The BBC Archive now contains around 15 Petabytes (and growing) of uncompressed files that have been created from videotapes using the BBC R&D Ingex Archive software. The files conform to a custom profi le of the sophisticated media file wrapper standard known as Material eXchange Format (MXF). The details of the custom profi le are fully speci fied by other BBC R&D White Papers but these documents are not suitable for newcomers to MXF. This White Paper provides an overview of the BBC Archive MXF profi le along with a brief introduction to the MXF fundamentals that are required in order to understand it. A diagram of the physical structure of the MXF fi les is presented - this form of visualisation is found to be very helpful in considering new means of processing the files as well as understanding the consequences of di fferent modes of file corruption.