An HDMI switch is used when there are not enough HDMI inputs. With a 3x1 HDMI switch, for example, you can operate 3 players on one monitor.
HDMI switches differ mainly in the supported video formats. Older switches often do not support Ultra HD resolution. Current HDMI switches support HDMI 2.0 and thus all film and video resolutions for streaming services. HDMI 2.1 is required for gaming with the latest game consoles or PC in the highest possible Ultra HD resolution of 4K 120Hz or 8k.
The output of the HDMI switch is connected to an HDMI input of a television, video projector, monitor or sound system. The HDMI inputs of the HDMI switch are connected to the HDMI outputs of the player, e.g. from the Apple TV, Fire TV, satellite receiver, Blu-ray player or computer.
Importantly, an HDMI-ARC connector can either be an HDMI input (on the TV) or an HDMI output (on the soundbar).
An HDMI 2.1 switch is best suited for operating the PlayStation 5 or Xbox Series X on a gaming monitor or a current Ultra HD television that supports 4K 120Hz. If fast-paced action games are not an issue or the screen / video projector does not support 4K 120Hz, an HDMI 2.0 switch is sufficient.
A splitter distributes the signal, eg 1 player to 2 TVs and does not require a remote control. A switch, on the other hand, works in reverse and switches between different sources, eg 3 players on one TV. The combination of HDMI switch and splitter is called HDMI matrix switch, so you can bring 4 players to 2 displays, for example.