The MVT package ("MIDI Via Text") allows standard MIDI files to be edited using a simple text format derived from the one used by MIDICSV that looks like this:
start-file 4 4
start-track "Brother Jake"
1:1:0 tempo 110.00
1:1:0 note 1 C5 64 480
1:2:0 note 1 D5 64 480
1:3:0 note 1 E5 64 480
1:4:0 note 1 C5 64 480
end-track
end-file
Also provided is a special Emacs mode for editing MVT files. There are commands for hiding, showing, selecting, and modifying groups of MIDI events interactively. There are also facilities for playing MVT files over MIDI, and for playing and recording MIDI notes from within Emacs, using an auxiliary Racket Scheme program based on SPUR but here using the PortMidi interface.
Download MVT version 1: archive README Errata