Combining Two QuickTime Movies into One
With QuickTime Pro, you can easily add one movie to another to make one longer
To combine two movies:
In QuickTime Player, choose Edit > Select All to select the entire contents of the first
Choose Edit > Copy, then open the second movie.
Move the playhead to the point at which you want to insert the movie (usually the very
beginning or end of the original movie), and choose Edit > Paste.
Choose File > Save As to name and save the new movie.
Editing and Authoring with QuickTime Pro