Before introducing HDMI, let's talk about the DVI interface. DVI is the earliest common interface for digital video transmission, but if you want to output an audio signal, you need to connect an additional audio cable, so you can only use one cable to transmit at a time?
What about digital video and audio signals? HDMI came up with this requirement. HDMI has inherited TMDS (Transition Minimized Differential Signaling) transmission technology from DVI and can also transmit digital audio signals. What is HDMI? The full name of HDMI is High Definition Multimedia Interface. It is an all-digital video and audio transmission interface capable of transmitting uncompressed audio and video signals.
1.HDMI1.0-1.3
- HDMI1.0 was officially released on December 9, 2002, marking the official entry of HDMI technology into history.
- Supports Full HD 1080/60p (i.e. 1920*1080 resolution, 60hz refresh rate) image transmission.
- Supports video streaming from DVD and Blu-ray formats with a bandwidth of up to 4.95 Gbps at high frequency.
- Compatible with the DVI-D interface as it uses the same TMDS transmission technology.
- HDMI1.1 released in May 2004 with support for DVD-Audio.
- HDMI1.2 was released in August 2005, adding support for up to 8 channels of SACD audio streaming.
- HDMI1.3 was released in June 2006, the color depth was extended from 24 bits to 30 bits, 36 bits or 48 bits (RGB or YCbCr).
2.HDMI1.4
- Released June 2009, the most widely used specification.
- 4K resolution is supported for the first time, but only 4096 x 2160/24p or 3840 x 2160; 2160/24p/25p/30p "fake 4K".
- Supports 1080/24p, 720/50p/60p 3D images.
- Added 100Mbps network transmission function.
- Added the ARC (Audio Return Channel) function, which allows the TV sound to be returned via HDMI for output to the power amplifier.
- HDMI 1.4a, released March 4, 2010, defines a mandatory 3D format for broadcast, gaming, and movie content.
- HDMI 1.4a defines a mandatory 3D format for TV, game and movie content.
- HDMI 1.4b was released on October 11, 2011, with only a few notes on version 1.4a.
3.HDMI2.0
- Released September 2013.
- Data bandwidth has been increased to 18 Gbps.
- Supports 3840×2160 resolution and 50FPS or 60FPS frame rate, officially ushering in the "true 4K" era.
- Supports plug and play and hot swap.
- Audio support up to 32 channels and sample rate up to 1536kHz.
- HDMI 2.0a was released on April 8, 2015, adding support for High Dynamic Range (HDR) video with static metadata.
- HDMI 2.0b, released March 2016, adds support for HDR video transmission, advanced static metadata signaling, including Hybrid Log Gamma (HLG).
4.HDMI2.1
- Released November 2017.
- The data bandwidth has been increased to 48 Gbps, which is more than double that of HDMI2.0.
- With this high bandwidth, high resolutions of 7680×4320@60Hz (8K@60hz) and 4K@120Hz can be supported.
- The introduction of dynamic HDR technology can better reflect the light and shadow effects of the picture.
- DSC1 support.2 video compression option that can compress video data
- In terms of audio, the eARC technology has been improved. Compared to the existing ARC (Audio Return Channel), the transmission bandwidth has been expanded from less than 1Mbit/s to 37Mbit/s, so that object-based sound effects such as Dolby Atmos can be played back.
- Automatic Low Latency Mode (ALLM) - If the display device supports the option to optimize its pixel processing for the best latency or pixel processing, ALLM automatically enables the current HDMI source device due to its better understanding of the nature of its own content select the mode that best suits the user.
The above is related to the development process of HDMI. With the generation-to-generation upgrade, the current HDMI2.1 protocol can already meet the transmission needs of many consumers.
