Midi events delta time

    https://sites.uci.edu/camp2014/2014/05/19/timing-in-midi-files/
    http://www.music.mcgill.ca/~ich/classes/mumt306/StandardMIDIfileformat.html#BM2_3

    - Delta-time is in some fraction of a beat (or a second, for recording a track with SMPTE times), as specified in the header chunk.
    - nardis header track:
        Format: 1
        tracks: 10
        division : 480
            The third word, <division>, specifies the meaning of the delta-times.
            It has two formats, one for metrical time, and one for time-code-based time:

            bit 15	bits 14 thru 8	                bits 7 thru 0
            ======|===============================|==============
            0	  |     ticks per quarter-note
            1	  |     negative SMPTE format	  |   ticks per frame

            If bit 15 of <division> is zero, the bits 14 thru 0 represent the number of delta time "ticks" which make up a quarter-note.
            For instance, if division is 96, then a time interval of an eighth-note between two events in the file would be 48.

            nardis division == 480 => bit 15 is zero, so we have 480 ticks per quarter note.
            default tempo is 120, if not specified by a meta event
            default time signature is 4/4 if not specified by a meta event
            nardis has 4/4 time signature and tempo of 300000 microseconds per quarter note


            MIDI header track gives division, which is PPQ (parts per quarter or ticks per quarter note). Nardis = 480 => delta time of 480 means a quarter note.
            But how long is a quarter note? that is given by the tempo.



PITCH bending
    https://sites.uci.edu/camp2014/2014/04/30/managing-midi-pitchbend-messages/
    - we get a 14bit value, [0..16383]
    - map this to [-1..1], meaning that 16383/2 means no bend
    - the float is the relative amount of bending, we should multiply it by a synth setting which says what is the bending range (+/- 2 semitones for example)