This document defines the data structure of the Material Exchange Format (MXF) for the interchange of audio-visual material. It defines the data structure for network transport and may be used on storage media. This document does not define internal storage formats for MXF compliant devices. - The document defines all the components of the MXF file specification including all those in the File Header, File Body and File Footer. It defines the application of Partitions in the file that provide valuable features such as the ability for an MXF file to serve many application requirements and recovery of partially received files. The document also defines key features of the file structure including the Partition Packs, the Structural Metadata, the Primer Pack, the Random Index Pack and Index Tables. - The document does not define either the Essence Container or the Descriptive Metadata. Instead, it defines the requirements for these components to be added as a plug-in to an MXF file.