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Killer In-Sync? (Update: Not really)
- Thread starter Unison
- Start date
But, dude, he can hear people breathing. Everyone knows software works 100% accurately if there is a breathing human within the vicinity.
Yeah that's true and I don't think it happens that often, just wanted to point out that it looks like you don't necessarily notice when it happens.
Parakeetman
No one wants a throne you've been sitting on!
Btw OP maybe you should request for a mod-edit of the thread title so more folks actually have a better idea of what your post is about.
abstract alien
Member
hang on, how is it not exactly what is going on? the opponents aren't moving to the exact same inputs on both videos. some are similar when the sync drops in and out. at the point of the de-sync, the game is stepping in to smooth the match out. at that point you're fighting AI. AI doesn't need to be an AI opponent in the sense of going into arcade mode and fighting the computer, but it can be the game stepping in and controlling the desync opponent. So how have I not comprehended what is going on again?
SneakyStephan
Banned
Examples?
A lot of the time the characters are in different animation states because they've been hit or something, so the moves come out differently. But I didn't see anyone make a completely different movement on one screen than on another.
AkimbO_Arcana
Banned
LOL?
Net_Wrecker
Member
So....hold on
wait wait wait
you're telling me
*watches video*
wut
wait wait wait
you're telling me
*watches video*
wut
abstract alien
Member
Damn that got me lol
I assume it's pretty low based on your connection, we have more reports on good fights than lagged ones. I most of the times play with my headset on and never had anything like a desync happening.
Passive Assassin
Member
IT WAS LAGGING GUYS
They're littered throughout the video. I'm not saying it's an AI opponent but there is AI taking reign and you're fighting it when the desync happens, paired with the delayed inputs coming through. The game has to be taking control at some point, it's not a cut-dry case of the inputs just being delayed.
Kocolino67
Member
It's the first time I've seen a DSP video where he isnt crying and yelling "I'm not doing anything!"
AI would have nothing to do with that, as far as I can tell it's just a desyc of the action while still keeping all of the inputs. If one side of the net is basically saying this move hit the player, the combo starts. The other side is saying the move was blocked so the move didn't hit, and KI's combos require a ton of rapid button inputs after so you see random special moves as the inputs are still being read. You see it a lot while Sadira is full screen away while doing a combo in one match, she's standing there throwing out random moves on the other.
GGPO is supposed to roll back the action when it encounters lag which can lead to weird stuff like landing a KO in third strike and having it immediately go back before the last hit and maybe you get hit instead. This seems like an issue where that rollback got messed up.
Kocolino67
Member
If there is really an AI playing while de-synch, then it was in front of our eyes all the time...
While I'm not Double Helix, I can try. This is some serious issue with their lockstep networking.
Most if not all fighting games use a form of lockstep networking. This means the session networks your button inputs and ONLY your button inputs. Sometimes some extra data, but due to the nature of lockstep you want to be sending minimal information down the wire.
The best way to think of lockstep networking is you're playing on your console. Your console then simulates an invisible Controller 2 plugged into your console having it's button's pressed. The buttons it presses it gets from the other person over the internet. For all the simulation knows, someone is actually playing with you on the same Xbox. Your button presses are sent the same way to the other person's console.
Life bar / health data is not sent over the network in lockstep usually, so not surprised to see the lifebars not update in sync. Neither person is truly host, it's up to the lockstep networking working correctly for both boxes to stay in sync with health bar information.
It's legit. The simulations drifted apart, but the button presses are still being received and processed.
Yep. It gets a couple of lucky resyncs, but drifts again. They're doing the same moves in different positions because their Xbox is receiving the button inputs and playing them on the local simulation.
Rollback needs a proper state to work. The state went out the door and has taken a bus on a shopping trip. It'll be back in 5 hours.
And this might be a deep engine issue if LOCAL replays drift. The interesting thing about lockstep networking is if you get lockstep networking working in the first place, you pretty much have most of the groundwork to do local game films and replays. If a film can drift, this means the engine may be having determinism problems. It could be a specific move is bugged, the input playback engine is bugged, or the simulation's framerate is not properly being accounted for and a drift occurs there.
Determinism is the idea that an action will always result in the same reaction across all boxes in the session when you press a button. For an example, in Halo firefight: I press the B button to melee. Everyone else's box sees me press B, my Spartan punches on their box. My punch was in front of an Elite, which connects with the elite. The boxes all know the elite should be dealt 25 damage, and the Elite should play his rage animation. The HP of my spartan or the elite and the engine command to play the animation are not networked. Only the button press. So that effects or AI won't respond the same way every time you play the game, boxes will share a random seed at the start of the session, and they'll use this seed so the dice rolls always end up the same way for everyone.
Lockstep is great when it works but it will bite you in the ass hard if you let it desync. Async (like versus mode in FPS, MMOs) can fix itself but it also consumes tons more bandwidth and by it's nature, everyone is slightly out of sync for the entire game - something you don't want in a fighting game.
It's certainly fixable, but there's definitely a bug in the engine here, and doubly so if drifting occurs in local replays.
No AI is taking over. The button inputs from the other player are being processed, but since the simulations have drifted apart, the same button inputs won't always produce the same output on both boxes.
If AI takeover was a thing, it would have noticed DSP's box shut off the networking when he went to the victory screen because the match was over (hence why the other player just freezes - they're not longer being fed inputs, so the networking is properly waiting for new inputs to arrive), assume DSP left, and replace him with an AI.
I can't see any case of something happening on one screen that isn't matched by inputs on another. The closest thing to it (at 1:36 in the video), where Sadira jumps on Calve's screen and does a spin-in on DSP's, actually corresponds to two QCF+Attack commands on Calve's screen. Blockstun in the DSP game ate the jump command, while Glacius's attack didn't come out at all in Calve's game.
You're gonna need to give me some evidence. Having an AI waiting in the background to pick up the slack if a desync is detected instead of just rolling back using the GGPO code they're already running isn't just significantly more resource-intensive from a development standpoint; it isn't an actual solution to the problem, and it's something that would piss people off if they noticed it (and they would, since it changes match outcomes). Simple bugginess is much more likely than the developers being dicks to their audience for no reason.
EDIT: Also, if there were an AI, all matches would conclude, since the AI could just finish regardless.
Dwight Schrute
Member
Wow if true...
You're right, I used to notice this heaps when I'd play 3s over GGPO. Sorry for the snark earlier folks.
How come? Never heard of him
Nice post! Pretty interesting stuff.
I can try to fool around with it some more tomorrow to see how common it is locally, anyway.
Dynamite Shikoku
Congratulations, you really deserve it!
If this was widespread, I assume people would have noticed it already
toastyToast
Member
FineEdgeGames1 day ago said:
lmao
This is some next level shit. I got a headache watching that video
Telephoto999
Member
They have.
All of my friends playing the game say they get "quitters" and connection droppers all the time when they start winning the match.
I'm starting to think this isn't the other player quitting, so much as it is the game losing sync so badly and this bug occuring. It would explain why there is currently no punishment for a player leaving a match mid way through.
Look for one of his videos on Youtube. Nothing is ever his fault.
Telephoto999
Member
Also, this explains why no one... despite literally playing all over the US has experienced any sort of rubberband or pausing during gameplay. It's simply impossible due to latency, network structures and packet loss to have as smooth of an experience as this game portrays. I didn't realize the problem was this bad... but when literally everyone bragged about how awesome it was playing this game and how it felt "local" , there just had to be some weirdness going on behind the scenes.
I've definitely experienced pausing in some matches.
PapaJustify
Member
Personally I think this is quite a smart solution to fill the inevitable gaps in connections in such fast paced games. Even better if the AI learns from your opponent and actually anticipates what the opponent WOULD do. Connections won't get better anytime soon, so I think this pretty cool. And people didn't notice the difference, which makes it pretty impressive also.
The thing about online networking, whether lockstep or async, is everyone assumes it's a magic switch you throw and a game is online, and it's cases like this where the multi-verse puppet show that it really is gets exposed.
Telephoto999
Member
When you get completely different match outcomes, which effects ranks and records in a competitive environment... how is that okay?
There are definitely pauses and normal lag situations even if the netcode is all around really solid. It also has different messages for a quitter vs. connection dropped.
Well this explains a lot. When a friend and I are playing online, there has been times when we would both win the match. On my end I would have already won for instance and then all of a sudden he'd be saying that he won, or vice versa. Now we have an explanation as to why.... =/
Fudgepuppy
Banned
Just imagine the fights at the schoolyard when kids will call each other quitters and losers, when it's just the game screwing them over.
I feel stupid for believing in the AI theory after watching the video again.
Killer Instinct "feels local" because it has rollback multiplayer instead of an input lag system (which means you don't have to adjust timing as much). It still has noticeable lag sometimes like other GGPO titles.
If you look at the posts here, what happened was a desynch where commands were recorded but the result often wasn't. While that's a colossal bug, it's not something you intentionally program.
Killer Instinct "feels local" because it has rollback multiplayer instead of an input lag system (which means you don't have to adjust timing as much). It still has noticeable lag sometimes like other GGPO titles.