XMF is a tree-based

Tree (data structure)

In computer science, a tree is a widely-used data structure that emulates a hierarchical tree structure with a set of linked nodes.Mathematically, it is an ordered directed tree, more specifically an arborescence: an acyclic connected graph where each node has zero or more children nodes and at...

 digital container format used to bundle music-oriented content, such as a MIDI file and optionally the sounds it uses, liner notes or other content grouped by language-codes.

The first defined use of the XMF was to allow the bundling of a musical performance with the musical sounds (optional) it uses. For instance, a MIDI file could be stored together with a Downloadable Sounds

DLS format

DLS is a family of standardized file formats for digital musical instrument sound banks . The DLS standards also include detailed specifications for how MIDI protocol-controlled music synthesizers should render the instruments in a DLS file...

 file, and both files would travel together inside one XMF file. This specific use of an XMF file is referred to as XMF File Type 0 (streaming) or XMF File Type 1 (non-streaming), depending on whether the type of the MIDI file is 0 or 1, respectively.

There are currently five XMF File Types defined. The latest of which is XMF File Type 4 (counted from zero) and is called Interactive XMF (iXMF).

The specifications for the XMF was first published in 2001 by the MMA

MIDI Manufacturers Association

The MIDI Manufacturers Association is an organization where companies work together to create the standards that assure compatibility among MIDI products. The MMA is a U.S. organization established in 1985 by the original developers of the MIDI 1.0 Specification in 1983. Since 1985 the MMA has...

.

Features

• Resources can be referenced internally (in the XMF file) or referenced externally using a URI
  Úri
  Úriis a village and commune in the comitatus of Pest in Hungary....
  
  .
• Resources can be country- and language-coded so that text could be shown in the right language depending on context.
• Resources can be compressed using ZLIB
  Zlib
  zlib is a software library used for data compression. zlib was written by Jean-Loup Gailly and Mark Adler and is an abstraction of the DEFLATE compression algorithm used in their gzip file compression program. Zlib is also a crucial component of many software platforms including Linux, Mac OS X,...
  
  .
• Size information is stored using variable-length quantities
  Variable-length quantity
  A variable-length quantity is a universal code that uses an arbitrary number of binary octets to represent an infinitely large integer. It was defined for use in the standard MIDI file format to save additional space for a resource constrained system, and is also used in the later Extensible...
  
  , ensuring that the format can support an infinite number, while at the same time saving storage space.

External links

• MIDI Manufacturers Association
  MIDI Manufacturers Association
  The MIDI Manufacturers Association is an organization where companies work together to create the standards that assure compatibility among MIDI products. The MMA is a U.S. organization established in 1985 by the original developers of the MIDI 1.0 Specification in 1983. Since 1985 the MMA has...
  
  (MMA)
• XMF Overview
• XMF Working Group of the MMA
• Mobile XMF of the MMA