What component combines multiple video channels into a single output?

The correct answer is the multiplexer. A multiplexer is a device that takes multiple video inputs and combines them into a single video output. This technology is particularly valuable in surveillance systems, where multiple camera feeds need to be monitored and recorded without requiring individual outputs for each camera.

By using a multiplexer, all video streams can be transmitted to a single display or recording device, simplifying system management and enhancing the user’s ability to monitor different areas simultaneously. This capability allows for efficient use of resources and makes it easier to manage a large number of cameras, as the operator can switch between different feeds or view them all at once through a single interface.

Other options serve different purposes; for instance, a DVR (Digital Video Recorder) is primarily designed to record video, whereas a VCR (Video Cassette Recorder) is a legacy technology used for recording and playing back analog video. A camera captures video images but does not combine multiple channels. Therefore, the multiplexer is the key component essential for integrating various video feeds into a cohesive output.