Programs enabling conversion of the file:
If your objective is to convert the file from MTS to the file M2TS, you can use any of the applications listed. MTS to M2TS conversion process in every program intended for this purpose (so-called converters) is very intuitive and everyone is able to manage converting a file.
However, bear in mind that the list may also include programs to support and work with the indicated extensions MTS and M2TS - and not only converters. In such a case, you need to open the source file MTS and from the options available in the program, choose ”Save as... M2TS" or "Export to M2TS".