Frame pacing/stuttering issues in games (reicast)

Libretro Cores
#21

I had to rewrite my post since I fooled around with flycast some more, since its been a while.

For me at least, you can now just set Flycast to Fullspeed and leave the audio Synchronization enabled to get rid of the microstuttering I was seeing. Unfortunately, there’s still no way to get rid of the stuttering when enabling threaded and/or synchronous rendering, as now enabling the threaded rendering setting disables the framerate setting (as it should now). But the Vulkan renderer seems to help a lot with the frame pacing issues.

I recorded two videos to show how bad the stuttering is between fullspeed and threaded/synchronous rendering. I recommend watching these in a video player that supports exclusive fullscreen.

Fullspeed (little to no dropped frames in video, none in real time): https://mega.nz/#!oMQ01aoC!vP5pPUG9SYAEgQnA5CTy7Ur2PjPSVCas8Q4_lr3aN5E

Threaded/Synchronous video (lots of stuttering): https://mega.nz/#!MVYE3SpA!4O1xBYkhx988PuZ_gVMFiVQHv1n68lY-wTBgxdbzf4Q

These two videos were made with the vulkan renderer.

#22

When i use GL, DOA 2 (naomi) runs at 60fps with the similar frame pacing issues as your second video. With threaded video enalbled in the core options it runs a bit smoother for me.

W̶h̶e̶n̶ ̶i̶ ̶u̶s̶e̶ ̶V̶u̶l̶k̶a̶n̶ ̶i̶t̶ ̶r̶u̶n̶s̶ ̶l̶i̶k̶e̶ ̶c̶r̶a̶p̶.̶ ̶I̶t̶ ̶l̶o̶o̶k̶s̶ ̶l̶i̶k̶e̶ ̶i̶t̶’̶s̶ ̶r̶u̶n̶n̶i̶n̶g̶ ̶a̶t̶ ̶3̶0̶f̶p̶s̶ ̶o̶r̶ ̶l̶o̶w̶e̶r̶ ̶a̶l̶l̶ ̶t̶h̶e̶ ̶t̶i̶m̶e̶.

Using Flycast i downloaded today from the buildbot.

#23

@GemaH what GPU are you using?

#24

GTX 1060.

Nevermind my previous post though. Made a fresh RA install and Vulkan is about the same as GL now.

Still, Threaded/Synchronous works much better for me. Without it i’m getting severe frame pacing issues. With it, i’m getting moderate frame pacing issues. If i also set my screen at 60hz, frame pacing issues become minimal (i have a 240hz screen).

They never completely go away though, in both GL and Vulkan.

1 Like
#25

Sorry to bump this thread but it’s the only one I can find that is related to Dreamcast emulation when used with VRR.

I’ve also have had a hard time getting my G-sync (native) monitor working with not just Flycast in Retroarch, but Redream and Demul as well. I’ve actually had the best luck with Demul in 60fps games in conjunction with an RTSS frame limit of 60fps, but there are still periodic stutters. I’ve also noticed how the frame pacing can degenerate over time which can be fixed (for a short time) by exiting and entering full screen. 30 fps games seem mostly impossible to get working well.

Is it just an issue with Dreamcast emulation in general? Can it ever be fixed? The lower input lag that G-sync provides is useful since Dreamcast emulators seem to have quite a bit of lag when used at a fixed 60hz refresh and normal vsync.