Programs enabling conversion of the file:
If your objective is to convert the file from FLV to the file 3GP, you can use any of the applications listed. FLV to 3GP 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 FLV and 3GP - and not only converters. In such a case, you need to open the source file FLV and from the options available in the program, choose ”Save as... 3GP" or "Export to 3GP".