It looks like the version of ffmpeg that is included in the Mac Installer is missing the amr_nb encoder for creating 3gp files. It looks like the installer is getting ffmpeg from Homebrew. The newest version of ffmpeg (https://formulae.brew.sh/formula/ffmpeg) include amr_nb using opencore-amr library).
It looks like the version of ffmpeg that is included in the Mac Installer is missing the amr_nb encoder for creating 3gp files. It looks like the installer is getting ffmpeg from Homebrew. The newest version of ffmpeg (https://formulae.brew.sh/formula/ffmpeg) include amr_nb using opencore-amr library).