Quick answer: Tap Video, choose one from your photo library, and Ringtonius reads its soundtrack and shows the waveform. Select up to 30 seconds, preview, and save. The video itself is never changed or uploaded.
Good for
- The chorus from a concert you filmed
- A child’s laugh, a first word, a birthday song
- A pet that barks on cue
- Your band’s rehearsal
How it compares with doing it yourself
Without an app, you’d extract the audio with a Shortcut, then still need to trim it to 30 seconds before iOS will accept it. The step-by-step version is in how to make a ringtone from a video.