midi file parsing, unrecognised event type

Question

I have a problem trying to parse a midi file. I am trying to parse the notes files used by the frets on fire game (it just uses midi files so i don't think this is relevent) if any of you are familiar with it, the problem i am having is a general midi problem. I have a file with a track called guitar part, the hex, as viewed in a hex editor is as follows:

4D 54 72 6B 00 00 1E 74 00 FF 03 0B 50 41 52 54 20 47 55 49 54 41 52 A9 20 90 61 40 9A 20 61 00 83 60 63 40 BC

My program parses this fine as follows:

4D M
54 T
72 R
6B K
00 < --
00 size of
1E track part
74 -- >
00 time of this event
FF event type (this is meta)
03 meta event type
0B length of data
50 "P"
41 "A"
52 "R"
54 "T"
20 " "
47 "G"
55 "U"
49 "I"
54 "T"
41 "A"
52 "R"
A9 time of event (variable length) 10101001
20 time of event (variable length) 00100000
90 event,channel (non-meta) 1001=note on,channel=0000
61 note on has 2 params this is the first
40 this is the second
9A variable time 10011010
20 variable time 00100000

This is where my problem lies, there is no event that has event type 0x6, since 0x61 is 01100001 we have to assume it's non meta, therefore the event type should be 6 (0110) and the channel is (0001) but the midi specification contains no identification for this event.. I've added a few of the bytes after this incase they are somehow relevent but obviously at the moment my program hits the next byte, doesn't recognise the event and bombs out.
61
00
83
60
63
40
BC

If anyone thinks they could shed any light on where my parsing logic has gone wrong i'd be most appreciative, sorry for the formatting, i couldn't think of a better way to illustrate my problem.

I have been using this site: http://www.sonicspot.com/guide/midifiles.html as a reference and it hasn't led me wrong so far. I figured this might be something directly relating to frets on fire but it doesn't seem to be as i downloaded another notes file for the game and that file did not contain this event.

Thanks in advance.

Answer 1

It's called running status. If an event is of the same type as the previous event, the MIDI status byte can be eliminated. So if the first byte after the timing info is < $80, use the previous status. In the case of your $61 byte, the previous status was $90, so it's Note On, channel 0. Which makes sense since the previous event was note number $61 velocity $40. This event is note number $61 velocity 0 (releasing the previously played note). The next event is note number $63 velocity $40.