A method and apparatus for performing file-level restoration from a block-based backup file stored on a sequential storage device is described. In one embodiment, a method of processing a backup file to perform file-level restoration from a sequential storage device comprises generating extent information, wherein the extent information pertains to at least one file system object associated with a backup file, wherein the backup file is to be stored on a sequential storage device, wherein the backup file is block-based and processing a backup catalog, wherein the backup catalog indicates locations of various portions of the extent information and is used to restore a file system object.