m4v file change header position in the file.

[tidi]

Hello!

I've got a couple of files, one with the header at the beginning and another one with the header at the end of the file.
The files are mpeg4+aac into an m4v container.

How can I move the header (moov etc..) of an m4v file at the the beginning?

ffmpeg, MP4Box or something else?

Thanks for the help.