The Yamaha Mobile Music Sequencer (MMS) app for iPad is a fun tool, but it cannot import MIDI files or new musical phrases. This limits its real-world usefulness. One way to import MIDI is to slave MMS to another sequencer and play MIDI track by track into MMS. If your goal is new phrases for remixing or composition, you then face the laborious task of cutting, pasting and editing new phrases. Overall, this process involves a lot of manual work!

I just finished experimenting with a backdoor method for importing new MIDI-based musical phrases into MMS. See this page for all of the gory details.

MMS phrases are stored in Apple binary property list files (plist) with the “yms2” extension. The Apple plutil tool prints plist file contents and converts a plist file between XML and binary form. The XML provides a way into the guts of a phrase file and lets you change phrase properties or, ta da!, replace the MIDI data with your own MIDI data. The MIDI data in the binary yms2 file is a Standard MIDI File (SMF). The MIDI data must be encoded in base64 text format when working with XML. Fortunately, there are plenty of base64 conversion tools available on the web.

Once you have a new yms2 file in hand, use Apple iCloud or iTunes file sharing to transfer the yms2 file to your iPad and MMS. Be patient, though. Sync’ing is not instantaneous and it may take several minutes for the phrase file to make its way into MMS.

As a test, I converted the main and fill sections of the PSR-S950 “Jazz Funk” style to 60 (!) new MMS phrases in yms2 format. As Lou would say, here’s your sweet taste. The ZIP file decompresses into 60 phrase files with the “yms2” extension. Through iCloud, you’ll need to transfer these files to the mobile documents folder belonging to MMS. When you launch MMS, it will import the new files and update its internal catalog of phrases.