Factorio Forums

Hello all out there,

I would like to suggest to disable (maybe per swith) the saving of the replay in multiplayer.

In our (2 - 4 player) multiplayer ca 75% of the savefile is the replaysave. And since some of us (mainly me) have a lousy connection the distribution of the map after a desync takes loooong.

THIS IS BRILLIANT!!!

I would really like to see such a feature too. I started a multiplayer game in LAN and everything was fine, but we then tried to resume this via internet. With the ADSL3000 line the maximum upload rate is in the range of 300kBit/s which results in a connection time of 20min. Shaving of the reply data would make this much more bearable.

The dummy-mod-method should work in mp as well.

So basically you create an empty mod, share it with your companions, start a mp-game with it, save, deactivate mod, load, success. Didn't tested it though.

Needless to say I would prefer an official solution for that.

There is no need to resync all the replay data, since it has a "log" structure.
All the records before the actual desync should be just fine,
requiring only a handful of sych-check time windows to be resynced.
(The desync might AFAIK be in something that isn't checked,
so can't keep simple everything before the last passed check)

Perhaps CRCs can be made from the replay data, covering progressively larger part of the log,
perhaps halving the non-checked part each step: 0-50%, 0-75%, 0-87.5 %, 0-93.75%, 0-96.875%, etc.

Such CRCs would then be compared and last matching one used as a resync anchor.
PS: Since the series is infinite, one would need to define a stopping point, perhaps when the excluded "log" length falls below 100KB or something.

EDIT: I used python to generate those numbers: 100 - 100*( (0.5)**step)

alternatively, you can always go into the save and delete the replay.dat manually after each game session.

if what you say is true about the save being MOSTLY replay data, I would love to have it disabled. Or perhaps even just saved in a different file on the computer.

Since the game is deterministic, couldn't you just not send it with the map and have each player generate their own replay rather than all players sharing the same replay file?

I want faster join times as well, I would at least want to disable replays for now until the multiplayer is "finished" and the maps can send faster in some way (like a more robust changes detector or something, or a tree-based whatever, I can't remember how the other guy explained it)

I'm all for no replay data in MP, although we've barely explored in our map, I'm already noticing a SIGNIFICANT extra length of time to transmit the map to my friend than we were having a few days ago.

I've suggested disabling replays before, people were far too concerned that someone will try to fake a timerun in a savefile with no replay. (Easily fixed by not believing any savefile without a replay)

IMO Turning off replays needs to be a feature for multiplayer AND singleplayer and it would be nice if you didn't just suppress saving the information, but actually stopped the game from wasting cpu cycles recording player movements. Replays are a very cool feature, but being forced to save replays is an absolutely terrible feature.

I don't need replay for MP, that's the thing i delete when we load game again.

Yeah, removing replay would completely eliminate lagging for me since my upload speeds are absolutely abysmal.

I defninetely agree with this. To give an example with Numbers:
In my 18h coop game, the size of the save file is around 45MB, of which 34MB are for the replay.
But since Multiplayer in this version is officially only for LAN, where these file sizes are no problem, i'm pretty sure that the developers will improve this with 0.12