MusicTrans is described as 'Without touching any control, MusicTrans will give you a graphical view of what notes are being played. An intermediate player can easily get the basic chords just by looking at the screen, and that’s just the tip of the iceberg!' and is an app in the Audio & Music category. There are more than 10 alternatives to MusicTrans for a variety of platforms, including Mac, Windows, iPhone, iPad and Linux. The best alternative is Sonic Visualiser, which is both free and Open Source. Other great apps like MusicTrans are Chordify (Freemium), Amazing Slow Downer (Freemium), Transcribe! (Paid) and AudioScrub (Paid).
Change the speed of the music - from 20% (one fifth speed) to 200% (double speed) without changing the pitch. Wrong key? Change the pitch in semi-tones - at full or changed speed. Out of tune? Adjust the pitch in cents (100ths of a semi-tone) to suit your instrument.