Not sure if OP is accurate here? Please correct me if I’m wrong.
If you export from QuickTime using the Apple Devices preset on export, that is an MP4 profile. Simply export and then rename the file from .m4v to .mp4. I’ve done this countless number of times.
If you export from QuickTime using the Apple Devices preset on export, that is an MP4 profile. Simply export and then rename the file from .m4v to .mp4. I’ve done this countless number of times.