Google sure has some bold plans for its Stadia game streaming service: “negative latency.”
Google vice president of engineering Madj Bakar told Edge magazine in a recent interview that the company believes it can make streaming games respond faster than a game would if it was running directly on a PC or console, per PCGamesN. Two ways of beating any potential lag between players and Stadia servers are mentioned: rapidly increasing FPS to reduce latency between when a player takes an action and when it’s displayed on the screen, as well as a predictive model that anticipates player inputs and processes them in advance.
“Ultimately, we think in a year or two we’ll have games that are running faster and feel more responsive in the cloud than they do locally, regardless of how powerful the local machine is,” Bakar told Edge, adding that Google characterises this as “negative latency.”
Obviously there is no such thing as “negative latency,” which seems more like marketing jargon than anything. As PC Gamer noted, one game developer on Twitter suspected that the predictive button pressing feature is not some kind of promise that Stadia will come with aim assist or press buttons for players”that would kind of ruin the experience”but instead is just branding talk for branch prediction. That’s a well-known performance trick in programming relying on guesswork, but could run the risk of significant desyncing or rubber banding in fast-paced games. Predictive modelling can be used to generate frames in the cloud in advance and then only display the one to the player that matches with the action they actually take, but with the caveat that it takes a lot more bandwidth. (In a very loose sense, Stadia would indeed be rendering the game microseconds in advance of the player, not that this is actually new to gaming.)
Note that none of these are actually “negative latency,” which is impossible from the player’s perspective due to causality.
In any case, while there’s a lot of interest in Stadia, the service has also come under scepticism that it will actually run anywhere near as well as promised. with shitty internet.