This is what it says on YouTube:

This colour clip was shot silent in 1955 in Oklahoma City while Holly and Elvis Presley were working the two bottom slots on a country package tour headlined by Hank Snow — and apparently represents not only the earliest film footage of Holly but that of Elvis as well (he’s dressed in a neon-bright green shirt and he’s already a physically commanding figure).

Other YouTubers are saying this was shot in Buddy Holly’s high school in Lubbock, Texas, the following year. Whatever the case, you can also catch Carl Perkins, and at :58 seconds in, a really young-looking Johnny Cash.
 

 
(via Everlasting Blort)