Games & input lag.

The problem there was people being sloppy. The topic of lag was raised in the Framerate Analysis thread despite not being framerate anaylsis. People replied despite it being totally OT. Someone suggested starting a new thread but didn't have the gumption to actually start a new thread, and then someone said there wasn't a thread where, if they had gone about starting a thread, this one would have been raised as already in existence. finally I didn't bother to check and just moved these posts out of the wrong thread.

I don't get why people are so averse to starting new threads for new topics, and would rather stick everything unrelated into one epic uberthread!

Anyway, here is where we can talk about input lag. Specifically, why is it different between platforms on the same game? What is causing the delay with SF?

 

My TV is 1080p and I am running games on their native resolution which in most cases they are 720p and in very rare cases 1080p like Wipeout HD.

When you say that the game should play on the TV's natrive res does this suggest that I should force 1080p mode?

Also if the PS3 scaler has problems outputting 1080p which is the best solution for that?
This is very important for me to know since I am playing Tekken comptitively a lot, and one of the things I have noticed, when I play online with perfect connection quality (5 namely with some very competitive friends) even the moves with the fewest frames dont seem fast enough to counter some relatively slower moves coming from the competitor, resulting to my character responding slower in general.
In very many cases my Just frames moves arent fast enough to counter. Some might say this is most likely a connection lag. But knowing that both have identical connections and that both should have experienced similar issues, I suspect that there might be some TV lag in my part whereas the guy on the other side has less input lag.

 

I dont know anymore, the theory is that setting your console to scale, rather than your TV, produces less lag. The console can supposedly scale faster than the TV.

So for example on Xbox, you want to set the console to 1080P output (if you have a 1080P tv), rather than 720P (in which case the TV will scale it). This can be problematic on PS3 though, since I understand many PS3b games cant output 1080P due to the scaler problems.

Honestly though, lag is such a finicky business with such a ridiculous number of variables and little hard testing, I guess I wouldn't worry about it. Probably ten other unknown factors might influence the lag more than scaling, for all we know.

 

hello, sorry upping old topic. but looking it seems more talking about the things that add lag.

im curious why some game that lower the frame-rate = more lag.
this happen in BFBC2, Lost Planet, Witcher 2 (very noticable in this game), etc.

But some other game the frame rate can go very low with no input lag added (stay the same lag).
This happen in GTA IV. My game go as low as 10fps but the input lag still the same and a lot faster than The Witcher 2 at 30fps.

what causing GTA IV able to keep the input lag stable?

thanks

 

How have you measured the input lag during lower frame rates?

 

yes, i have measured it using frame by frame count. Its stay in 8 frames delay. (29fps Vs 13fps)

here the screen caps of the frame counting
http://www.gamexeon.com/forum/imagehosting/201107/44194e33719dc68d8.jpg
http://www.gamexeon.com/forum/imagehosting/201107/44194e33719da6543.jpg


in other game like witcher 2, i didnt frame count because it is already very noticable experience. In gta IV is feel the same, thus i counted frames.

 

Cool counting!

Maybe you could post more of your findings online, at least I would be really interested. Maybe some MW3 vs BF3 input lag measurement?

Sorry that I can't help you with your question though...

 

Most important thing is to separate the controller input from the screen refresh. You can have game logic running at for instance 60fps at all times (though some games like racing games do this even higher), and then have a completely or nearly completely asynchronous rendering of the graphics that belong to the game state. There are more factors involved, but this is by far the most dramatic. If this separation isn't in the game's code, then allowing your screen to tear and double vs triple buffering can also affect the experience.

 

@tuna
^^ seems interesting checking those game in Xbox version (30fps bf3, 60fps MW3) it will be hilarious if the result is BF3 have lower input lag than MW3

btw bonus framecount : witcher 2
http://www.gamexeon.com/forum/imagehosting/201107/44194e34d6a45f578.jpg
http://www.gamexeon.com/forum/imagehosting/201107/44194e34d6a47a70d.jpg

@arwin
wow thanks a lot. Thats clears my couriousity

btw i also tried GTA IV only in 1 cpu core. The result still same 8 frames delay. Seems the controller input is given very high priority (and async).

 

Posted here to avoid going further off topic in the "predict next gen tech" thread...

I remeber Carmack making comments that the current 66/100+ms situation is far from optimal. I was wondering - was that a general comment on the way the hardware works or is there something about the way the current gen hardware was designed that inflates that number? From my understanding, it takes 33ms to render a frame in a 30fps game while the transmission of the signal from the controller to the console probably takes a few miliseconds tops. Yet the total lag can exceed 133ms. Looking at this thread there are reasons given for that but... Could that be adressed when designing next gen console or this is pretty much how things work(and it can even get worse as some are suggesting!)? Would it be possible to get lower than 100ms for a 30hz game?

 

A lot of the input lag comes from the display. Most HDTV's sold have cheapish {P/M}VA panels that do a lot of signal preprocessing to hide their awful pixel response times. This adds several frames worth of lag to every frame. This is not as much of a problem on the PC, because there most cheap displays use TN panels, where the image quality is crap, but at least they are fast.

 

Sure but that's additional lag from the display. I was courious if there's anything that can be done with the delay caused by the console hardware.

 

There is no inherent delay in the console hardware. None of the console scalers I'm aware of add frames.
Games generally add between 1 and 2 frames, depending on how things are split out.
The rest is the display.

 

Games can add a lot more than that. Lowest 60fps can get is 50ms. The best 60fps games manage 66ms, among which Burnout. Best 30fps game does 83ms or so iirc, but usually they are 100ms or higher. There is a good Digital Foundry article on the subject, which also has some interesting follow ups.

http://www.eurogamer.net/articles/digitalfoundry-lag-factor-article

 

I can believe those numbers.
In the simplest form, you have a worst case of 1 frame from the time a button is pressed to it being "read" at the start of a frame, the frame it's rendered in, then 16ms for the image to be drawn (assuming no additional display lag).
~48ms, though on average you only lose 8ms for the "read" so it's more like 40ms.
Double that for a 30fps game.

practically most games add 1 additional frame if they spit gameplay from the rendering thread.

If they run the gameplay thread asynchronously and interpolate all bets are off.

 

Thanks, that explains a lot. I was just looking for those missing "puzzles" that increase the total amount of lag to over 100ms, on top of the 33ms spent rendering the frame.

 

Yeah, I assume 4ms for the controller, which can cross the 16ms border like this:

Code:

0 --------- 16.6 -------- 33,3 ms
          x --- 4 ms

, and maybe is even forced to to prevent inconsistent response?

Then you get the next 16,6 for drawing the frame, the next 16,6 for making that frame the framebuffer, and then it needs to be drawn.

I vaguely recall reading that some Nintendo stuff, not sure if it was GameCube or handheld, is 2-3 frames generally.

 

How fast did old CRT's like in NES days refresh?

I wonder what the input lag of a NES game was like?

 

60hz for NTSC and 50hz for PAL.