[2020] Netcode & Lag explained with lots of examples - Rocket Science #16

Great video as always! I wanted to clarify some things mentioned in the video:

• Input buffer size is not the same for everyone. It tries to grow or shrink depending on network jitter (variance in latency).
• We allow up to 10 frames of input history to be sent on every outgoing packet. We don't send inputs that the server has already confirmed. You were probably only seeing 4 inputs because you had a low ping and the server had already confirmed the older inputs. If you increase your ping, you will see the game sending more inputs per packet.
• The networking options currently don't work because we chose to disable them via the backend while we narrow down server issues stemming from the last update. The networking options will be re-enabled shortly after the next update goes out.
• A fix was just checked in to our dev build a few days ago that coincidentally fixes the scoreboard ping issue too. The issue you are seeing is not the actual ping going up with increased FPS. The accuracy of the ping measurement is impoved with increased FPS. The fix will make it to the public in the next next update (couple of months?)

If that is true, then does that mean the server accepts inputs from some players later than others? That doesn't sound too fair to me. Or does your statement mean, that the client simulates even further ahead to create a bigger buffer for the inputs?

What it means is, if a player is averaging packets arriving anywhere between 100 and 125 ms of latency (25 ms of jitter), they have (ideally) 25ms of input buffer to ensure they always have enough inputs in the buffer to last until they next packet comes in. This keeps the input buffer as small as possible so we aren't adding too much extra delay to processing their inputs.

If another player has very high jitter (packets taking anywhere between 100 and 150 ms), they need a 50ms input buffer to handle the 50ms of possible lull between incoming packets.