add structure to README

Author: Cornerback24

README.md

@@ -4,7 +4,6 @@ The idea here is to decode midi files into objects that are easy to extract data
 This will probably only work with type one midi files which are organized so that each track contains data for a separate instrument.
 
 (This isn't meant to create or manipulate midi files; it is just to get data from them.)
-Current work in progress is generating note objects from the midi file, with start and stop times.
 
 At this point, this script should be able to take a format one midi file that has one channel per track,
 and create Notes with start and stop times.  To do this, create a MidiData (ex midiData = MidiData("testMidiFile.mid")).  
@@ -17,3 +16,24 @@ field in the range 0 - 127.  trackData.name contains the name of the track, whic
 trackData.events contains the midi events in the track, and each event has a startTime field in milliseconds. Midi events are defined in
 MidiEvents.py.
 TrackData, MidiData, and Note may need to imported.
+
+Structure (only intended output values listed):
+MidiData: contains all data for a midi file (created by calling MidiData("midi_file.mid")
+          where "midi_file.mid" is the path to the midi file)
+    getNumTracks(): number of tracks in the midi file
+    tracks: list of TrackData (one TrackData for each track in the file)
+    getTrack(index): returns the TrackData with the given index (ex. data.getTrack(1) to get the data for the second track)
+
+TrackData: contains all the data for a single track
+    notes: list of Note (one Note for each note in the track)
+    channel: channel
+    events: list of MidiEvents that make up the track (see MidiEvents.py for definitions)
+    name: name of the track
+
+Note:
+    pitch: note number
+    startTime: start time in ms
+    endTime: end time in ms
+    velocity: velocity
+    releaseVelocity: release velocity
+    length(): length of the note in ms