HDMI carries digital audio and video over one connection, but not every port or cable supports every capability. If you use a console, streaming device, soundbar, or receiver, check the specifications for both ends of the connection. A device can only use a feature when the display, source, and connection path all support it.
Look for labels that identify enhanced bandwidth or audio return features, and consult the device manuals when port names are unclear. HDMI ARC and eARC let compatible televisions send audio back to a soundbar or receiver through an HDMI connection. For a console or computer, features such as high refresh rates depend on the capabilities of the display and the selected port, not simply the cable's appearance.
Choose a certified cable appropriate for the distance and signal requirements, and avoid unnecessary adapters or long cable runs when troubleshooting. Connect the devices firmly, select the correct input, and enable any required format or enhanced-input setting in the menus. If a screen stays blank or audio disappears, test one device and cable at a time. Restarting connected equipment can also help it renegotiate the connection.
Understanding HDMI Versions, Cable Types and Handshake Problems
Much of the confusion around HDMI comes from version numbers. Labels such as HDMI 2.0 and HDMI 2.1 describe the capabilities a device may support, not features every port is guaranteed to have. A television advertised as HDMI 2.1 might offer 4K at 120Hz or Variable Refresh Rate on only one or two of its inputs, while the remaining ports behave like older connections. That is why the port labels and the spec sheet matter more than the headline version number.
Matching the cable to the job
HDMI cables are sold under certification names that map roughly to bandwidth:
- High Speed: suits most 1080p and many 4K at 60Hz setups.
- Premium High Speed: certified for 4K HDR at 60Hz with fuller colour detail.
- Ultra High Speed: intended for the higher bandwidth of HDMI 2.1 features such as 4K at 120Hz and 8K.
Expensive gold plating or thick braiding does not improve a digital signal. A cable either carries the data reliably or it produces dropouts, sparkles or a blank screen. For longer runs, often beyond around five metres, active or fibre-optic HDMI cables tend to be more dependable than passive copper, though fibre models usually work in one direction only, so check which end goes to the source.
Why handshakes fail
Every time devices connect, they exchange information about supported resolutions, audio formats and copy protection, a process known as the HDMI handshake. HDCP, the copy protection layer, is a frequent cause of trouble: if any device in the chain, such as an older receiver or a cheap splitter, lacks the required HDCP version, protected content may refuse to play. Powering devices on in a consistent order, usually display first and source last, can reduce these issues.
HDMI-CEC and convenience features
CEC lets one remote control several devices and can switch inputs automatically. Manufacturers rename it, so look for terms like Anynet+, Bravia Sync or SimpLink in the settings. If devices turn on unexpectedly or inputs jump around, disabling CEC on one device is a sensible test.
If you are building a home theatre, our guide on what to look for in a soundbar explains how ARC and eARC fit into audio choices, and choosing a 4K TV covers which input features are worth prioritising.