TABLE OF CONTENTS We have talked a lot about metadata, but we have not mentioned what metadata is. The common definition is metadata is data about data. In other words, it is data that defines or describes something about valuable data that is actively managed by some application or person. Metadata is not new it has been with broadcasters and content creators since the early days of audio and television production. Often, the metadata was hidden (e.g., if the videotape cassette was very big, it was probably D-1; if it was very small, it was probably DV). In the file domain, there is no cassette to look at, so applications have to agree on the signaling of the format of the video data so that they can successfully open and process the file.
It is the job of the structural metadata in MXF to describe accurately the essence data and the relationships of all the different essence tracks. The MXF-AAF data model is highly structured. A simplified version of that data model is given in Figure 5.13.
The diagram shows, that parsing an MXF file starts at the preface set, which references identification sets and a content storage set. This then references the packages and EC data sets, which allow all of the details of the logical and physical storage to be resolved. So, what s in a package? The UML-like figure in Figure 5.14 shows the structure of a generic package.
