What is MIDI?
Friday, March 23, 2007
By Stephane Brault
MIDI Karaoke File (.KAR) Format
MIDI-Karaoke (which uses the ".kar" file extension) files are an "unofficial" extension of MIDI files, used to add synchronized lyrics to standard MIDI files. SMF players play the music as they would a .mid file but do not display these lyrics unless they have specific support for .kar messages. These often display the lyrics synchronized with the music in "follow-the-bouncing-ball" fashion, essentially turning any PC into a karaoke machine.
MIDI-Karaoke file formats are not maintained by any standardization body.
XMF File Formats
The MMA has also defined (and AMEI has approved) a new family of file formats, XMF (eXtensible Music File), some of which package SMF chunks with instrument data in DLS format (Downloadable Sounds, also an MMA/AMEI specification), to much the same effect as the MOD file format. The XMF container is a binary format (not XML-based, although the file extensions are similar).
RMI File Format
On Microsoft Windows, the system itself uses RIFF-based MIDI files with the .rmi extension. Note, Standard MIDI Files per se are not RIFF-compliant. An RMI file, however, is basically an SMF wrapped in a RIFF header. If the RIFF header is thrown away, the result should be a regular SMF.
The RMI file format is not maintained by any standardization body.
MIDI usage an applications
Extensions of the MIDI standard
Many extensions of the original official MIDI 1.0 spec have been standardized by MMA/AMEI. Only a few of them are described here; for more comprehensive information, see the MMA web site.