Material Exchange Format

Material eXchange Format (MXF) is a container format for professional digital video and audio media defined by a set of SMPTE standards.

A brief summary of MXF

MXF is a "container" or "wrapper" format which supports a number of different streams of coded "essence", encoded with any of a variety of codecs, together with a metadata wrapper which describes the material contained within the MXF file.

MXF has been designed to address a number of problems with non-professional formats. MXF has full timecode and metadata support, and is intended as a platform-agnostic stable standard for future professional video and audio applications.

MXF was developed to carry a subset of the Advanced Authoring Format (AAF) data model, under a policy known as the Zero Divergence Directive (ZDD). This enables MXF/AAF workflows between non-linear editing (NLE) systems using AAF and cameras, servers, and other devices using MXF.

MXF in use

MXF is in the process of evolving from standard to deployment. The breadth of the standard can lead to interoperability problems as vendors implement different parts of the standard.

Currently, MXF is fairly effective at the interchange of D10 (IMX) material, mainly because of the success of the Sony eVTR and Sony's eVTR RDD to SMPTE. Workflows combining the eVTR, Avid NLE systems, and broadcast servers using MXF in coordination with AAF are now possible.

Long-GOP MPEG-2 material interchange between video servers is improving, especially as broadcasters develop application specifications they expect their vendors to implement.

As of Autumn 2005, there were major interoperability problems with MXF in broadcast post-production use. The two data-recording camera systems which produce MXF, Sony's XDCAM and Panasonic's DVCPRO P2, produce files which are mutually incompatible due to opaque subformat options obscured behind the MXF file extension. Without advanced tools, it is impossible to distinguish these incompatible formats.

Additionally, many MXF systems produce split-file A/V (that is, the video and audio stored in separate files), and use a file naming convention which relies on randomly generated filenames to link them. Not only does this exacerbate the issue of knowing exactly what is in an MXF file without specialized tools, but it breaks the functionality of standard desktop computer techniques which are generally used to manipulate data on a level as fundamental as moving, copying, renaming, and deleting. Using a randomly generated filename is uninformative to the user, but changing the name breaks the loose database structure between files.

MXF is also used as the packaging format for Dolby Digital Cinema, as shown in their demo.

Panasonic's P2 MXF is supported by Avid, Autodesk Smoke, Adobe After Effects, Adobe Premiere Pro, MXF4QT for Final Cut Pro, P2Soft

The file extension for MXF files is ".mxf". The Macintosh File Type Code registered with Apple for MXF files is "mxf " (note the trailing space) .

CinemaDNG (intended by Adobe and others to be an open file format for digital cinema files) exploits MXF as one of its options for holding a sequence of raw video images. (The other option is to store a sequence of DNG files in a specified directory).

Tools

NLE and MXF enablers

There is an increasing number of professional NLE's that can work with MXF files natively including [[Avid], [Adobe Premiere Pro|Adobe Premiere Pro 3.1 or above]], Sony Vegas, and GrassValley Edius. Latest versions of Avid editing products store media in MXF Op-Atom and import/export MXF Op1a or using Toboggan MediaTransfer that supports any kind of MXF flavour. Native MXF access in Apple's Final Cut Pro and other Mac OS X applications can be achieved by using the MXF4QT Import component from Hamburg Pro Audio.

MXF converters

XFConverter enables users to convert wrapper formats (such as MXF, Quicktime, GXF, AVI, etc.) without having to modify their video/audio essences.

SDKs

There are a number of MXF SDKs available that enable manufacturers and integrators to reduce their time to market by allowing them to rapidly make the most of MXF technology such as MXFTk, MXFLib and MXF::SDK.

MXF analysers

• IRT MXF Analyser is an analysing tool to validate the standard compliance of MXF files and to export the complete file structure as XML.
• MXF Info is a comprehensive MXF analyzer application to read the entire internal KLV structure of MXF files including Header, Body and Footer Partitions.

MXF readers

XFReader is a simple Player that runs under Windows and enables users to play back all MXF files on a display unit or an SDI Video Screen. It is based on the MXFTk Reader Direct Show filter which allows MXF files to be managed in Windows Media Player.

MXF Desktop is a free software application from AmberFin that adds MXF (Material eXchange Format) awareness to PCs running Windows XP or Windows 2000 operating systems. It enables: Microsoft Windows Media Player to play MXF files; easy viewing of key metadata within an MXF file via the right-click Properties command in Windows Explorer; WAV, MPEG and DV formats to be "wrapped" as essence into an MXF file.

MXF archivers and servers

Ingex is a an open-source (GPL) suite of software for the digital capture of audio and video data, developed and heavily used by the BBC.^[1] SDI capture is supported, as well as real-time transcoding (with MXF).^[1] Portions of the suite also act as a network file server for media files, as well as archiving to LTO-3 data tape.^[1]

The MXF Standards

• Base Documents
  • SMPTE 377M: The MXF File Format Specification (the overall master document)
  • SMPTE EG41: MXF Engineering Guide (A guide explaining how to use MXF)
  • SMPTE EG42: MXF Descriptive Metadata (A guide explaining how to use descriptive metadata in MXF)
• Operational Patterns
  • SMPTE 390M: OP-Atom (a very simple and highly constrained layout for simple MXF files)
  • SMPTE 378M: OP-1a (the layout options for a minimal simple MXF file)
  • SMPTE 391M: OP-1b
  • SMPTE 392M: OP-2a
  • SMPTE 393M: OP-2b
  • SMPTE 407M: OP-3a, OP-3b
  • SMPTE 408M: OP-1c, OP-2c, OP-3c
• Generic Containers
  • SMPTE 379M: Generic Container (the way that essence is stored in MXF files)
  • SMPTE 381M: GC-MPEG (how to store MPEG essence data in MXF using the Generic Container)
  • SMPTE 383M: GC-DV (how to store DV essence data in MXF using the Generic Container)
  • SMPTE 385M: GC-CP (how to store SDTI-CP essence data in MXF using the Generic Container)
  • SMPTE 386M: GC-D10 (how to store SMPTE D10 essence data in MXF using the Generic Container)
  • SMPTE 387M: GC-D11 (how to store SMPTE D11 essence data in MXF using the Generic Container)
  • SMPTE 382M: GC-AESBWF (how to store AES/EBU and Broadcast Wave audio essence data in MXF using the Generic Container)
  • SMPTE 384M: GC-UP (how to store Uncompressed Picture essence data in MXF using the Generic Container)
  • SMPTE 388M: GC-AA (how to store A-law coded audio essence data in MXF using the Generic Container)
  • SMPTE 389M: Generic Container Reverse Play System Element
  • SMPTE 394M: System Item Scheme-1 for Generic Container
  • SMPTE 405M: Elements and Individual Data Items for the GC SI Scheme 1
• Metadata, Dictionaries and Registries
  • SMPTE 380M: DMS1 (a standard set of descriptive metadata to use with MXF files)
  • SMPTE 436M: MXF Mappings for VBI Lines and Ancillary Data Packets
  • SMPTE RP210: SMPTE Metadata Dictionary (the latest version is available here: http://www.smpte-ra.org/mdd/index.html )
  • SMPTE RP224: Registry of SMPTE Universal Labels

Availability of Standards

SMPTE's top standards page has information, for the ordering of CD-ROMs, which would hold formal copy of the SMPTE standards. Judging by SMPTE's index, all of the standards, referenced above, would be contained on those CD-ROMs, as available from SMPTE.

See also

• AAF, Advanced Authoring Format
• BWF, Broadcast Wave Format

References

External links

• http://www.craystone.co.uk MXF Aware tape units from Craystone of Bolton
• http://www.opencubetech.com/pub/rubrique.php?id=13/ Commercial MXF solutions
• http://www.mog-solutions.com/ MXF solutions for professionals
• http://www.amwa.tv/ Advance Media Workflow Association
• http://mxf.info/ MXF Implementation
• http://www.irt.de/mxf/ MXF Test Center
• http://www.freemxf.org/ A multi-platform open source C++ library for reading and writing MXF files
• RFC 4539 (MIME type registration)
• US Library of Congress Digital Preservation Program: MXF Format Description Properties
• The Ingex Project
• MXF File Converter
• MXF File Converter for Mac
• http://mxf4mac.com/ Native and transparent MXF solutions for the Mac
• http://www.merging.com/vcube MXF solutions for broadcasters