I remember i saw a version of that 音楽 video with him playing the ギター but now i've revisited the video and i couldn't find him so either i was asleep and dreaming that first time または there are もっと見る than one version to that video :)) i'm gonna look for it and when i'll find it i will post it here.
later edit: say this is what i found. It's actually another song but for the same cause