Distribution amps take an incoming video signal and split it into separate signals that are sent to multiple devices. These come in a range of sizes (1×4, 16×4, etc). Despite the name, few of thesedevices actually amplify the video signal. They separate and distribute a single input to several outputs. They do not increase the maximum cable distance.
A Distribution Amplifier takes one video input and replicates it to multiple outputs without loss of quality. In surveillance, it allows multiple monitors or recorders to receive the same camera feed simultaneously.