HDBaseT

showstack / protocols / hdbaset

Also called 5Play.

Uncompressed ultra-HD video and audio, 100 Mbit/s Ethernet, USB, control and up to 100 W of power over a single category cable — the "5Play" set. It is how an HDMI signal gets from a rack to a projector 90 m away without fibre.

Video transportProprietary, documentedHDBaseT AllianceReported

Media Large, continuous, on time and in order

Continuous streams that are large enough to be sized properly, and that must arrive in order and on time.

What kills it. Anything that starves the link — usually a management transfer nobody scheduled — and jitter that outruns the receive buffer.

The four flows, and why the model is worth having →

What it carries

Resolution: 3840x2160
Frame rate: up to 60 Hz
Colour sampling: 4:2:0, 4:4:4
Video compression: Uncompressed

Audio: HDBaseT fixes no audio format of its own. It transports the HDMI stream, so the audio capability is whatever that HDMI version defines, and a question about channel counts or sample rates is a question about the source and sink rather than about the cable between them.

Video: Version decides which of those you actually get. HDBaseT 1.0 and 2.0 reach 4K60 only at 4:2:0; 3.0 roughly doubled the downstream rate and carries 4K60 at 4:4:4. Two bandwidth figures circulate for 3.0 and they are not the same thing — 16 Gbit/s is the link rate, not the usable video payload.

What goes wrong

It uses category cable and RJ45 connectors and is not Ethernet. Putting an HDBaseT link through a network switch does not work, and the cable should be a dedicated point-to-point run.

Cat6 is the practical baseline. Cat5e reaches shorter distances, and shielded cable and proper terminations matter far more here than on a data network where retries hide small problems.

Distance figures are quoted for specific formats. The 100 m figure is not the distance for every resolution and colour depth.

Power over the link is not PoE and is not interoperable with it.

Typical use

Projector and display feeds over structured cable
Distributing switched video around a venue
Extending control and Ethernet alongside the picture on one cable

Sources

HDBaseT Technology — HDBaseT Alliance primary

Understand the mechanism

Why the picture is black

Something wrong, or missing?

Known gaps on this entry: default_ports, first_published, implementations. If you can source one of them, that is a ten minute pull request.

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