OnTheAir Live is a playlist manager for Live productions that comes bundled with OnTheAir Node and provides the user interface for adding media and controlling playback. As its name implies, OnTheAir Live has all the features required for Live operations such as Cue mode, A/B roll, GPI triggers, etc...
Note that it is a free application but it doesn't output video. It is a client application that requires a OnTheAir Node to run on the network. OnTheAir Node is the application that will output video.