It should be quite possible to convert H264 based videos to common 3G2 (3GP) format using programs like Adapter. However, this could also be done with any other converter that supports various 3GP formats, so maybe check for H264 to 3GP conversion as well.
Convert H.264 video to 3GPP2 multimedia file.
We found 2 software records in the database related to .h264 to .3g2 file format conversion.
Apple macOS / Mac OS X software - convert h264 to 3g2 on OS X
A free video converter for Mac & PC
Convert from h264 file format
|Yes, Adapter supports h264 file conversion as a source file type.||No||No||No||No||No||No||No|
|Yes, Adapter supports 3g2 file conversion as a target file type.||No||No||No||No||No||No||No|
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned h264 to 3g2. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
Multiplatform software - convert h264 to 3g2 on any platform
Program for multimedia streaming and conversion