Netplay over LAN - input lag issue?

RetroArch General
#1

Hi, I’ve been trying to run Retroarch netplay over a LAN, and I have two issues with it.

1.) desync when using Runahead. Host and client start to show different behavior on screen pretty much as soon as the game starts. Very apparent on a fighting game where the AI will do different things, have different stages, etc.

2.) As soon as I host a game, I get maybe two frames of input lag, even in stateless mode. I’ve never measured it, but I definitely notice a delay when hosting is on. I’m playing on a wired LAN, so I don’t need rollback netplay or anything like that. I set all the input buffer settings to 0 but the lag is still there. Is there a way to disable all of that and go peer-to-peer stateless over a LAN? That plus getting Runahead working over netplay would be the best possible configuration for me, so I hope it can be done!

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#2

For 1: which core(s) are you using? I think runahead is supposed to be possible with netplay, but I haven’t tried it myself. Runahead is basically ‘netplay with yourself’, so it should technically work.

For 2: I assume by input buffer settings, you mean these?

  • Netplay Check Frames
  • Input Latency Frames
  • Input Latency Frames Range

if so, have you tried setting them to 1 instead of 0? I think if they get too low, it just kinda gets ignored (I seem to recall Gregor saying something about that once). I think stateless mode is going to actually feel more latent than regular mode because it needs to wait and process the inputs before moving forward instead of just plowing ahead and fixing mistakes later.

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#3

I have tried SNES 9x Current and FBneo, both do the same thing when runahead is on.

I’ve also tried the Input Latency Frames setting on 1 and 0, with stateless on and off. Sadly, the lag is still there with all combinations of those settings.

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#4

Those cores should be as solid as they come, yeah, so if they’re having problems, too, it’s probably unavoidable.

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#5

I don’t think this is a core issue, though, since it only happens when hosting starts. It feels like there’s a hard set amount of input latency frames, so if it could be set to 0 somehow, even if only for LAN and Stateless, that might solve this whole thing.

#6

Is it plausible to connect 2 lakka raspberry’s with an ethernet cable? I want to play a local multiplayer.

Thanks