Pianoteq MIDI recordings are slow

These statements seem to be in conflict. If it's a MIDI recording problem, one would expect an export from any rendering app to exhibit the same sync error vs. the video. If it's only a problem with standalone Pianoteq exports, it's a rendering issue.

The issue in the other thread turned out to be that Standalone Pianoteq was rendering at a slightly lower tempo due to microsecond-level rounding of the duration of a tick. That issue was reportedly fixed in Pianoteq 6. Are you running the current release?

What's the tempo, and can you reproduce the problem at a tempo that isn't subject to rounding (e.g. 125bpm is exactly 500 us/tick)?

EDIT: I just tested exporting audio from Standalone Pianoteq 8.2.2 vs. rendering the VST3 in Cakewalk Sonar at 125 and 126bpm. There was no tempo drift between either pair of audio files. I then tried recorded MIDI simultaneously into Standalone Pianoteq and Cakewalk Sonar, and the final note events in each file were timestamped identically.

EDIT 2: I think what Julien is getting at is that clock-rate differences between the interface that Pianoteq is referencing and an unsynced video recorder can be on the order of .025% (as I recall) which amounts to about half a second over 30 minutes. If you don't sync the two recorders to a common clock source at the time of recording, you need to use video-editing software that can do it after the fact. I don't work with video much so am not sure if garden-variety editors have this capability built-in, but I would hope so.

I don't have the exact numbers, I will have to redo some tests later to measure. But if both audio are on, I will hear phasing even before the 10 minute mark. After that it becomes more like an echo.

EDIT: I just did a test recording for 13 minutes. After the 10 minute mark, there's a 1 second delay, almost exactly. What's more interesting is phasing happens almost instantly, even when I carefully aligned the first note.

Hum yeah that's not a small drift ! Unfortunately, I haven't managed to reproduce it. I've been comparing Pianoteq with Reaper, Logic and Synthesia and they all agree, up to a few hundredth of second per 10 minutes.

When recording MIDI, pianoteq measures the time using the soundcard: when your soundcard is configured to run at 48kHz, pianoteq assumes that each sample is 1/48000 second. So what could happen is that maybe your soundcard says it runs at say 48000 Hz, but in really it runs a slightly different sample rate. I have one that I have measured at 48003 Hz for example.

However, in order to explain a drift of 1 sec / 10 min, the sample rate deviation of your audio device would have to be around 80Hz, so I don't really believe it is the explanation. Still, I suggest you try to use a different soundcard (like the builtin audio of your macbook for example), and see if the result is different.

Re-reading this thread and the older one, it seems Pianoteq's offline (non-real-time) rendering of MIDI to audio may somehow be executing differently in different versions for the different platforms or under different O/S versions or CPUs. There hasn't been much mention of what hardware platform or O/S is involved in the various reports. My testing has been on an Intel system with Win11

Alternatively it seems possibly there is some procedural sequence of events that can cause Pianoteq to mis-read/mis-calculate/mis-store/mis-apply the microseconds/tick value corresponding to the specified tempo similar to the issue reportedly fixed in v 6.7.1.

When I have time, I'll give it another go using 120bpm, specifically.

Also, on the remote chance that it matters, what piano model, preset and rendering quaity are involved?

It would also be useful to know if you get the same slow/long performance when timing a real-time playback of the recorded MIDI.

I am still confused over your exact setup but find it curious that 23.976/24.000 is about .999 and 120.00/120.096 is approximately .9992. Is it possible the frame rate has been converted somehow?

As Julien wrote, Pianoteq is based on the sampling rate of the sound card used (internal or external), so in my opinion that's where you should be looking; if you could borrow an external sound card for a test, that would certainly be interesting.

You have already tried 3 different laptops, i.e. 3 different soundcards. Unless you need one it might be better to wait a bit until more is known about the problem, especially since you have something of a tempo workaround.

If you save the Pianoteq-recorded performance to MIDI and open each of those files one a time in a DAW, does the DAW take on the same tempo in both cases?

If so, and you drop the Pianoteq-recorded MIDI file back into Pianoteq after restarting it, will it then render the proper tempo?

Hopefully, this link* can shed light on this issue.

(Midi Beat Time)
"Within the MIDI data stream are tempo meta-events, which contain a 24-bit value that give the number of microseconds per quarter note."

(Sequencing Time)
"The fractional number of microseconds must be properly accounted for or the MIDI playback will drift away from the correctly synchronized time."

*
https://majicdesigns.github.io/MD_MIDIF...iming.html

Unfortunately, no, simply re-importing will not fix the issue. I have to modify the tempo to 120.096 using another program (Sekaiju). But in any case, if your Roland also sends note-off and you're not seeing the issue then that theory is bust... Oh well, I'm moving on for now. My Roland is 10+ years old now so eventually it'll have to be replaced. We'll see then if the issue is still there, lol!

Thanks for sharing. I've considered diving down this rabbit hole to attempt to make my own simple MIDI recorder, but that will take me forever to learn haha... For now I've made my peace with it. I thought the issue was happening to everyone, then it would have been easier for Modartt to diagnose. Whereas here it's only happening to me, and maybe the original poster from a few years ago - so I don't have super high hopes. I'm still going to test the different sample rates later to see if it makes any difference.

That's a very interesting observation. I've never paid any attention to that setting. I just tried setting it to 120/120.096 = .9992. This caused the UI to display 1.00x intead of 1x. And the resulting render was slow/long by the expected amount.

This made me wonder if that setting might account for the issue in some cases if not this one, but it seems to default back to 1x when you restart Pianoteq.

But it could still be part of the puzzle if it's not always being properly re-initialized internally.