HDMI 2.0 extends bandwidth up to 48Gb/s for high frame rate and high resolution video.
A quick look at the lens to display pipeline highlights some trivial-seeming bottlenecks that place important constraints on motion imaging systems. One of these is the connection to the consumer display. The announcement of HDMI 2.1 is key to advancing to 4K and beyond, with additional support for HDR, and increased frame rates for UHD video.
The HDMI Forum has announced the release of the HDMI 2.1 specification. Supporting a bandwidth up to 48Gb/s, it is a big increase over the 18Gb/s of the previous HDMI 2.0 and over 4x the bandwidth of HDMI 1.4, which is still commonplace in the home.
The wider bandwidth now supports 8K to 60fps and 4K to 120fps. Resolutions up to 10K are also supported for other applications.
As developers of HDR transmission soon found, without the release of HDMI 2.0, it was difficult to display UHD video without multiple connectors, a no-no for consumer applications. The first UHD content I saw was on a monitor with four DVI connectors, carrying four HD quadrants.
It wasn’t just the video bandwidth either, support for HDR static metadata (added in 2.0a) and HLG signalling (2.0b) also awaited updates to the interface specification. HDMI 2.1 now adds support for dynamic HDR metadata.
Dynamic HDR support ensures every moment of a video is displayed at its ideal values for depth, detail, brightness, contrast and wider color gamuts—on a scene-by-scene or even a frame-by-frame basis.
The step from 1.4 to 2.0 was key for UHD displays, increasing the frame rate for 4K images from 24fps (OK for movies) to 60 fps for the new higher frame rate UHD sports programming. 2.1 now means that all the planned HDR features can be utilized in the next generation of displays.
A new cable specification was required for such a high speed interconnection. It should exhibit exceptionally low EMI (electro-magnetic interference) which reduces interference with nearby wireless devices. The cable is backwards compatible and can be used with the existing installed base of HDMI devices. The Forum designates the maximum speed of HDMI cables as follows:
|Designation||Data Rate||Typical application|
|Standard||2.23 Gb/s||1080P30 and 1080i60|
|High Speed||8.9 Gb/s||1080P60 and 2160P24|
|Premium||17.8 Gb/s||2160P60, 8, 10 &12 bit 4:2:2|
|Ultra||48Gb/s||2160P120 12 bit 4:4:4|
To support the higher data rates a new 'Ultra' cable is specified.
Since the connector form-factor is basically the same, the label—Ultra or whatever—indicates whether that cable will support the necessary video data rate. Consumer beware! Many of the early adopter of UHD display riushed out and purchased receivers with 1.4 connectors, and soon found that they are not much use for watching 50 or 60 fps sportscasts.
Display Stream Compression (DSC)
Resolutions up to 8K (4320P120) are supported with DSC, a Video Electronics Standards Association (VESA) standard. DSC is visually lossless compression that is also used with DisplayPort connections.
You might also like...
Timing is the most fundamental aspect of broadcast television. From the early days of tube cameras, to modern OLED displays, timing continues to play a crucial role for maintaining an optimal viewer experience. Picture stutter and breakup are just a…
The World Cup games brought surprises aplenty for millions of soccer fans from around the world. As the teams clashed, the Fox Network handled the U.S. broadcasts.
Most CDNs (Content Delivery Networks) and the video streaming services they support have coped well with the peak time loads of the current FIFA World Cup, beyond a few well publicized glitches.
The Cloud itself is pretty simple, but for broadcasters, leveraging it can be complex. It isn’t that difficult technically, but Broadcast still straddles requirements that demand real time, high resolution, quick turnaround solutions; and this is coupled with the n…
For the first time in the history of live television we can now abstract away the video, audio, and metadata streams from the underlying hardware. This innovation presents unprecedented opportunities empowering broadcasters to deliver flexibility, scalability, and highly efficient workflows.