smftoxml takes a standard midifile as input and outputs an exact representation of it in XML form (its own format, not any standard).

xmltosmf turns the output of the above back into a midifile. As the XML is easy to read and edit, you can make changes (like removing Sequitur's massive metaevents when you no longer need them!) before recreating the midifile.

tempomap is the app that has finally solved an Amiga-Era problem for me! Back then I recorded (from live input) a multitrack composition without bothering to conform to the sequencer's sense of 'measure'. Ever since I've been trying to find a way to adjust it so that  despite its uneven tempo  it will have sensible bar markings in a sequencer. tempomap has finally achieved this! You add a click-track to match the actual beats in the recording, and it adjusts timing and adds tempo events so that, although the file sounds the same, the bar divisions now line up with the clicks.