Converting .3pg files to .h264 format.
Converting 3PG Files directly to H.264 Encoded Video Files (.3pg to .h264 conversion) is not possible, since 3PG is not an existing format.
We are not aware of any available media editing software or (online) conversion tool capable of converting .3pg to .h264.
Perhaps this was just a typo in your search field, and you were, in fact, searching for ways how convert .3gp to .h264.
In a word, direct 3pg to h264 conversion is not possible.
So don't expect any so-called 3pg to h264 converter or 3pg to h264 free online conversion tool available.
The database currently does not contain any 3pg software converter.