Beta SP is a professional tape format developed by Sony. It replaced the original "Betacam" format from the early 1980's, and was the industry standard in portable ENG and EFP for many years. It is currently being superceded by formats such as Beta SX.
Note: These Beta formats should not be confused with "Betamax", the failed consumer format. Although they are closely related, and Betamax tapes can be used with Beta SP equipment, their technical specs are very different.