How to make a ringtone from mp4 video on Android?

Can I make a ringtone on my Android phone from mp4 video file ? If yes, how can I do it ? What app should I use to separate a sound from video ?

You can use MP3 file as a ringtone, but not the MP4 video file.

There is actually the way how to use the audio from your MP4 file as a ringtone. You have to extract audio from MP4 file, using an app and save the audio as MP3 file.

Android itself doesn't have an app for audio extraction from video files. You have to download some third party application to do this.