Tempo Change Occurring "Inside" a Tied-Note

[mms]

Hello,

One (hopefully) last question on Tempo Change subject.

I created 2 test files (4/4 time) that both contain 4 bars each, and each measure plays a whole note.
Bar 1 has a metronome mark 1/4 = 60 bpm, and Bar 2 has a metronome mark 1/4 = 120 bpm

Test1a - all notes are un-tied - the created MIDI file has a duration of 10 seconds as expected (4s + 2s + 2s + 2s)
Test1b - note in bar 1&2 tied - the created MIDI file has a duration of 12 seconds (I expected 10 seconds here also)

How would your sequencers handle these?

It is hard to properly convey my meaning in words only, so I sent you 2 png files to demonstrate.

[JohnG]

Hello mms,

You're quite correct, the file should remain with a duration of 10 seconds, whether with or without tied notes crossing a tempo change.
It looks like the timing of the note that croses the tempo change is not being recalculated 'on the fly'.

JohnG.

[mms]

Thanks John,

I am a bit confused...

Are you saying that my sequencer is handling this situation incorrectly (making a 12 second MIDI file),
and your 3 sequencers each correctly produce 10 second MIDI files?

[JohnG]

May 28, 2021 11:54:07 GMT mms said:

Thanks John,

Are you saying that my sequencer is handling this situation incorrectly (making a 12 second MIDI file),
and your 3 sequencers each correctly produce 10 second MIDI files?

Yes, all of the sequencers I use correctly keep the duration at ten seconds regardless of tied notes.
After all, it's not the notes that are the key, it's the length of each measure.
One 4/4 measure at 60 bpm, three 4/4 measures at 120 bpm.

1st measure, 4 beats at 1 second per beat = 4 seconds.
3 measures at 2 beats per second = 6 seconds.
Total = 10 seconds.

It makes no difference at all what is inside each measure.
If a tempo change occurs, all notes need to be calculated/recalculated to fit.
Especially tricky when, very often, played in sequences feature notes that are short or overlong compared to their notated values, and not exact divisions of a beat.
That's musical interpretation, and MIDI sequencers (somehow) have to cope.

So for the long tied note, if the tempo remains unchanged, it would be held for eight seconds, but as it changes, the first half of the note is four seconds, but the second half is only two seconds long.
Does that make sense?

JohnG.

[mms]

Yes, that makes perfect sense (and that is what I was hoping). 

My playback indicator does move correctly for the 10 second file, while the MIDI file plays 12 seconds.

Could you please send me the correct MIDI file so I can examine the hex contents, so I can see what my
sequencer is doing wrong.

It makes no sense to me, as I thought I was sending the correct delta time for tempo change
in the Master Track.

[JohnG]

I don't believe it's the master track, it's the timing of the note that's tied that needs to be recalculated ... I think.
I.e., the Note Off position of the 1st note has to be changed.

Anyway, here's the file FourNotes (actually three!) attached.

FourNotes.mid (925 B)

Hope it proves useful.

JohnG.

[mms]

Thanks John,

FourNotes.mid was most useful in helping me fix my problem!
I could see where my timing issue actually was.
All works now as it should.

Thanks again.

[JohnG]

Pleased I could be of help.

JohnG.