MIDI strangeness (patch setting and first notes)

sciurius · July 30, 2019, 9:04am

I have a MIDI segment that starts at 027|01|0000. There is a patch setting, also at 027|01|0000, and the first notes also start at 027|01|0000. Times are checked with right-click “Edit…” for the notes and double-click edit for the patch.
When I play it (fluidsynth plugin) the patch setting is not processed at the beginning, but some time later.
Inspecting the MIDI file (in the interchange dir) it shows the first note-ons before the patch is set. Playing this file with e.g. timitidy confirms this.

Did I do something wrong?

x42 · July 30, 2019, 4:29pm

Can you check with “a-MIDI monitor” before the synth plugin? A patch-change should result in two CC messages (bank select CC0, CC32) followed by a program-change.

The ordering of events in the file itself is not relevant (only the timestamp is).

x42 · July 30, 2019, 4:38pm

PS.
Nevermind. it seems to be an issue with Ardour’s event ordering: In case there are multiple events with the same timestamp, Note-on/off events are preferred over all other events.

Now I think it should be changed to prefer CC, PGM (and SysEX) and send Note events last.

The sort-order is defined in Evoral::Sequence::const_iterator::choose_next():

github.com

Ardour/ardour/blob/master/libs/evoral/src/Sequence.cpp#L237-L280


Sequence<Time>::const_iterator::choose_next(Time earliest_t)
{
	_type = NIL;


	// Next earliest note on
	if (_note_iter != _seq->notes().end()) {
		_type      = NOTE_ON;
		earliest_t = (*_note_iter)->time();
	}


	// Use the next note off iff it's earlier or the same time as the note on
	if ((!_active_notes.empty())) {
		if (_type == NIL || _active_notes.top()->end_time().to_double() <= earliest_t.to_double()) {
			_type      = NOTE_OFF;
			earliest_t = _active_notes.top()->end_time();
		}
	}


	// Use the next earliest controller iff it's earlier than the note event
	if (_control_iter != _control_iters.end() &&

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x42 · July 30, 2019, 7:25pm

and fixed in 6.0-pre0-2116-g8dbbc19567

sciurius · July 30, 2019, 9:27pm

Thanks!
Unfortunately I have problems building Ardour6 from git. Anyone want to look with me? Help is appreciated.

lenovens · July 31, 2019, 2:30pm

You probably don’t want to do that if the project is important to you. A session created in 6.0 today may not load in 6.0 tomorrow because 6.0 is still changing. The better thing to do is nudge the timing on things in 5.12

sciurius · July 31, 2019, 2:53pm

Rest assured, no way I’m going to use git builds for production!
But although I can (and do) build 5.12 flawlessly, it bugs me that current git is giving me strange compile/build errors. There are nightlies so it is buildable.

lminiero · March 1, 2020, 5:07pm

Apologies for bumping this old post, but it has just now come up while I was investigating the ordering of CC and notes, as part of an effort I’m working on: https://github.com/lminiero/musescore-vpo-midi-actions

Basically, I’m adding the delivery of MIDI actions from MuseScore in the form of custom CC messages, that I can then use to change articulation in an SFZ in Ardour, but I am indeed experiencing the CC being processed after the note. Since the fix is only available on Ardour 6, is there any workaround I can use for Ardour 5, e.g., to “nudge” all CC messages a bit before? I’m not scared of messing with the XML file, if that’s the only way