Riffstation
Riffstation is a desktop application for Mac and Windows computers. Load any MP3 and Riffstation will automatically detect the chords and sync the chord diagrams with the music. You can also slow down the audio, change the pitch, isolate or mute guitar parts, loop specific sections and even sync a metronome. Until May 2018, there used to be a free web version that worked on YouTube videos, an iOS version, and the desktop version was paid for ($34.99). The iOS and web versions are no longer available, and the desktop version is now free.
