It should be quite possible to convert 3GPP videos to M4V format using video converters like Movavi Video Converter.
Convert 3GPP Third generation partnership project movie to MPEG-4 video file format.
We found 2 software records in the database related to .3gpp to .m4v file format conversion.
Microsoft Windows software - convert 3gpp to m4v on Windows
A fully-featured video conversion program
Convert from 3gpp file format
|Yes, Movavi Video Converter Personal supports 3gpp file conversion as a source file type.||No||No||No||No||No||No||No|
|Yes, Movavi Video Converter Personal supports m4v 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 3gpp to m4v. 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.
Apple macOS / Mac OS X software - convert 3gpp to m4v on OS X
A fully-featured video converter for Mac