, and there is no need for D/A or A/D conversion before signal transmission. You can learn about the five common interface types, namely HDMI A, B, C, D and E.
1.HDMI A Type:
This is the most popular choice on the market. It has 19 pins, a width of 13.9mm and a thickness of 4.45mm. It has similarities with DVI single-link transmission and is present in most audio-visual devices we encounter in our daily lives. And the HDMI A Type interface has the fastest transmission speed. It supports a maximum data transmission speed of 5Gbps, which can meet the transmission needs of video data in high definition, high picture quality and high resolution.
2.HDMI B Type:
Although uncommon, it is highly valued in professional settings. With its 29-pin design and 21mm width, it has excellent data transmission capabilities. To be precise, compared with the HDMI A interface, it has twice the data transmission capacity, equivalent to DVI Dual-Link, which is comparable to the highly respected DVI dual-link technology. Since most audio and video equipment operates at frequencies below 165MHz, and HDMI B Type operates at frequencies above 270MHZ, it is more common in professional application scenarios, such as resolutions above WQXGA 2560×1600. It is mainly used in professional equipment, such as professional monitors, cameras and other equipment.
3.HDMI Type C:
Often called Mini HDMI, it is mainly designed for small devices. It also has 19 pins, a width of about 6.5 mm, and a thickness of 2.4 mm, much like a Mini USB interface. It is nearly 1/3 smaller than Type A and is mainly used in portable devices, such as digital cameras, portable players, and other devices. Due to size limitations, some graphics cards use mini-HDMI, and users must use an adapter to convert it to the standard size Type A before connecting to a monitor.
4. HDMI D Type:
Also known as Micro HDMI - an improved version of Mini HDMI. This interface is only 6.4mm wide, 2.8mm thick, and has 19 pins, similar to Mini USB. This elegant and slim design enhances the user-product interaction experience.
5. HDMI Type E:
Mainly used for audio and video transmission of in-car entertainment systems. Mainly used for audio and video transmission of in-car entertainment systems. Due to the instability of the in-car environment, HDMI Type E is designed to be shock-resistant, moisture-proof, high-strength resistant, and able to withstand a wide temperature range. In terms of physical structure, it adopts a mechanical locking design to ensure contact reliability.
These HDMI interfaces are not fully compatible with each other, that is, Type A head cannot be connected to Type B head through an adapter, and Type B head cannot be converted to Type C head. However, since Type A head and Type C head only differ in physical size, they can be compatible through conversion devices.
Evolution of HDMI versions
- HDMI 1.0: Launched in December 2002.
- HDMI 1.1 / 1.2
- HDMI 1.1
Support DVD-Audio
- HDMI 1.2
Proposed in August 2005
Support 8-channel 1-bit audio (for SACD users)
Allow PC sources to use HDMI Type A connector
Enable PC sources to use native RGB color space while maintaining YCbCr CE color space
Require HDMI 1.2 and above monitors to support low-voltage sources
- HDMI 1.2a
Proposed in December 2005
Fully establish the functions, command set, and compatibility test procedures of the CEC channel
- HDMI 1.3
Proposed on June 22, 2006
Expand the bandwidth of single-link mode to 340 MHz (data transmission speed 10.2 Gbps)
Expand support from 24-bit color space (16.77 million colors) to 30-bit, 36-bit, and 48-bit (RGB or
Supports the new xvYCC color standard
Supports automatic voice synchronization (lip sync)
Supports Dolby TrueHD and DTS-HD Master Audio signals to an external decoder ([3])) If the player has the ability to decode these two signals directly, it does not need to support HDMI 1.3, because all HDMI specifications can send uncompressed audio signals.
Introduced a new miniaturized connector to support compact camcorders
The Sony PlayStation 3 was the first HDMI 1.3 player to be launched.
The Sony BRAVIA KDL- 46X2500 and KDL-40X2500 were the first HDMI 1.3 monitors to be launched. (1080p supports the new xvYCC color standard, 36 bits deep color)
EPSON EMP-TW1000 is the first HDMI 1.3 projector to be launched (supports 30-bit deep color)
- HDMI 1.3a
Proposed on November 10, 2006
Modify the HDMI C Type connector of Cable and Sink
Source termination suggestion
Remove the maximum and minimum limits of rise time and fall time
Change CEC capacitor limit
Clarify the RGB image quantization range
Add CEC instructions on time and sound control
Released certification test specification file at the same time
- HDMI 1.3b
Proposed on March 26, 2007
Mainly modify the HDMI Testing specification, while the HDMI Specification is still HDMI 1.3a. So it is the first time that the main HDMI Specification and the Testing Specification are different versions.
- HDMI 1.3b1
Proposed on August 1, 2007
Only minor changes were made to the fixture of the Type C connector on the test equipment
- HDMI 1.3c
Proposed on July 25, 2008
Like 1.3b and 1.3b1, it is a test standard developed for 1.3a
The main difference from previous versions is the cable test (adding cable test items or modifying their contents will help the interconnection compatibility of HDMI devices)
Some modifications are also related to repeaters and CEC
- HDMI 1.4
Proposed on May 28, 2009
Added HDMI 100M Ethernet channel, allowing Internet-based HDMI devices to share Internet access with other HDMI devices without connecting another Ethernet cable.
Added Audio Return Channel (ARC, Audio return channel), allowing HDTVs to independently transmit audio signals to A/V amplifiers and receivers and audio equipment for output via HDMI cables.
Defines universal 3D formats and resolutions. Standardize the input and output of home 3D systems, supporting up to two video streams with a resolution of 1080p.
Support up to 4K×2K (3840×2160p@24 Hz/25 Hz/30 Hz or 4096×2160p@24 Hz)
Expand the color space support, which is specially designed for digital cameras, including sYCC601, Adobe RGB, AdobeYCC601, which can display more accurate and realistic colors when connecting digital cameras.
Add Micro HDMI mini interface, which will be about 50% smaller than the current 19-pin ordinary interface.
Support car connection system, a cable specification designed for in-vehicle high-definition content transmission, which can avoid the influence of common environments such as heat, vibration, noise, etc. in the car, and also provide a practical solution for car manufacturers to transmit high-definition content in the car. (Page archive backup, stored in the Internet Archive)
- HDMI 1.4a
Proposed on March 4, 2010
Added Top-and-Bottom format
Added two sets of mandatory 3D picture transmission format standards for broadcast systems
Side-by-Side Horizontal
Top-and-Bottom
Define mandatory broadcast, game, and movie 3D standards
HDMI 1.4a standard requirements
3D display device frame encapsulation level must reach 720p@50, 1080p@24 or 720p@60, 1080p@24
Side-by-Side Horizontal must reach 1080i@50 or 1080i@60
Top-and-bottom must reach 720p@50, 1080p@24 or 720p@60, 1080p@24
- HDMI 1.4b
Proposed on October 11, 2011
Support 3D 1080p 120Hz
- HDMI 2.0
Proposed on September 4, 2013
Added 2160p@50 YCbCr 4:2:0, 2160p@60 YCbCr 4:2:0 (4K resolution)
Support 21:9 aspect ratio
32 channels, 4 audio streams
Transmission bandwidth 18Gbit/s
Cable compatible with HDMI 1.4 (no new data cables and connectors defined)
Support CEC extension
Support dual screen
Dynamic automatic sound and picture synchronization
- HDMI 2.0a
Proposed on April 8, 2015
Support high dynamic range imaging (HDR)
- HDMI 2.0b
Proposed in March 2016 Supports the transmission of high dynamic range imaging (HDR) video Bandwidth up to 18Gbps 4K @ 50 and/ 60 (2160p), which is 4 times clearer than 1080/60 video resolution Up to 32 audio channels for a multi-dimensional immersive audio experience Highest audio fidelity up to 1536kHz audio sampling frequency Simultaneous delivery of two video streams to multiple users on the same screen Simultaneous delivery of multiple audio channels to multiple users (up to 4) 9 video aspect ratios: 21 support for wide-angle drama Dynamic synchronization of video and audio streams CEC extensions provide more extended commands and control of consumer electronic devices through a single control point
- HDMI 2.1
Proposed on January 4, 2017 HDMI 2.1 adds support for "dynamic metadata" according to a white paper written by Philips
In short: "HDMI 2.0A covers HDR EOTF signaling and static metadata Dynamic metadata is covered by HDMI 2.1."
HDMI 2.1 additional features: (([5]))(([6]))
Maximum resolution supported is 10K/120 Hz
Supports 120Hz refresh rate at 4K, 8K, 10K resolutions
HDMI Version Comparison
· · Standard HDMI
· · High Speed HDMI
· · Ultra High Speed HDMI (48G)
Standard HDMI cables can optionally support HDMI version-specific sub-technical specifications, while High Speed HDMI cables support all specifications, such as Deep Color and xvYCC. Both standard and high speed HDMI cables can optionally support Ethernet. HDMI 2.1 version provides a new 48G cable specification that includes all functions.
| HDMI version | |||||
|---|---|---|---|---|---|
| 1.0–1.2a | 1.3–1.3a | 1.4–1.4b | 2.0–2.0b | 2.1–2.1b | |
| Release date |
|
|
|
|
|
| Signal specifications | |||||
| Max. transmission bit rate (Gbit/s) | 4.95 | 10.2 | 10.2 | 18.0 | 48.0 |
| Max. data rate (Gbit/s) | 3.96 | 8.16 | 8.16 | 14.4 | 42.0 |
| Max. TMDS character rate (MHz) | 165 | 340 | 340 | 600 | — |
| Data channels | 3 | 3 | 3 | 3 | 4 |
| Encoding scheme | TMDS | TMDS | TMDS | TMDS | 16b/18b |
| Encoding efficiency | 80% | 80% | 80% | 80% | 88.8% |
| Compression | – | – | – | – | DSC 1.2a (optional) |
| Color format support | |||||
| RGB | Yes | Yes | Yes | Yes | Yes |
| Y′CBCR 4:4:4 | Yes | Yes | Yes | Yes | Yes |
| Y′CBCR 4:2:2 | Yes | Yes | Yes | Yes | Yes |
| Y′CBCR 4:2:0 | No | No | No | Yes | Yes |
| Color depth support | |||||
| 8 bpc (24 bit/px) | Yes | Yes | Yes | Yes | Yes |
| 10 bpc (30 bit/px) | Yes | Yes | Yes | Yes | Yes |
| 12 bpc (36 bit/px) | Yes | Yes | Yes | Yes | Yes |
| 16 bpc (48 bit/px) | No | Yes | Yes | Yes | Yes |
| Color space support | |||||
| SMPTE 170M | Yes | Yes | Yes | Yes | Yes |
| ITU-R BT.601 | Yes | Yes | Yes | Yes | Yes |
| ITU-R BT.709 | Yes | Yes | Yes | Yes | Yes |
| sRGB | No | Yes | Yes | Yes | Yes |
| xvYCC (601 and 709) | No | Yes | Yes | Yes | Yes |
| sYCC601 | No | No | Yes | Yes | Yes |
| Adobe YCC601 | No | No | Yes | Yes | Yes |
| Adobe RGB (1998) | No | No | Yes | Yes | Yes |
| ITU-R BT.2020 | No | No | No | Yes | Yes |
| Audio specifications | |||||
| Max. sample rate per channel (kHz) | 192 | 192 | 192 | 192 | 192 |
| Max. aggregate sample rate (kHz) | ? | ? | 768 | 1536 | 1536 |
| Sample size (bits) | 16–24 | 16–24 | 16–24 | 16–24 | 16–24 |
| Maximum audio channels | 8 | 8 | 8 | 32 | 32 |
| 1.0–1.2a | 1.3–1.3a | 1.4–1.4b | 2.0–2.0b | 2.1–2.1b | |
| HDMI version | |||||
HDMI resolution and refresh rate limitations for each version
Parameter comparison of various versions of HDMI
