In this article, we will deal with the key differences between all HDMI versions, supported resolutions, and "improvers" like HDR and Dolby Vision. You will also learn how to figure out which cable is needed for a 4K TV, which one for a gaming monitor, and which one for a projector.

How HDMI Works

A digital signal consists of a sequence of zeros and ones and does not have intermediate states, like an analogue signal. When transmitting a signal via HDMI, the encoded data is sent over a cable with a small margin so that the signal can be properly decoded if some of the zeros or ones are lost along the way. If the signal is transmitted so badly that this reserve is not enough, there will be no “useful” signal at all, and the TV will show unpleasant audio and video artifacts. If the disturbances in the signal exceed a certain level, the image and sound disappear completely.

HDMI 1.0 — 1.1


In the early 2000s, it became clear that there was no future for digital DVI. This digital standard had its own technological limitations, could not transmit audio, and was used primarily in computer monitors. We needed a single format that would allow home gadgets to communicate with each other in the same language. As a result, almost all the big shots from the video business world have allocated engineers to develop a single standard. So at the end of 2002, HDMI was introduced to the world.

The first version of the protocol allowed video at 1080p/60Hz and audio at 192kHz/24bit. The bandwidth of the channel was limited to 4.95 Gbps. Two years later, version 1.1 was released, which added support for sound protection, which is necessary for playing DVD-Audio. Don't forget about compatibility with DVI. Now you can use a DVI adapter to connect an HDMI-enabled device, be it a monitor or a TV.

HDMI 1.2 — 1.2a


In the summer of 2005, the next big update hit HDMI 1.2. There was support for Super Audio CD and a unified HDMI A connector, which is now suitable for use in both TVs and computer monitors. And all because he learned to work simultaneously with the "native" RGB palette for monitors, and with the YCbCr television palette.

Just a few months later, in the winter of 2005, a small HDMI 1.2a update arrived, the main innovation of which was certification in accordance with the CEC (Consumer Electronics Control) standard. From now on, cable manufacturers were required to carefully approach the testing of cables and the use of connectors.

HDMI 1.3 — 1.3b


With the release of version 1.3, the protocol moved to the next stage of development, becoming the main one for those versions of HDMI that we are used to seeing today. News of the day: throughput has more than doubled. It was 4.95 Gbps, it became 10.2 Gbps. So the new version allowed to transfer a picture in a resolution of 1920x1080 at a refresh rate of 120 Hz, or 2560x1440 at a base 60 Hz. There is support for 10/12/16-bit colour depth, as opposed to 8-bit colour depth in previous versions of HDMI. HDMI has become the de facto industry standard, and many of these numbers are still relevant today, almost 15 years later.

In addition, it was in this specification that a special small-sized connector was developed for use with photo and video cameras. Around this time, doctors diagnosed the death of conventional DVDs, so the HDMI specifications added support for the DTS-HD Master Audio and Dolby True HD audio codecs that were used in Blu-Ray and HD DVD.

A year later, a consortium of developers rolled out a small and uninteresting for the average user update HDMI 1.3b, which changed several highly specialized details like CEC specifications.

HDMI 1.4 — 1.4b


And now, after 7 paragraphs of text, we finally got to the current version of HDMI, which is still actively used in technology. The main innovation is the support for high-definition content, which will become really relevant only ten years later. The limits on the refresh rate became a fly in the ointment, in 4K we could transmit an image with a frequency of no higher than 30 Hz.

HDMI also acquired a bidirectional data transfer channel, which made it possible to work with Ethernet devices and transmit an audio signal in two directions: for example, from a TV to a receiver and vice versa. Other innovations include Automatic Content Enhancement (ACE) and optimization of the picture settings on the TV screen in accordance with the type of material. Together with versions 1.4, a new compact Micro-HDMI connector was presented.

Versions 1.4a and 1.4b focused on supporting 3D video: first, content and technology led to more stringent quality standards, then HDMI learned to transmit 3D content at 1080p resolution at a refresh rate of 120 Hz.

HDMI 2.0 — 2.0b


With the release of the second version, the HDMI format finally stepped into a bright future, in which everyone watches videos in 4K, and 60-Hz monitors are found only in the museum of technology. The main news is that a picture in 4K can now be transmitted at a frequency of 60 Hz and 24-bit colour reproduction. Yes, there was support for high resolution before, but 24 or 30 Hz was good for traditional movies and TV shows, but not very suitable for dynamic content like video games or sports broadcasts. Among other innovations, stand out support for displays with non-traditional proportions like 21:9.

Subsequent versions (2.0a, 2.0b) first added support for HDR content, then improved its implementation.

HDMI 2.1


HDMI 2.1 is the biggest protocol upgrade since 4K and 3D. This version was called Ultra High Speed and learned how to stream video in 8K and 10K resolution. At the same time, refresh rates have been tightened up at the popular 2K and 4K resolutions, both transmitted at 120 Hz, meeting all the requirements of next-gen consoles and games of the future. But this is only on the surface, if you dig deep, then there are much more interesting innovations.

So Variable Refresh Rate (VRR) reduces or eliminates lag, judder, and frame tearing for a smoother, more detailed gaming experience. The technology for reducing the delay of Quick Frame Transport works in a similar vein. Potentially, these are extremely important features for the games of the future. Based on VRR, QMS Quick Media Switching technology was created, which eliminates interference when changing the refresh rate in streaming video.

Oh yes, the new format allowed all movie lovers to taste the delights of HDR content. If earlier we were lured by the usual HDR, now it has been replaced by the new Dynamic HDR (HDR +) standard. If conventional HDR puts everything under the same brush, setting the same colour rendering brightness parameters for all frames, dynamic HDR selects the optimal values not just for each specific frame, but for its different areas. Therefore, the picture in the Dynamic HDR format looks both very rich and natural at the same time.

HDMI A, C and D: what's the difference?


Having gone through all the versions of HDMI, it would be wrong to ignore the connection types. Over the years of the existence of this standard, he has acquired five different types of connectors. HDMI A is a well-known classic. HDMI B was needed to transmit a two-channel signal, but became unnecessary with the release of version 1.3. Types C and D were created to reduce the size of the port, similar to mini and microUSB. Well, type E with an optional protective connector is designed for industrial use and is rarely found in household stores.