In terms of chords and melody, Wedding Etude is more complex than the typical song, having above average scores in Chord Complexity, Melodic Complexity, Chord Progression Novelty and Chord-Bass Melody.
Wedding Etude is written in the key of D♭ Major. According to the Theorytab database, it is the 9th most popular key among Major keys and the 15th most popular among all keys. Major keys, along with minor keys, are a common choice for popular songs. The three most important chords, built off the 1st, 4th and 5th scale degrees are all major chords (D♭ Major, G♭ Major, and A♭ Major). See the D♭ Major Cheat Sheet for popular chords, chord progressions, downloadable midi files and more!