What library do you use when you change the .mov to mp4 in React(Typescript)?

I’m student studying web programming.
I have a question while working on the project.

In our project, users can put images or videos.
By the way, videos are uploaded well on Android devices, but not on iPhones.
I think the Android video extension and the iPhone video extension are different.

How do I convert .mov to mp4 when using React? Do you have a library that you commonly use?
And this conversion is the usual way?

Thank you for reading it!!