Open Media Framework (Omf)
Open Media Framework (Omf), sometimes called Open Media Framework Interchange (Omfi), is a de facto standard by Avid Technology, Inc. It is a binary format, offering a cross-platform, extensible, and "rich" container capable of holding complex composition information, including effects, as well as media data.
In the early years, Avid made serious efforts to promote Omf through SMPTE, and AES, but, ultimately, it was never standardized. Yet , because of Avid and DigiDesign's continued use of Omf in their systems and their dominant market position, it is still a widely used interchange format.
Partly because of the difficulties encountered in standardizing Omf, Advanced Authoring Format (AAF) and Material eXchange Format (MXF) were born. They are the successors to Omf and inherit much from it. The industry will begin to accept the use of AAF and MXF as they are deployed by Avid and other industry manufacturers in new applications.
But Omf may never die. There is a huge installed base of Omf and it is a central component of many work-flows. Avid products continue to support it, and, while AAF and MXF are said supersede it, like the old EDL format which is still a workhorse, Omf will be used for years to come.
The Future of Edit Data Exchange - Open Media Framework (OMF) and Edit Decision Lists (EDL) - Brooks Harris - March 1997
For more about the history and status of Omf, Ron Franklin has written a good overview for Mix - Workstation File-Format Interchange, Part 1 - Ron Franklin, Mix, Oct 1, 2002