Why are MIDI notes 1-2 samples ahead? 2022.9/2022.10

[gthm]

Why are MIDI notes a couple of samples ahead when I have clearly placed them on the grid? It happens with the first MIDI notes at the beginning of each session.

I start a session with a chord let's say, (at 0:0:000 right?) then I go to edit another track (audio or whatever) and when I come back to the Instrument track with the MIDI chord, the chord is now not snapped to the grid but has moved forward 1 or 2 samples (never more than 2 samples).

I opened some old sessions out of curiosity and there they are, MIDI notes are not snapped to the grid.

I noticed this in 2022.9, still there in 2022.10.

Very weird and annoying.

I hope I explained this right

Please see pic.

[daeron80]

The MIDI spec was developed in 1983 as a way to connect synthesizers to each other, and wasn't designed for sample accuracy. Its resolution is measured in ticks per beat, and is therefore tempo-dependent. I think the MIDI resolution in PT is officially 960 ppq. It wouldn't surprise me greatly if it were possible these days to place notes more precisely than the official spec designates. But it's not capable of being arbitrarily sample accurate since it's dividing beats rather than seconds.

[nednednerb]

That is a very specific and succinct and to me very reasonable answer.

If the MIDI note is moved in musical time, it's "exact" as "the tempo" (deviation from error or "randomness"), while on sample time, it's 48,000 kHz or 44,100, etc, meaning the deviation from "musical time" (in ticks) is related to the BPM being overlaid on a sample rate. There is a mathematical association, but 1-2 samples is VERY close. Good on them, hah!

[dcoffset]

MIDI is old but it also seems there are strange things going on inside some DAW's if you're after very precise timing.

Below is a post with some tests that demonstrates the issues in different DAW: https://www.admiralbumblebee.com/mus...-7-Mixbus.html

By the looks of it MIDI timing in Pro Tools can deviate according to the buffer size. I have also found this when doing drum replacement - on converting the virtual instrument track to audio, you notice that timing may drift (which is not ideal :/)

It's also important to differentiate between virtual instruments timing and MIDI hardware. The latter might have other issues that impact on timing that are not related to the DAW.

[climber]

BITD Dr.T's KCS on the Atari ST had incredibly accurate MIDI timing...