MIDI file generator - work in progress

[sash]

Ubuntu Linux 18.04, 64 bit.

Random seed: 1562018

[finlazarus]

Hi sash!

Sounds exactly the same as mine mid. Do you have AMD or Intel processor in your PC?

[sash]

Code: [Select]

OS: Ubuntu 18.04 bionic
Kernel: x86_64 Linux 4.15.0-42-generic
CPU: AMD FX-6300 Six-Core @ 6x 3.5GHz
GPU: GeForce GTX 1060 3GB
RAM: 2081MiB / 7941MiB


[finlazarus]

Hi there! Added ComboBox for choosing the tempo for the generated MIDI file. Also the default setup is different. All  my PCs have AMD processor and I'm still curious to know if the Pentium generated sequence differs from the AMD one. Does anyone there have a Pentium machine? Could you try this code and send the MIDI file here? I really would like to know if there is a difference 

[sstvmaster]

Hi,

here Win7 32bit, Pentium T4500, L2.0.6 32bit.

It is different.

[finlazarus]

Thanks sstvmaster!
It's different indeed! Good to know this. A nice piece of (Pentium) music though . Interesting start in the melody and kinda nice melodic curves in the middle.

[metis]

@finlazarus

I have no Idea about MIDI-Programming - I only found some Code in my CodeArchive, that might be helpful for You:

i was unable to find pascal headers for libportmidi

-> see attached 'PortMidi.7z' (= downloaded from 'Breakout Box' some Years ago)

'TMidiInput' and 'TMidiOutput':
-> see attached 'midi.7z' (= downloaded from 'Breakout Box' some Years ago)

At the moment I'm interest in generating random kind of midi music

So this should be the most interesting for You: 'Ramugen v2' (= Random Music Generator) by Greg Fox.
-> see attached 'Ramugen.7z'
(I had to strip all compiled EXE-Files, because of the Limitation of the Attachment to max. 250KB). 

Just keep on going - Creating something on Your own is always Fun. 

[jelston]

G'Day Guys,
I have played around with the pl_win_midi and found a couple of problems namely a memory leak in a couple of components and an error in saving a MIDI file. The changes I made are here:

In file cmpMidiInput.pas
   
destructor TMidiInput.Destroy;
var
  idx : TPortRange;
  i : Integer;
begin
  for idx := Low (TPortRange) to High (TPortRange) do
    ClosePort (idx);

  while fSysexHeaders.Count > 0 do
    TidySysexBuffers;
  fSysexHeaders.free;   //     now no memory leak

  SetRecording (False, Nil);

  for i := 0 to fTakes.Count - 1 do
    TObject (fTakes ).Free;
  fTakes.Free;

  if assigned(fRecordBuffer) then fRecordBuffer.free;
  if assigned(fMidiEchoPort) then fMidiEchoPort.Free;
  inherited;
end;

------------------------------------------------------
Add to cmpMidiOutput.pas
destructor TMidiOutputPort.Destroy;
begin
  Active := False;
  WaitForSysex;
  fSysexHeaders.Free; //  avoid memory leak
 
  inherited
end;

//-------------------------------------
This fixes a problem when saving a MIDI File at runtime
in cmpMidiData.pas
Change NoTracks property to word type
 
 
function  GetNoTracks : word;       
property NoTracks : Word read GetNoTracks;
function TMidiData.GetNoTracks: word;

Sample Code to creatre a MIDI file at runtime
var
  mf:TMIDIData;
  eD:TEventData;   
begin
   mf:= TMIDIData.create(self);
   mf.AddNewTrack(0);
  ed.status := $90; ed.b2 := 60; ed.b3:= 100; // note on
    m.Tracks[0].InsertEvent(0,eD,0);

    ed.status := $80; ed.b2 := 60; ed.b3:= 0;  // note off
    m.Tracks[0].InsertEvent(180,eD,0);         
 
   mf.FileName:='test.mid';
   mf.Save;
   
   mf.free;
end;       
   

[avra]

G'Day Guys,
I have played around with the pl_win_midi and found a couple of problems namely a memory leak in a couple of components and an error in saving a MIDI file.

The origin of that package is CodeTyphon fork of Lazarus. You should report bug fixes for CodeTyphon packages in their forum: https://www.pilotlogic.com/sitejoom/index.php/forum.html

[bycyclepost]

hi group
im new here and have taken a couple years away from coding , i enjoy midi and auto generating midi files ..is the author of this topic still active here , id be interested to modify and add to the 2 trk source ,,,
b.p.

[germona]

Yes, this code works fine with my Lazarus IDE v3.4 on Manjaro Linux.
I am also looking for a lazarus program that can do the reverse, so reading a midi file and show in a form or terminal the start of the notes, the duration, and the velocity.
Would that also be possible, or do you know somebody that wrote someting like that?
Thanks
Jean from Belgium.

[finlazarus]

... id be interested to modify and add to the 2 trk source ,,,
b.p.

Hi bycyclepost.
Of course, you can develop this - after all rather simple - code further. If you share an application you developed based on this code, it would be nice to give some credit to the author of the original code.

[finlazarus]

Yes, this code works fine with my Lazarus IDE v3.4 on Manjaro Linux.
I am also looking for a lazarus program that can do the reverse, so reading a midi file and show in a form or terminal the start of the notes, the duration, and the velocity.
Would that also be possible, or do you know somebody that wrote someting like that?

Thanks for your feedback germona! Nice to hear that the code also works on Linux.

"I am also looking for a lazarus program that can do the reverse, so reading a midi file and show in a form or terminal the start of the notes, the duration, and the velocity."

We are talking about 'MIDI parsing' here I guess.
In other words, how to use Pascal code to extract the musical information from a MIDI file that you want to use for a specific purpose. Reading information from a MIDI file is a much more complex challenge than the fairly simple MIDI file generation code I presented. Above all, it's about what you really want to do, i.e. for what purpose you want to read MIDI information from a MIDI file. Just to list the notes, the duration, and the velocity or develop something more advanced?

MIDI programming is really interesting and there are many different libraries for Pascal as well. However, it is more educational to learn how to manage a MIDI file at a very low level and get to know the structure of a MIDI file from the very start. It may be a long but interesting road.

To read a MIDI file by coding, you need the knowledge about at least the following:
How to handle and read computer file on a byte and bit level. The hexadecimal system. MIDI File Structure overall: Chunk Structure,  MIDI Events (Note on/Note off, running status etc.), Meta Events (key signature, time signature, tempo value etc.), Delta Time, Variable-Length Quantity (VLQ) values and so on.

Coding a MIDI parser from scratch can be a great learning experience, but it takes a lot of effort. After you know the basics, it's easier to get familiar with different code libraries.
There are various tutorials on the Internet that are sometimes hard to find. In any case, it is worth starting from the following site:
https://midi.org/standard-midi-files-specification

I'm always looking for good tutorial sites on the internet my self too and would be happy to receive tips.