[MU4 Issue] Playback tempo is unsteady

[MarcSabatella]

Describe the bug
The tempo does not always remain constant, often sounding like a beginner trying to keep a steady tempo but just not quite pulling it off

To Reproduce
Steps to reproduce the behavior:

1. Load this score
2. Play

Result
It's just not even. The eighth notes are not all the same length. Almost but not quite like some sort of reverse swing is being applied - short-long, short-long, etc - but it's not consistently that either. It's just erratic.

Expected behavior
Playback should keep at least a steady tempo as I can :-)

Platform information

• OS: Linux, Windows

Additional context
This doesn't happen for all scores - at least, not to such a noticeable extent. But it's not just this one either. BTW, that particular copy of the score was created in 2.3.2, but I get the same result if I re-enter the first few measure directly into MU4.

[RazerMoon]

I'm also getting this exact issue, very annoying 😅

[MarcSabatella]

Is anyone looking at this? It's pretty bad, and even once new sounds are in place, it's going to be an embarrassment if people's first exposure to them is with scores that won't play with a steady tempo.

[Obliquely]

Agreed, it's very bad. I've encountered it on the last two scores I've tried playing back in MS4. I've spent a little bit of time trying to figure out what sets it off, but not got very far. Here's a short fragment where it does occur. It Kicks off at bar 5 for me. [Hallelujah (trunc).mscz.zip]

In playing around it seems that it doesn't always happen at the same time. It happens a lot in this score: [Here Comes the Sun (glitch).mscz.zip] but doesn't kick in until about halfway down the first page. And, it may not be linked but I noticed at the same time, I'm also getting strange variations in playback volume on this score. I noticed the two issues at the same time.

Hopefully have more score with the issue will help track it down. Is there some pattern in the score that's setting off the issue. Some score do seem to play back steadily. Or is it none at all?!

(https://github.com/musescore/MuseScore/files/9554438/Hallelujah.trunc.mscz.zip)

(https://github.com/musescore/MuseScore/files/9554485/Here.Comes.the.Sun.glitch.mscz.zip)

[MarcSabatella]

@Tantacrul - this is the issue I mentioned on Discord

[MarcSabatella]

FWIW, in case anyone is having trouble reproducing (for me it's 100% reproducible with this score on Linux and Windows), here is a video demonstration:

https://watch.screencastify.com/v/CbkUzqPU6wB85an3MCQn

[Tantacrul]

@MarcSabatella - we have a few bugs like this now. There's one where you provided a visual comparison using Audacity and also @bkunda's 'Uneveness' issue mentioned above. Am I good to close this as an issue that is reproduced elsewhere? If not, I'll reopen.

Also - is the issue any better?

[MarcSabatella]

Yes, it's fine to have closed this; I'm sure any of the reports are the same basic issue.

It's hard to say if it's better or not. Certainly not completely fixed. I think maybe it seems slightly better if I turn up the buffer size. But it's just prominent enough for me to be pretty sure it's not my imagination, but just subtle enough for there to be that little bit of doubt.

[Obliquely]

Just checked with most recent build and I'd say definitely quite a lot better than it was. Checking the two scores from my earlier comment, they are now listenable, whereas before they just weren't.