How it works
HDMI connects a source such as a computer or media player to a display and can carry audio on the same link. The usable picture mode depends on the source output, selected screen input, cable and intermediate equipment. A television may offer different capabilities on different sockets. HDMI connector shape alone does not identify the highest supported resolution, refresh rate, colour format or optional feature.
Audio return functions, variable refresh and other capabilities must be supported by the relevant devices and connections. A cable that works for a modest mode can still fail at a more demanding combination. Conversely, a blank picture can come from choosing the wrong input or an unsupported setting rather than a damaged cable. An HDMI splitter duplicates or distributes signals; it does not automatically create independent extended desktops.
Practical checks
Identify both device models, the connected sockets and the cable's certified capability. Test a direct connection before adding a receiver, dock or switch. Select the intended input and begin with a supported picture mode, then change one setting at a time. Check audio output separately if the picture works but sound does not. Use the documentation for the exact combination instead of assuming that a version label guarantees every optional function.