Split n Join allows you to split and combine specific types of files. Split n Join adds four more components to SplitMe, another software title we develop, to let users combine files. Use SplitMKV to split a single Matroska movie into multiple independent movie clips, each of which can be opened. JoinMovie allows users to combine independent movie clips into one QuickTime movie, which can be saved, imported back and then exported to create a self-contained, multiplexed QuickTime movie. Likewise, users can combine multiple independent audio clip into one, which can be exported to create a joint audio clip. JoinImg deals with a set of split DMG segments. Use JoinImg to put DMG parts together to create a single disc image to restore the original state before it was split.
A User's Guide is available here.