Vision mixer

A vision mixer (also called video switcher, video mixer or production switcher) is a device used to select between several different video sources and in some cases compositing (mix) video sources together to create special effects. This is similar to what a mixing console does for audio.

In most of the world, both the equipment and its operator are called a vision mixer or video mixer; however, in the United States, the equipment is called a video production switcher, and its operator is known as a technical director (TD).

Typically a vision mixer would be found in a video production environment such as a television studio, production truck, OB Van or linear video editing bay of a post-production facility.

Besides hard cuts (switching directly between two input signals), mixers can also generate a variety of transitions, from simple dissolves to pattern wipes. Additionally, most vision mixers can perform keying operations and generate color signals (called mattes in this context). Most vision mixers are targeted at the professional market, with newer analog models having component video connections and digital ones using Serial Digital Interface (SDI). They are used in live television with video tape recording (VTR) and video servers for linear video editing, even though the use of vision mixers in video editing has been largely supplanted by computer based Non-linear editing systems (NLE).

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