SMAF stands for "Synthetic music Mobile Application Format", and is a multimedia data format invented by the Yamaha Corporation. The SMAF specification defines a format for multimedia files which can be played back on hand-held portable devices. The SMAF file has the virtue that files sizes are small relative to those of comparable formats, such as SMF (standard MIDI).
At present, SMAF is chiefly used for creating ring tones for mobile phones; however, the full specification also defines support for display of text and graphics. Hence, the format has considerable potential for the creation of rich, yet compact, mobile multimedia content.

A variety of software tools are available to content developers: these include converters, authoring tools and voice libraries. Existing sound files in popular file formats-such as .wav or .mid (standard MIDI) files-can easily be converted to SMAF. A SMAF audio file is typically less than two-thirds the size of the equivalent SMF (standard MIDI) file. Hence, SMAF is an ideal medium for economically sharing and distributing audio content.

The Yamaha Corporation manufactures five audio LSIs, the MA-1, MA-2, MA-3, MA-5 and MA-7 that are expressly designed for the purpose of playing back SMAF audio files. These chips are incorporated into many of today's mobile phones. Any device incorporating one of these chips is capable of playing back SMAF audio files.
The MA-1, MA-2, MA-3, MA-5 and MA-7 are capable of simultaneously playing 4, 16, 40, 64, and 128 notes respectively.