As mentioned by earlier correspondents, the music industry generally regarded Bohemian Rhapsody as the first formal pop video. It was made in three and a half hours using a prismatic lens - because they couldn't perform the song live on Top Of The Pops.
Certainly that was the inspiration for MTV, the pop video channel.
But other musicians also lay claim to starting the trend, not least The Beatles who claim that their 'promos'
for Paperback Writer and Rain, made in 1966, were the beginnings.