Measuring Input Latency In Console Games 160
The Digital Foundry blog has an article about measuring an important but often nebulous aspect of console gameplay: input lag. Using a video camera and a custom input monitor made by console modder Ben Heck, and after calibrating for display lag, they tested a variety of games to an accuracy of one video frame in order to determine the latency between pressing a button and seeing its effect on the screen. Quoting:
"If a proven methodology can be put into place, games reviewers can better inform their readers, but more importantly developers can benefit in helping to eliminate unwanted lag from their code. ... It's fair to say that players today have become conditioned to what the truly hardcore PC gamers would consider to be almost unacceptably high levels of latency to the point where cloud gaming services such as OnLive and Gaikai rely heavily upon it. The average videogame runs at 30fps, and appears to have an average lag in the region of 133ms. On top of that is additional delay from the display itself, bringing the overall latency to around 166ms. Assuming that the most ultra-PC gaming set-up has a latency less than one third of that, this is good news for cloud gaming in that there's a good 80ms or so window for game video to be transmitted from client to server."
Transfers to PC Game Ports too... (Score:5, Interesting)
Reality check (Score:5, Interesting)
...average lag in the region of 133ms. On top of that is additional delay from the display itself, bringing the overall latency to around 166ms.
Considering that until very recently all displays had an inherent lag of about 70ms -- and that new [LCD] technology has pushed that higher. But we're only considering half the equation: The average human response time for auditory or visual input is 160--220ms. This increases as we age. We are also part of this system and we're a helluva lot more lagged than our technology is.
I want an upgrade.
DDR? (Score:3, Interesting)
Anyone can make a comment how the lags affect gameplay on DDR? I still hesitate to buy an LCD TV and stay with my CRT, because I am not sure about it. When playing DDR, I usually listen to the music and the rhythm, so I really don't know exactly what would happen with a LCD TV.
I've seen people playing DDR with Samsung LCD TVs on Youtube. It seems it's working well.
Re:Transfers to PC Game Ports too... (Score:3, Interesting)
Re:Reality check (Score:4, Interesting)
The only inherent display latency of a CRT is the time taken for the beam to arrive at any particular part of the screen. In the worst case this is one frame, which at a reasonable refresh rate (100Hz+) will be only 10ms or less. A good LCD (there's only one on the market, the ViewSonic VX2268wm) updates in the same line by line fashion as a CRT, and will add only a few more milliseconds switching time latency.
Of course you still have the latency in the input/processing/rendering stages, but this doesn't have to be very high (increase input sampling rate, avoid any interpolation, disable graphics buffering, etc). The only reason most modern console games are unplayable is because reviewers all ignore latency, and low latency can be traded for higher graphics detail which the reviewers pay attention to.
Perceived latency has nothing to do with reaction time.
The latency issue with the Wii. (Score:2, Interesting)
I wonder what Rich Hilleman was really getting at? Maybe people are more sensitive to delays when they are a result of a full-body-type movements rather than a button-press.
This is interesting stuff, and it would be a good thing if some graduate student did a thesis on it. (Free Ph.D. here--no thinking required!)
-Todd