What is the easiest way to rip the audio from a video and save it?

I had a situation last night where I felt the need to record someone (not work related) but the video files are huge. I'm trying to upload them to Google drive so I have them in case I need them in the future, but the files are way too big and Google drive can't handle it.

There's really only a couple of minutes of video that are relevant, but there's quite a bit of audio I may need in the future.

Also I really need to do this on my phone - since I can't upload most of them to Google drive, I have no way to get them on my computer.

Yes I've tried Dropbox.

No I'm not using an iPhone so there is no cloud that connects to my computer.

I really just need the audio because my phone was under a blanket most of the time so most of the video is irrelevant.

I apologize if I sound curt or rude but it's a really serious situation so I just wanna make sure I'm not answering questions I already answered. I appreciate everyone's help.

I'm trying a video to mp3 app right now, if it works I'll be deleting this thread