If you are looking for an alternative for expensive industrial DVD players, MultiScreener is your software.
MultiScreener is a program for synchronizing the playback of a QuickTime video on several machines through a local network. With this tool, it is also possible to synchronize several films on the same machine with multiple monitors. It includes a Server and a Client. The first one plays and sends the film over the network while the second one listens to it and adapts its playback speed.