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John Carmack: Latency Mitigation Strategies

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Re: John Carmack: Latency Mitigation Strategies

#11

Post by neverm0re »

modeless wrote: post #7
micheljansen wrote: post #6

Earlier quoted context omitted.

I think the monumental failure of Nintendo's Virtual Boy pretty strongly illustrated that if you can't do this perfectly, you shouldn't do it at all. Within the current constraints (including budget), making a "good enough" product is clearly not feasible. As this article points out, even a few milliseconds too much causes massive problems (worst case: severe nausea – car sickness). On top of that, it's not even clea…

Virtual Boy pretty strongly illustrated that if you can't do this perfectly, you shouldn't do it at all. Absolutely. But the Virtual Boy was clearly before its time. The hardware just wasn't ready. Within the current constraints (including budget), making a "good enough" product is clearly not feasible. I think that's clearly not true. The response from everyone who's tried the Oculus Rift has been that real VR has f…

> Specifically, they could source a higher-res, higher frame rate, lighter, lower-latency OLED display

None of those are actually remotely as important as the fact you're still using your head as a dumb camera joystick, there's no ability to track eye movement and the mismatch between what you're seeing and your inner-ear pressure is going to make a number of people throw up.[1]

These are fundamental problems that have been a part of HMDs for the last twenty years of me playing with them and the Rift addresses absolutely none of them. The Rift itself is not significantly different than its HMD contemporaries, it's actually aiming for the low-end gamer market and so far seems to be mostly pushing 'What's old is new again' without having made significant progress along the way. The most interesting part of the Rift kit is the tracker, not the actual HMD itself.

[1]: In a study conducted by U.S. Army Research Institute for the Behavioral and Social Sciences in a report published May 1995 titled "Technical Report 1027 - Simulator Sickness in Virtual Environments", out of 742 pilot exposures from 11 military flight simulators, "approximately half of the pilots (334) reported post-effects of some kind: 250 (34%) reported that symptoms dissipated in less than 1 hour, 44 (6%) reported that symptoms lasted longer than 4 hours, and 28 (4%) reported that symptoms lasted longer than 6 hours. There were also 4 (1%) reported cases of spontaneously occurring flashbacks."

Read up on 'Simulation Sickness' for more details.

Re: John Carmack: Latency Mitigation Strategies

#12

Post by dchichkov »

> Conventional computer interfaces are generally not as latency demanding as virtual reality, but sensitive users can tell the difference in mouse response down to the same 20 milliseconds or so, making it worthwhile to apply these techniques even in applications without a VR focus.

I wish people would start treating text editors that they are developing this way. As hard real time systems. Don't care much about virtual reality, but I'm sick of text (and code) editors with unpredictable latency of basic operations [like typing a character, making find call, etc].

Re: John Carmack: Latency Mitigation Strategies

#13

Post by mtgx »

modeless wrote: post #2

I think head-mounted-display virtual reality is a huge missed opportunity for next-gen consoles. They could have really done it right in a way that PCs can't yet, with special hardware support for low latency and stereo rendering, and a guaranteed large audience so game studios could justify applying their full budgets to AAA VR titles. It would be a huge differentiator at a time when consoles seem to be converging t…

Well Oculus Rift should support everything from PC's to consoles. But I agree. Stuff like Oculus Rift is the true next-gen computing. The PS4 and next Xbox leave me pretty cold, especially when I already have a laptop that can already play all the latest games.

Re: John Carmack: Latency Mitigation Strategies

#14

Post by modeless »

dchichkov wrote: post #12

> Conventional computer interfaces are generally not as latency demanding as virtual reality, but sensitive users can tell the difference in mouse response down to the same 20 milliseconds or so, making it worthwhile to apply these techniques even in applications without a VR focus. I wish people would start treating text editors that they are developing this way. As hard real time systems. Don't care much about virt…

Have you tried Sublime Text? Predictable low latency is one of the reasons I like it.

Re: John Carmack: Latency Mitigation Strategies

#15

Post by dman »

dchichkov wrote: post #12

> Conventional computer interfaces are generally not as latency demanding as virtual reality, but sensitive users can tell the difference in mouse response down to the same 20 milliseconds or so, making it worthwhile to apply these techniques even in applications without a VR focus. I wish people would start treating text editors that they are developing this way. As hard real time systems. Don't care much about virt…

Would you be willing to pay a recurring fee for using an editor? I have toyed with writing an editor at multiple points but have backed away because I think in the grand scheme of things its a one time sale to a pretty small market (The number of people who care enough about text editing that they would pay for a good editor when they see one)

Re: John Carmack: Latency Mitigation Strategies

#16

Post by marshray »

neverm0re wrote: post #11
modeless wrote: post #7

Earlier quoted context omitted.

Virtual Boy pretty strongly illustrated that if you can't do this perfectly, you shouldn't do it at all. Absolutely. But the Virtual Boy was clearly before its time. The hardware just wasn't ready. Within the current constraints (including budget), making a "good enough" product is clearly not feasible. I think that's clearly not true. The response from everyone who's tried the Oculus Rift has been that real VR has f…

> Specifically, they could source a higher-res, higher frame rate, lighter, lower-latency OLED display None of those are actually remotely as important as the fact you're still using your head as a dumb camera joystick, there's no ability to track eye movement and the mismatch between what you're seeing and your inner-ear pressure is going to make a number of people throw up.[1] These are fundamental problems that ha…

> mismatch between what you're seeing and your inner-ear pressure

How does your inner-ear pressure change such that it cannot be fixed with better display and rendering?

Re: John Carmack: Latency Mitigation Strategies

#17

Post by BystanderX »

untog wrote: post #9
modeless wrote: post #2

I think head-mounted-display virtual reality is a huge missed opportunity for next-gen consoles. They could have really done it right in a way that PCs can't yet, with special hardware support for low latency and stereo rendering, and a guaranteed large audience so game studios could justify applying their full budgets to AAA VR titles. It would be a huge differentiator at a time when consoles seem to be converging t…

I think VR is fundamentally broken, because you're going to try to react to things in a way that doesn't work. With a head-mounted display, the game can react as you move your head. Great. But then you'll instinctively try to walk towards something and it won't work (or you'll hit the wall). Same with picking things up, etc. It seems like it's deep in the uncanny valley of experience.

I agree, it'll certainly be uncanny.

Except, we adapt. I think Uncanny Valley will slowly shrink - Things will improve, and we'll get used to some of the oddities.

I mean, he mentions it in the article: People were used to 400ms latency and still had fun. Is there a much tighter threshold here? Sure. But I'm all for it, and I'm sure a lot of people are. Not everyone, but things improve and change.

Re: John Carmack: Latency Mitigation Strategies

#18

Post by BystanderX »

MattDL wrote: post #10
efdee wrote: post #3

I feel stupid.

Honestly I think the vast majority of people (even on HN) feel fairly stupid when you read something like that. It's an utter blessing that there are people such as Carmack in the industry.

- who are willing/eager to share their research and thoughts with the general public.

I imagine he had to push it a little to get Zenimax to allow it to be publicized, since he slipped that credit in there.

Re: John Carmack: Latency Mitigation Strategies

#19

Post by modeless »

neverm0re wrote: post #11
modeless wrote: post #7

Earlier quoted context omitted.

Virtual Boy pretty strongly illustrated that if you can't do this perfectly, you shouldn't do it at all. Absolutely. But the Virtual Boy was clearly before its time. The hardware just wasn't ready. Within the current constraints (including budget), making a "good enough" product is clearly not feasible. I think that's clearly not true. The response from everyone who's tried the Oculus Rift has been that real VR has f…

> Specifically, they could source a higher-res, higher frame rate, lighter, lower-latency OLED display None of those are actually remotely as important as the fact you're still using your head as a dumb camera joystick, there's no ability to track eye movement and the mismatch between what you're seeing and your inner-ear pressure is going to make a number of people throw up.[1] These are fundamental problems that ha…

Eye tracking would be awesome but it's not required for good VR. I fail to see how "using your head as a dumb camera joystick" is a problem; that's the whole point of VR.

Motion sickness is a real problem for some people (but not all). With low latency and thoughtful game design I think it can be mitigated. The bigger problem is the social acceptability of blocking your entire field of vision for long periods of time. I won't pretend that VR doesn't have problems, but the payoff is large enough that the problems are worth tackling.

Re: John Carmack: Latency Mitigation Strategies

#20

Post by nitrogen »

mtgx wrote: post #13
modeless wrote: post #2

I think head-mounted-display virtual reality is a huge missed opportunity for next-gen consoles. They could have really done it right in a way that PCs can't yet, with special hardware support for low latency and stereo rendering, and a guaranteed large audience so game studios could justify applying their full budgets to AAA VR titles. It would be a huge differentiator at a time when consoles seem to be converging t…

Well Oculus Rift should support everything from PC's to consoles. But I agree. Stuff like Oculus Rift is the true next-gen computing. The PS4 and next Xbox leave me pretty cold, especially when I already have a laptop that can already play all the latest games.

I think the PS4's insane memory bandwidth (8GB of memory on a 170GB/sec GDDR5 bus) makes it a very interesting contender against PCs (dual-channel DDR3 maxes out at 34GB/s).
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