MP4Tools is a collection of cross-platform free tools to manipulate MP4 files.
It contains following applications:
⦁ MP4Joiner is a free application that allows join multiple MP4 files into one
⦁ MP4Splitter is a free application that allows split a MP4 file in multiple files
Does exactly what it says, but there is a lot of adaware delivered with it. Make sure you always choose "Skip" or "Decline" when asked.