Synthesia drops the framerate randomly

[ofzatt]

Hi,
I'm using the latest version of Synthesia (10.5) and I found the software randomly dropping the framerate, though I am forced it to run with more than 13xx fps (set FrameMinMilliseconds to 0 and Vsync unchecked). With these settings, Framerate can be up to 16xx and Synthesia uses 45% CPU (i5 Haswell) and 80% GPU (750 Ti). The dropping bar is very smooth, but the software randomly flash drop frame while playing. And yes, I use synthesia with FL studio (via Loopmidi) and a windows video recorder. I tried the setup FrameMinMilliseconds to 1 and 2, but choppy is even more noticeable, although the framerate is very high (over 600 fps). What I need to do?

[Nicholas]

What do you mean by "randomly flash drop frame"? Does the screen actually flash?

I've noticed that unless the app is in full-screen mode (press Alt-Enter), that the OS (or graphics driver or something) seems to give it less priority than it should. Once in full-screen mode, things seem to proceed much more smoothly.

[ofzatt]

I dont know how to describe it. mean, it suddenly jerked. Here. this is more than 1400+ fps
https://www.youtube.com/watch?v=0mZ13gwLdz8

[Nicholas]

Yeah, those tiny hiccups are what I was talking about, too. Does switching to full-screen mode help make that happen less often?

[ofzatt]

not different, still flash drop .

[Nicholas]

I've also noticed that those sorts of tiny interruptions are very sensitive to the kinds of apps you have running in the background. Even just having a couple Chrome tabs open can make things a lot spikier. Does closing everything else (including non-essential notification area apps) help anything?

I'm not sure there is any way to make things perfect on a multitasking OS like Windows (vs. say, making Synthesia for a game console where the apps are allowed to have the full system's attention) and we could certainly do better with the some of the real-time programming in the app itself, but hopefully those steps help.

[ofzatt]

I tried: (FrameMinMilliseconds = 0, vsync = uncheck => ~ 1k3 fps, maximum CPU and GPU)
- Turn off loopmidi, using build-in sound + screen recorder
- Don't screen record, only play Synthesia with FL Studio VST
And FrameMinMilliseconds = 5, check vsync => 60 fps, play Synthesia with FL Studio VST and screen recorder
All 3 have "tiny hiccups", it is random at any time, maybe I will have to accept it, or repeat the process until good luck comes to me.

[Nicholas]

Were each of those tests done while in full-screen mode? Again, the Windows DWM seems to give a higher priority to full-screen apps. Speaking of priority, have you tried adjusting the Synthesia.exe process's priority to something like "High"? I haven't experimented with that much, but I don't suppose it could hurt.

Otherwise, some intermittent hiccups are still the fault of our own code. A lot of the deeper underlying assumptions of the play screen were made over twelve years ago, just a couple years after I was getting out of college and didn't know much better. It has only been in recent years that I've learned much of the programming style taught in schools (OOP) isn't the right answer for the near-realtime environment of 60Hz+ graphics apps. We've slowly been making strides in this area -- a little in every release -- so hopefully those sorts of inefficiencies will be fewer as time goes on.

(I actually keep a small, hand-written Post-It note copy of this tweet stuck to the side of my Synthesia dev machine's monitor.)

[ofzatt]

Still not clear, but there seems no "tiny hiccups" when I off all audio output (just checked on 1 song). I will check more when I have time, (and set priority to "hight", too). Because tiny hiccups do not affect the video so much, so maybe I'll accept it at this time