I have some rather large mp4s produced by my phone. They aren't very long, so they're probably not very compressed. What's an example of using a command line Linux tool to transcode one of these to either h.264 or vp8 or vp9, and how can I play with the quality/compression trade-off?
I know it can be done with vlc. I get lost in the documentation though, and I haven't found clear examples in my web searches.