While I have not used it for this, VLC Player can convert either from an import or a video stream to a variety of other formats, including MP3/4 and H.264; all common video formats.
On a Mac since 1984. Currently: 24" M1 iMac, M2 Pro Mac mini with 27" BenQ monitor, M2 Macbook Air, MacOS 14.x; iPhones, iPods (yes, still) and iPads.
