Material Exchange Format (MXF) is an open wrapper format developed by the Society of Motion Picture and Television Engineers. It supports a number of different bitstreams encoded with any of a variety of codecs, together with a metadata wrapper that describes the material contained within the MXF file. The wrapper is relatively transparent although the structure of an MXF file can be complex. Since invention of this format, there is an ever-increasing interest and adoption of MXF. It is emerging as a standard for professional digital video and audio media. For example, the Library of Congress National Audio-Visual Conservation Center produces a form of MXF as archival masters as they reformat their older videotapes.