Very high input lag in PPSSPP core

Libretro Cores
#1

I tried a few games and they all seem hard to play since they go as far as having 7 frames of lag. Ultimate Ghost and Goblins is practically unplayable since the game itself is hard enough. Same thing with the Metal Slug games. I think the fastest game with the lowest input lag was LittleBigPlanet with 4-5 frames of lag (which is still high). This places the PPSSPP core at the top spot of the slowest cores, beating Mednafen Saturn even.

I tested this with GPU sync ON and zero frames on a CRT monitor. That makes it the optimal, fastest possible setting outside using frame advance. I don’t even want to know how bad it will be on a LCD.

What i do want to know is if this is a known problem with PPSSPP in general. At this state, you can’t play most games on it IMO.

#2

Standalone PPSSPP seems to have just as bad input lag. I’m trying to play Ghosts n Goblins but it’s pretty much unplayable. I didn’t know the emulator suffers from this, i was hearing only good things about it for so long… Until i decided to try it. Unless the real PSP is as bad which i doubt. Can someone confirm though?

Also, the latency settings have no effect on the core.

#3

I finished GnG Kai, MM Powered Up and MHX last year in the core without issue. But I think input lag is harder for me to notice in polygonal games, especially when they’re 30FPS. I just sort of expect them to be less precise and responsive than 2D 60FPS. And I think I was still using a 2014 based core at that point. I haven’t played much PSP stuff since the core was updated, but it didn’t seem noticeably worse than the older core.

#4

Yes PPSSPP has an unusual high input lag: PPSSPP: 6 frames of internal latency

I have a real PSP myself and input response is much much better on the real hardware.

It’s my personal opinion that the issue is not with Retroarch but with standalone PPSSPP.

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#5

I was trying to play Gradius IV from Gradius Collection and noticed 6 frames of lag in ppsspp libretro.

I tried it on stand-alone and it has 5 or 6 frames of lag, hard to tell as the screen isn’t refreshed for more than a blink when using “next frame”.
I changed the rendering from buffered to unbuffered: now “next frame” stays on screen and there’s only 1 frame of lag!
This will probably remove some effects in some games I assume though.
(edit: indeed, no picture at all in gradius 3 lol.)

Back to RA I try to set it to nonbuffered but the picture is upside down and mirrored, crashes on restart.

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#6

This reminds me of Framebuffer in N64 emulators. It causes input lag in some games (not all) but with other side effects.

Thanks for confirming the issue. And yeah, it’s a problem with the standalone. Unfortunately, the latency options RetroArch provides don’t help in this case.

#7

Yeah in mupen (gliden64, upstream too) it’s really bad in games like mario64, wave race, rally '99…

#8

@GemaH Today I enabled this core, and I’ve been experiencing the exact same thing. I tried Star Wars Battlefront Elite Squadron and Castlevania - The Dracula X Chronicles, and the input lag made both games unplayable. On Castlevania, specifically, I used the method outlined in a Libretro post (which I can’t seem to find) where you hit “P” to pause emulation, hold the jump button and press “K” repeatedly until your character jumps. It took 4 "K"s before he moved.

I’ve tried Vulkan, glcore and d3d11 (which crashes instantly, despite GTX 970 supporting it). I’ve also messed around with latency, Locked CPU Speed, frameskip and Vsync settings. Nothing seems to fix it, yet I’ve read several post where people say they don’t have any input lag, whatsoever. Are they simply insensitive to it, or do I have a problem with my build. I can’t imagine someone playing through an action/platformer and not noticing when they’re thumb has pressed, then completely come off the button before their character jumps.

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#9

The lag is there. Not only in the core but on the standalone as well, the author of the emulator himself agreed that newer versions are worse due to some multicore function in order to make the emulator faster. Though i think the standalone is OK if you use D3D.

As for people not noticing the lag, well, input lag is an even more subtle thing than small frame rate differences or microstutters. There are people who have a hard time noticing even something as big as 30 vs 60fps. I would not expect them to be sensitive enough to notice a few frames of added lag.

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#10

I realized I was using a core from before the lag was added in my previous post in this thread. I tried a newer build a few months ago and felt a little lag in GnG Kai, so I’ve stuck with the older one.

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#11

Still the same, when can we expect some updates?

#12

While it does need some TLC, the high input latency exists in standalone, as well, AFAIK.

#13

Υes it exists on the standalone. A sacrifice for weak mobile devices that even users of capable PCs have to deal with. A real shame IMO this completely ruined this fine emulator for me.

Author said direct 3D is faster and indeed it is. But its less compatible so pick your poison.

#14

Yeah, I’ve noticed this as well ever since I’ve used PPSSPP from years ago. I play a lot of fighting games, which requires split second reaction timing, and this makes most fighting games unplayable.

I really hope they fix this! Fingers crossed this will be a priority for the PPSSPP development team.

#15

I can confirm that the lag occues in PPSSPP standalone as well. I tried the run ahead feature, but my pc doesn’t seem to be powerful enough to handle it. RA crashes immediately after anabling run ahead.

#16

Runahead just doesn’t work with hardware-rendered cores, unfortunately. :frowning:

#17

Glad to see it’s not just me with this problem.

Made a tread about my struggle with what metal slugs a should play. https://forums.libretro.com/t/metal-slug-7-or-metal-slug-xx/26478

BTW, does anyone know if its possible to find an old version of this core not surrendering from this bug.

BTW 2, I chose the DS version over the PSP version i case you where wondering.

#18

The d3d11 driver has 2 or 3 fewer frames with this core than openGL, I think.

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#19

If you have an Nvidia card you can try the global enable switch for Ultra Low Latency as well and see if that affects anything. I don’t know how PPSSPP handles it’s borderless mode in Windows 10 , whether it uses flipmodel or not. But on Windows 7, you can use PPSSPP standalone with Scanline Sync from RTSS (You have to disable the internal framerate limiter and make sure duplicate frames for 30hz games is turned on) and get really decent latency since there won’t be any added latency from the compositor+Vsync. Scanline Sync is finicky to get it just right and there can be glitches sometimes. But when it works it works great.

DX11 definitely has the least latency. UGnG with DX11+SS feels almost as responsive as real hardware. DX9 is close second. Vulkan and OGL have a bit more latency.

#20

The lag is at the emulator level, so unfortunately doing those things will not fix it. Standalone ppsspp has the option to shave off 2 frames of input lag but that still leaves 3 or 4 which is still far too high.