//NOTE: For this example to work you will need to copy 'music.mp3'
//to the media folder at the location where you are running this example.
//The file can be found in your [AGK Install Directory]/Projects/Basic/Examples/Sound/PlayingMusic/media/

Setvirtualresolution(640,480)
ResetTimer()

//Check for required custom font files in media folder
fileok=GetFileExists("music.mp3")
If fileok<>1
    Repeat
        Print ("music.mp3 needs to be in your media folder")
        Sync()
    Until Timer()>5
EndIF

If fileok=1
    music = LoadMusic("music.mp3")
    Repeat
        If GetMusicExists(1)
            Print ("Music File Exists")
        EndIf
        Sync()
    Until Timer()>12
EndIf
End

It should be noted that m4a files, which as of writing this, are free from licensing unlike mp4!
These will work on iOS and Android, but not Windows (not sure about Mac).