Parsing a MIDI file for Note On only

Question

I've been trying to figure out the mystical realm of MIDI parsing, and I'm having no luck. All I'm trying to do is get the note value (`60` = C4, `72` = C5, etc), in order of when they occur. My code is as follows. All it does is very simply open a file as a byte array and read everything out as hex: ``` byte[] MIDI = File.ReadAllBytes("TestMIDI.mid"); foreach (var element in MIDI) { string b = Convert.ToString(element,16); Debug.WriteLine(b); } ``` All TestMIDI.mid contains is one note on C5. Here's a hex dump of it. Using this info, I'm trying to find the simple hex value for Note On (`0x9`, or just `9` in the dump), but there aren't any. I can find a few `72`'s, but there are 3, which doesn't make any sense to me (note on, note off, then what?). This is my first attempt at parsing MIDI as a file and using hex dumps (are they even called that?), so I'm sorry if I'm heading in the complete wrong direction. All I need is to get the note that plays, and in what order. I don't need timi…

Accepted Answer

Accepted answer is not a solution for the problem. It will not work in common case. I'll provide several cases where this code either will not work or will fail. Order of these cases corresponds their probability - most probable cases go first.

- False positives. MIDI files contain a lot of data structures where you can find a byte with the value 144. And these structures are not Note On events. For real MIDI files you'll get bunch of "notes" that are not notes but random values within the file.

- Channels other than 0. Most of the modern MIDI files contain several track chunks. Each one holds events for the specific MIDI channel (from 0 to 15). 144 (or 90 in hex) represents a Note On event for the channel 0. So you are going to miss a lot of Note On events for other channels.

- Running status. MIDI files actively use concept of running status. This technique allows don't store status bytes of consecutive events of the same type. It means that status byte 144 can be written only once for the first Note On event and you will not find it further in the file.

- 144 is the last byte in a file. MIDI file can end with this value. For example if a custom chunk is the last chunk in the file or track chunk doesn't end with End of Track event (which is corruption according to MIDI file specification but possible scenario in real world). In this case you' ll get IndexOutOfRangeException on MIDI[i+1].

Thus, you should never search for specific value to find some semantic data structure in a MIDI file. You must use one of the .NET libraries available on the Internet. For example, with the DryWetMIDI you can use this code:

```
IEnumerable<Note> notes = MidiFile.Read(filePath)
                                  .GetNotes();
```

Parsing a MIDI file for Note On only

Solution

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