App for play live videos?

[umbilical]

hi there, I help a band, I projection some animations in a big screen when they play live, I use dvd player, beacuse they help to show in full screen in a big monitor... the controls I have in the macbook... but I need a software that help me of this way:

by example I play 1 video, in the middle of the song I need insert another video with some transition... you know make changes in the videos, the problem is that some days the band play more fast or more slow depends of the mood ... so I need match the videos with the music?

any app for make that video changes when play live?

thanks