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Re: MIDI tick resolution
From: |
karl |
Subject: |
Re: MIDI tick resolution |
Date: |
Wed, 21 Mar 2018 13:32:40 +0100 (CET) |
Gilberto:
...
> Also keep in mind that tick resolution is given in pulses per quarter note
> (PPQ), not seconds. This means that a slow piece will have a lower
> resolution /in true time/, i.e. ticks per second.
I don't think resolution /in true time/ matters, since each tick is
"exact" in some sense.
What matters is the smallest subdivision of a quarter note used
(unless you use the smpte time format).
> Finally note that the
> reference is a quarter note, so if you have 384 PPQ, you then have 192 ticks
> per eighth note, 96 per sixteenth note, 48 per thirty-second-notes. Given
> that contemporary music can very much look like the image below, I think
> there is a strong case for higher PPQ in order to have decent
> representations of tuplets of very short note values:
>
> <http://lilypond.1069038.n5.nabble.com/file/t4165/maxresdefault.jpg>
(My wild guess is that music would need a tick value of 64*9*5*7.)
The technical limitation of midi file format is that the tick is a
15bit quantity, i.e. the maximum value is 2^15-1 = 32767.
(Instead of "ticks" you could use a time code based time, guess that
that is more for film making, don't know much about that.)
So you can't get 128*9*5*7 = 40320, but 64*9*5*7 = 20160 is possible,
and if you really need 128*9*5*7*11 or whatever, then you either need
to choose a format other than midi,
accept (smallish) time errors or
you have to scale the notes, say make a quarter a whole note or longa
(that would gain you a factor of 4 or 16).
All note times in the file is delta times, and they are of variable
length; the largest number allowed is 0x0FFFFFFF = 268435455, so if your
tick is 2^15 (finest subdivision), the longest time is slightly less
than 8192 quarter notes, which should be sufficient for most (all?)
music.
In effect, there is no need to choose a small tick value unless you
want smaller midi files (a consern which should be irrelevant today)
or perhaps due to some misbehaving midi equipment.
Regards,
/Karl Hammar
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- Re: MIDI tick resolution, (continued)
Re: MIDI tick resolution, Ivan Kuznetsov, 2018/03/19
- Re: MIDI tick resolution, Karlin High, 2018/03/19
- Re: MIDI tick resolution, Thomas Morley, 2018/03/20
- Re: MIDI tick resolution, David Kastrup, 2018/03/20
- Re: MIDI tick resolution, Gilberto Agostinho, 2018/03/20
- Re: MIDI tick resolution, Gilberto Agostinho, 2018/03/20
- Re: MIDI tick resolution,
karl <=
- Re: MIDI tick resolution, Gilberto Agostinho, 2018/03/21
- Re: MIDI tick resolution, karl, 2018/03/21
Re: MIDI tick resolution, Gilberto Agostinho, 2018/03/20