Black Desert Online: Desync 

Desync causes a lot of angst in BDO. But it is unavoidable and in my opinion it is not due to poor game design nor is it fully correctable regardless of what the developers do. The reason behind desync I think is a multifactorial but predictable process. This guide aims to demonstrate this process so that players understand why desync happens and can then improve their play to reduce it from happening. 

Abbreviations: of Ranger skills. SH = spirit Haven, ER=Elven Rage. EES=Evasive explosion Shot. RW=Rushing wind. BG= Blasting gust. GW=Guardian wind. Regen=Regeneration. FA=Fury arrow. Waltz=Waltz of the wind 

0. Why is there desync? (This is fact) 

If I play BDO NA from New Zealand. The information I input from my keyboard has to travel through thousands of kms of Fibre cable under the sea to reach the servers in North America where the game processes the information. I play against my guild mate in America, 2 kms from the server, his/her inputs only travels 2km to reach the server. It takes me 140ms and him/her 2ms for our inputs to reach the server. This time difference is UNAVOIDABLE because we all live different distances away from the server. Because of this difference in when our inputs will reach server, the game cannot show us exactly when our actions occur. It will always be a bit late. Each player will see the game at a slightly different point in time and this leads to 2 different possible versions of the same event occurring in the game. This is desynchronisation. These desyncs don’t really impact the game’s enjoyment nor gameplay including pvp in the vast majority of the time in my experience. 

A player’s ping can be reduced however if your connection to the server is unnecessarily convoluted. For example, my connection from New Zealand to US west is best via a straight line under the ocean from New Zealand to Hawaii to US west (140ms). But it could also connect backwards to Australia, then Singapore, then Hong Kong then Canada, then US west. The latter connection will mean an unnecessarily high ping for my game (280ms). You can check your connection path and optimise it using specialised VPNs. I have another guide for this: see my guide titled "latency/Ping optimisation" 

1. What happens to your inputs in BDO (This is just a theory abd does not explain all desync phenomenon yet) 

A theory that explains the desync we see in the 2 videos following need to account for why we see things such as:  

-Protection icons go off cool down and activate but the behaving as if they did not happen ("I got CCed through iframe/SA!") 

-CC icons going off cooldown and activating and failing to CC opponent who is non-protected 

-Why when the above happens, we do not see the activated CC or protection that failed to work appear on the opponent's screen 

-Why Grab activates and connects on one screen, Grab activates on the other player's screen but the game behaving like it does not connect in the end. 

The following is a Theory from what I have gathered mostly from other people. I'm not remotely experienced in computers/coding/networking etc so feel free to improve on what I have. 

3. A Theory of what happens after you press a button while playing BDO: 

say if if A's latency (latency = ping/2) to server = 10ms 

say if B's latency to server = 50ms 

-A presses grab next to B 

-grab immediately activates on A screen and connects to B on A screen (this is because BDO is programmed like so to make actions happen immediately on your screen. This is crucial to the feel of a fast paced action game. Imagine if all your inputs appear on screen only after the lag of reaching server and coming back to your screen - the game would feel terrible to play 

-grab command travels 10ms and reaches server 

-B presses windstep (a dash skill with iframe) iframe at the same point in time that A presses grab. On B screen, the grab has not displayed yet because A’s input has not reached server. 

-Windstep activates immediately on B screen 

-Windstep and iframe input travels 50ms to server 

-server receives grab connect data AND Windstep iframe avoid data and processes the information to determine an outcome. As we will see, when incongruent inputs are both received, the outcome favours failed grab. 

-server ticks (updates the game state and player's data) and the outcome is executed. Any data received after tick/update that doesn't make sense is ignored. Server ticks regularly every say...60 times a second 

-if A’s grab-connect data reaches server and the server ticks before B’s iframe avoid data reaches server, the server will ignore B’s input as if it never happened and execute grab connect KD outcome. B’s iframe input will never appear on A’s screen. 

-the updated information after every tick is transmitted back to the players Screens: 

-If B's windstep iframe reaches server after tick: 

-A sees grab connect and KDs opponent. A never sees B's windstep iframe 

-B sees windstep activate and move then gets rubberbanded back into grabbed KD animation.  

-If B's windstep iframe reaches server together with A’s grab data before tick: 

-A sees grab activate and connect to B then B is rubberbanded back to Windstep iframe animation 

-B sees windstep activate and A's grab go off but B doesn't get grabbed and windsteps away. 

The rubberbanding and getting CCed after a protection has gone off are what we call "desync" 

4. Desync examples with explanations according to the above theory 

Thank you to Korosan from Japan and Yuyanuu (Arsha outfit) from Taiwan for recording their duel and uploading their videos, allowing for the demonstration of desync. It looks like the duel occurred on Japan server. 

TW-->JPN ping = 150-220ms 

JPN->JPN ping = 7-20ms 

JPN video time = TW video time + 5:05 

Each example of desync has the time at which the event happens written from each players video's perspective. Then a description of the desync event is followed by an attempted explanation. Please slow the videos to see the occurences clearer 

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https://www.youtube.com/watch?v=a2CtEvIy1ss (JPN) 6:13/29:34 VS https://www.youtube.com/watch?v=645R0eSqbEY (TW) 1:07/24:14 

Iframe from TW never reaches JPN screen. Presumably after grab-connect and tick. So it got ignored by server. so server only received JPNgrab-TWguard connect. Grab lands. This is an example of failed protection from TW 

Theory: 

a.JPN grabs and activates on JPN screen. This is received by server because we see the grab on TW screen 

b.TW iframes and activates on TW screen.  

c.Server ticks. Server receives a grab-FG connect and executes a KD outcome 

d.TW iframe now reaches server but because it is after tick, it is ignored. No signs of TW's Iframe move is displayed on JPN screen 

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https://www.youtube.com/watch?v=a2CtEvIy1ss 8:33/29:34 VS https://www.youtube.com/watch?v=645R0eSqbEY 3:27/24:14 

Part 1: JPN screen: Grab went off CD while TW was in C-swap. TW disappears and manifests like 3 dashes distance away transiently then disappears again. SA from Grab displays while TW is blinking. Grab THEN connects on screen transiently-at the same time as TW is in iframe. Grab fails. 

TW screen: JPN not in SA after SH while TW is in C-swap - grab has started. TW goes into iframe while JPN is in early grab animation. SA from grab has displayed on TW screen-at the same time TW is already in iframe. Character connect animation never occurs i think. Grab failed. TW never teleports to 30m away. This is an example of cc and protections not working as they should 

Theory: 

a.JPNgrabs and activates on JPN screen. JPN grab reaches server because it appears on TW screen.  

b.TWiframe is also received because it is seen on JPN screen.  

c.Server sees a grab-FG connect AND a Grab-Iframe avoid. Ruling is of Avoid* 

d.Server ticks and updates the Avoid outcome 

Part 2: JPN Screen: JPN in idle. As TW's EES starts so does JPN's iframe (TW's EES starts pretty much at same time as JPN's iframe icon)  

TW screen: EES definitely starts and connects (JPN flinches) JPN's idle state. JPN then iframes. CC fails. 

Theory: 

a. TWees connect to JPN idle unprotected state received by the server. Received by server is proven by TWees displaying on JPN screen 

b. JPN's iframe state at the same time as TW's EES sent to server and also received because it is seen on TW screen 

c. Server receives stiff-iframe Avoid AND stiff-idle connection. Ruling is Avoid 

d. Server ticks and displays the Avoid outcome. Making it seem like a CC failed 

*Alternatively this could be because of a problem with TW's data being corrupted at server. TW actually transiently disappears and appears 30m away from JPN. ie. Server could've seen a Grab-nothing fail + Grab-iframe avoid, ruling a No KD outcome. 

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https://www.youtube.com/watch?v=a2CtEvIy1ss 6:48/29:34 VS https://www.youtube.com/watch?v=645R0eSqbEY 1:43/24:14 

At moment of inverse cone beam on both screens, JPN has already got waltz circular beams. TW still in invis phase of waltz. This demonstrates that what happens on TW screen is actually delayed and in the slight past.  

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https://www.youtube.com/watch?v=a2CtEvIy1ss 7:19/29:34 Vs https://www.youtube.com/watch?v=645R0eSqbEY 2:14/24:14 

JPN screen: JPN waltz has blade beams and is in CC range when TW is still in Waltz SA. On TW screen: TW has changed to S block after waltz but JPN is still pre-blades and outside of CC range. If TW had a GAP between waltzSA-Sblock TW be CCed. This demonstrates the importance of eliminating microgaps in protection 

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https://www.youtube.com/watch?v=a2CtEvIy1ss 8:36/29:34 VS https://www.youtube.com/watch?v=645R0eSqbEY 3:31/24:14 

TW ccs JPN during 2 consecutive unprotected moves. The timing difference is clearly seen by JPN screen displaying Regen animation further along.  

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https://www.youtube.com/watch?v=a2CtEvIy1ss 8:49/29.34 Vs https://www.youtube.com/watch?v=645R0eSqbEY 3:44/24:14 

TW's EES went on CD but this must have been ignored because it never displayed on JPN screen. Meaning it must have reached server after a tick. JPN Grabbed TW during Pariare SA state on JPN screen. This must've reached server and then the server ticked and updated the information before TW's iframe arrived. This is an example of a Protection seemingly not working  

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https://www.youtube.com/watch?v=a2CtEvIy1ss 9:15/29:34 Vs https://www.youtube.com/watch?v=645R0eSqbEY 4:09/24:14 

Again. TW iframe and CD goes off but this is ignored by server presumably after tick. Server only sees JPN grab connecting with Guard before tick and thus executes a KD outcome sent to both players. Another example of events being delayed on TW screen nd protection seemingly not working 

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https://www.youtube.com/watch?v=a2CtEvIy1ss 9:59/29:34 Vs https://www.youtube.com/watch?v=645R0eSqbEY 4:53/24:14 

JPN screen: 

JPNgrab starts when TWis in SA. Grab connects briefly. TW SA actually disappears so grab connected. Grab SA occurs. Then Grab disconnects at the same time TW is back in original position in iframe. Grab SA is now gone and rest of grab animation occurs all while TW is in iframe. Grab fails. 

TW screen: 

JPNrw SA ends and grab starts (no protection status period). Grab SA manifests briefly. No connection made from grab. TW is in iframe already at the before JPNgrab (no protection icon) starts. 

Theory: 

-JPNgrab connected on JPN screen and must have reached server cos we saw grab nd its SA appear on TW screen. 

-TWiframe reached server also as we see it on JPN's screen after the grab failed. 

-Server now has received JPNgrab-SA connection AND TWIframe-Grab connection presumably before tick 

-The outcome for a grab-SA=KD and Grab-Iframe=Avoid outcome seems to be Avoid again.  

-Server ticks and updates both screens to the grab-iframe = avoid outcome. 

The outcome for a mismatched CC + not-CC event seems to be in favour of the not-CC which I think makes sense and suggests the programming tries to accommodate for  

players with high latency. 

The second part of this shows JPN's iframe being ignored by server again probably it arrived later than a tick and TW's EES-idle=stiff has already reached server before the same tick. This demonstrates that having lower ping does not necessarily protect you from CCs. It is about the timing and luck with tick timing (presumably).  

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The following are all the other CC connect times. I've made some notes on the interesting ones. Remember the Coresponding time on Korosan's (JPN) videos is +5mins 5seconds to Yu's (TW) video time. 

TW 7:09 

TW 7:28 - Interesting that TW's RW ends in different locations on the 2 screens. 

TW 7:42 

TW 7:58 -Grabbed just before Waltz blades connect 

TW 8:17 8:31 

TW 9:02 9:06  

TW 10:07 

TW 10:45 - JPN ER Vs TW BG ER occurs both screens. Demonstrates the need to Conenct CC at the start of opponent's animtion s possible as opponent will always be ahead in time. 

TW 11:03 - TW FA Vs JPN BG demonstration of known mechanic where my CC loses it's CC effect if I am CCed before my connects. FA hits JPN first and JPN's BG does not CC TW. Some CCs don't behave this way e.g. pets/Kuno Ring 

TW 11:26 

TW 12:39 - JPN EES Vs TW Regen Regen activates on JPN screen but impact doesnt occur on JPN screen. Regen definitely impacts on TW screen. Demonstrates again the time delay between 2 screens. 

TW 12:55 

TW13:08 

TW 13:36 

TW13:58 

TW 14:20 14:54 

TW15:42 

TW 15:59 - JPN GW Vs TW Microgap. Demonstrates Protection fail desync. TW's Iframe got ignored. Demonstrates risk of microgaps. TW cannot trust opponent's state on TW screen. by the time TW sees GW animtion hit it is too late because GW has already hit in the past when TW was in brief protection Gap. 

TW16:23 

TW17:04  

TW 22:01 

TW 22:39 - JPN Waltz Vs TW Grab Demonstrates the difference in location of opponent between 2 screens. on TW screen JPN is right in front of TW at start of waltz blades not out. on JPN screen, They are far apart and Waltz blades are out, CCing TW during Grab gap. Interestingly, JPN ER are in 2 clearly different directions on the 2 screens. TW seems to be hit by ER on both screens however. Not sure how to explain the ER direction difference. TW Escapes ER KD possibly by immune and Stiffs JPN during Regen. 

TW BGs after. It is a BG-EES IFrame on JPN screen and BG-Stiff on TW screen. Outcome was No KD so presumably both data arrived within the same tick. The Same BG-EES is also a stiff (which connects on JPN screen just before the BG hits on JPN screen) Versus TW EES-EES avoid. So server actually receivs BG-EES + BG-Stiff + EES-BG. TW also EES after BG but this never shows up on JPN screen. Applying the theory it could be that BG-EES + BG-stiff was processed in the same tick giving a BG-EES = Avoid win ie. JPN screen input win. With this outcome it also means that JPN stiffs TW just before TW's BG hits making TW's BG a dud anyway. TW's EES then arrives next tick but it's ignored cos TW is already stiffed. 

5. How to avoid desync 

-Reduce ping. VPNs can do this by re-organising the connection from your computer to the server to the most direct route. A popular one is exitlag. But to see whether your connection is already optimised is bit more complex. I'll post a separate guide for this.  

-Protect yourself EARLIER. Stay FURTHER away. Don't trust what is on your screen. By the time you see your opponent approach within say 10m on your screen you are already behind. your opponent will be say 5m infrom of you according to the server. if you only react then, you will probably be too late. The higher your ping, the more this effect will be. Go into protection, move out of the way BEFORE what you see happens on your screen. Play more in anticipation of what might happen rather than reacting. This is not easy though and takes experience 

-Learn from your mistakes. If you constantly get desync phenomenon with certain skills use them earlier or use them from further away. or use a different skill altogether. Try to think what has happened at server side and adjust your playstyle to it 

-If you are trying to CC someone, remember the person's position is is an "afterimage" try to CC them at the start of their skills instead of very late into their skill's animation. the earlier you catch them on your screen, the more likely they are still in the same position according to the server. if you try to catch them at the last millisecond of their skill, chances are that server-side, their position has already moved on; OR worse they have already used another skill with iframe according to the server. This of course depends on the skill/experience of your opponent. Some people will actually just stay in one place and allow you to CC them - it's getting rarer though 

-Don't linger your skills or linger them less/change how you linger. Lingering is a key PVP technique to bait people but it also opens you up for being CCed. Constantly changing your position offers protection against what may have already happened on your opponent's screen/server. If you linger a skill to its full length then input a protected followup move, your linger may have run out at server side already before your next input is received. if your move still has a long protected linger time left before your input of the next move reaches server, your protection chain should be tight server-side 

-Get into the habit of being used to desync. After I press grab these days I automatically chain a protected movement skill expecting grab to fail/desync if you see desync happen and your action fail, move on. Reacting to it just makes you more exposed than expecting it to happen. of course, once you get more experience playing with desync desync event will happen less and if they do they will affect you less.  

-The higher your ping, the more you'll have to be mindful of the above information. But it doesn't condem you to being unable to perform in pvp. plenty of great players pvp at high levels and perform well with higher ping.