Problem with MIDI-protocol

[Niels Meijer]

Hi everybody,
I have some troubles with the well-known MIDI-protocol. I am trying to make some kind of program that is able to generically generate .midi music. It is not that complicated yet, so do not bother with it, in fact I am just running tests right now. I have this problem when I try to play a self generated MIDI-file with only one note. I was able to copy a existing midi in code (rdbuf()), so it is not my compiler's fault (Dev-C++ 4.9.9.2). I would rather not work with MIDI-libraries so as to only use my own code.
After some hard work on the Internet i finally managed to get the information I needed about MIDI on byte level. I made the midi with fstream and afterwards I wrote a few lines C++ to test if I could correctly apply my newly aquired knowledge. This is the program:

#include <fstream>
int main()
{
  std::ifstream MIDI("MIDI.mid");      //my created sequence (does not work)
  std::ofstream test("txt.txt");       //(I like palindromes)
  test<<std::hex;
  while(!MIDI.fail())
  {
    test<<MIDI.get()<<'\n';
  }

in file txt.txt:

4d
54
68
64
0
0
0
6
0
0
0
1
0
60
4d
54\72
6b
0
0
0
b
1
91
3c
f
66
81
3c
f
ff
2f
0
ffffffff

I started with the header chunk,
then a track chunk,
a note on and
a note off event,
and a end-of-track meta-event.
I have no idea where the large number at the end comes from, is it the cause of all the trouble? When i open MIDI.mid with Notepad, the number 0xffffffff is not represented in Unicode-character, so I cannot get it out of the file. I guess it is just a glitch. The problem occurs when I try to play the file. Windows Media Player starts complaining about insufficient memory so I guess I forgot some kind of EOF event. I also tried Synthesia, becuase I know Windows long enough, but it also refuses to play my file... For the interested, my knowledge originates form this lovely tutorial:
http://www.sonicspot.com/guide/midifiles.html
if you see the error, PLEASE contact me. C++ is my hobby, I learned C++ from a book, so I do not have a teacher to answer my questions. You people are my only hope...

Atleast thanks for reading!

Kind regards,
Niels Meijer

[helios]

get() returns -1 when the stream reaches the EOF. fail() doesn't check if the stream has reached the EOF. Check good(), instead.

Windows Media Player starts complaining about insufficient memory so I guess I forgot some kind of EOF event. I also tried Synthesia, becuase I know Windows long enough, but it also refuses to play my file

Well, my first question would be: when you generated the file, did you open the stream as text or as binary?

[Niels Meijer]

Wow, I didn't expect such a fast answer! I took your advice and to make a long story short here is the complete sourcecode of my program:

#include <iostream>
#include <fstream>
#include <iomanip>
//#define show
#define write
int main()
{
#ifdef show
  std::ifstream MIDI("MIDI.mid");
  std::ofstream test("txt.txt");
  test<<std::hex;
  while(MIDI.good())
  {
    test<<MIDI.get()<<'\n';
  }
  MIDI.close();
  test.close();
#endif
#ifdef write
  std::ofstream MIDI("MIDI.mid",std::ios::binary);
  MIDI.put('M');
  MIDI.put('T');
  MIDI.put('h');
  MIDI.put('d');
  MIDI.put('\x0');
  MIDI.put('\x0');
  MIDI.put('\x0');
  MIDI.put('\x6');
  MIDI.put('\x0');
  MIDI.put('\x0');
  MIDI.put('\x0');
  MIDI.put('\x1');
  MIDI.put('\x0');
  MIDI.put('\x60');
  MIDI.put('M');
  MIDI.put('T');
  MIDI.put('r');
  MIDI.put('k');
  MIDI.put('\x0');
  MIDI.put('\x0');
  MIDI.put('\x0');
  MIDI.put('\xB');
  MIDI.put('\x1');
  MIDI.put('\x91');
  MIDI.put('\x3C');
  MIDI.put('\xF');
  MIDI.put('\x66');
  MIDI.put('\x81');
  MIDI.put('\x3C');
  MIDI.put('\xF');
  MIDI.put('\xFF');
  MIDI.put('\x2F');
  MIDI.put('\x0');
  MIDI.close();
#endif
  std::cin.get();
  return 0;
}

MIDI.mid remains unplayable so I guess the fault lies in my MIDI-syntax.
After uncommenting the forth line I placed '//' before line 5. This is the content of txt.txt:

4d
54
68
64
0
0
0
6
0
0
0
1
0
60
4d
54
72
6b
0
0
0
b
1
91
3c
f
66
81
3c
f
ff
2f
0
ffffffff

Where in the world does 0xffffffff come from? Did I apply good() correctly?
Although I still can't play MIDI.mid, nevertheless thanks for your fast answer!

[helios]

I guess get() only sets the EOF flag if it's called while the stream is at the EOF, and not if it returns while at the EOF. I swear, the C I/O semantics must have been designed by an inhabitant of the Backwards Dimension.

while(1){
    char c=MIDI.get();
    if (!MIDI.good())
        break;
    test<<c<<'\n';
}

Personally, unless I have reasons not to (memory constraints, for example), I just open everything as binary and load entire files to memory. Saves me the trouble of dealing with this backwards BS, and it's more efficient.

[Niels Meijer]

Ah! the number at the end has disappeared! I only had to use an int instead of a char, because char would put ASCII graphs instead of hexadecimal numbers in txt.txt. Thanks again! And I agree about the semantics designers.

Ok, so now my C++ code is fine, but does anyone know what is wrong with the MIDI syntax? I still can't play the file...

The MIDI protocol is so simple, and yet capable of fustrating newbies like me this much!