The vid placeholder represents a unique alphanumeric identifier assigned by Oracle Secure Backup when the volume was labeled.
vid
Specifies an identity for a volume. The volume ID usually includes the media family name of the volume, a dash, and a unique volume sequence number. For example, a volume ID in the RMAN-DEFAULT media family could be RMAN-DEFAULT-000002. A vid can contain up to 31 characters, in any combination of alphabetic and numeric characters, but the last 6 characters must be numeric.