The main functionality of a video switcher is for creating a master output for real-time video broadcast or recording. They can create different visual effects, ranging from simple mixes and wipes to elaborate effects. They can also perform keying operations and help in producing color signals. Video switchers work similarly to audio mixers. They make use of multiple input sources, then apply the desired effects and produce one or more outputs.

Most video switchers are based around program and preview bus, which each has its own monitor. The program bus is the main output feed, whereas the preview bus is for choosing and previewing the source that is about to go live. Using the preview bus is optional. However, the preview bus is needed in the case of any visual effects. A modern video switcher has additional features like the ability to store complex mixer configuration as well as serial communications with the ability to make use of proprietary communications protocols.