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Valve: Virtual Reality requires unfeasibly low latency

Wednesday, 2nd January 2013 05:12 GMT By Brenna Hillier

According to Valve engineer Michael Abrash, virtual reality gaming is up against a serious hardware limitation, and need a breakthrough moment before it can ever come into its own.

In a lengthy post on the Valve blog, Abrash explained that current hardware latency – the time it takes for what your device is doing to be displayed – is a massive stumbling block.

“Games generally have latency from mouse movement to screen update of 50 ms or higher (sometimes much higher), although I’ve seen numbers as low as about 30 ms for graphically simple games running with tearing (that is, with vsync off). In contrast, I can tell you from personal experience that more than 20 ms is too much for VR and especially AR, but research indicates that 15 ms might be the threshold, or even 7 ms,” he said.

Abrash goes into detail as to why hardware and software engineers are as yet unable to improve latency beyond its current levels, concluding that virtual reality must wait on technological advances.

“There is no way to get low enough display latency out of existing hardware that also has high enough resolution, low enough cost, appropriate image size, compact enough form factor and low enough weight, and suitable pixel quality for consumer-scale AR/VR,” he claimed.

“Someone has to step up and change the hardware rules to bring display latency down. It’s eminently doable, and it will happen – the question is when, and by whom. It’s my hope that if the VR market takes off in the wake of the [Oculus] Rift’s launch, the day when display latency comes down will be near at hand.”

Valve’s hardware teams are said to be looking at VR tech and working on wearable computing devices in addition to other top-secret projects, making a final note of Abrash’s blog – a call for clever VR fans to join the fun – all the more compelling.

Thanks, Kotaku.

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9 Comments

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  1. Stardog

    I use a USB keyboard and I have to put the ASIO4ALL driver latency down to about 10ms to get a 1:1 feel. If it’s 15-20ms+ it’ll feel like there’s lag/delay and it’s impossible to play anything complex.

    #1 2 years ago
  2. G1GAHURTZ

    I don’t believe that any human being can tell the difference between a 10ms delay and a 15ms one.

    It takes you longer than that to do a mouse click.

    #2 2 years ago
  3. adumicic

    I don’t understand his logic there. The human eye is only capable of recognizing ~60fps, therefore there is a16.6ms lag in just drawing the frame to the screen (assuming there is zero additional lag). Most console games work on 30fps or ~33ms lag. Why exactly would, what is effectively input lag, benefit from such extremes?

    #3 2 years ago
  4. Kabby

    You gave no idea what you are talking about.

    “The human eye is only capable of recognizing ~60fps.” Laughable.

    #4 2 years ago
  5. sebbie16

    The human eye (truly its the brain) is actually capable of ~72fps, but that is for the average person.

    #5 2 years ago
  6. freedoms_stain

    @3, Gabe is talking input lag and you’re talking display lag for one thing.

    Console games run at 50ms+ input lag at 60fps and 100ms+ at 30fps.

    He’s saying that these levels of input lag break the immersion of VR.

    edit: I’d also say that we have a bad headline here. VR doesn’t require infeasibly low latency, the article even quotes the part where they discuss how it can be achieved, it’s (apparently) impossible on modern hardware, but that’s not the same as being infeasible in general. Better headline would be “VR infeasible on existing hardware due to latency” or similar.

    #6 2 years ago
  7. xxJPRACERxx

    Like #1 I play keyboard too and just like him, if the input delay is more than 10ms it’s unplayable.

    And the thing about humans unable to detect more than “xx” fps is pure crap. I remember when having a 150Hz refresh rate crt monitor to be able to distinguish between 30-60-120 fps easily. And the Air Force did some experiments about this and it’s possible to see more than 200+ fps. It really depend on the individual. One of my friend can’t see the difference between 30 and 60 fps. It’s exactly like hearing. The accepted range is 20-20000Hz but majority of people can’t hear above 16k.

    It’s the same thing for all the other senses. We can generalize and do an average but each individual have different sensitivity.

    #7 2 years ago
  8. manamana

    Argh! What a letdown. And here I was, with high hopes on the Oculus Rift, to finally dive into cyberspace just like in Neuromancer. Oh well, maybe Pong will do fine …

    #8 2 years ago
  9. fuchikoma

    Aren’t these the guys who argued things like that their engine would never run on a 360 or PS3? Or that those were just fads to begin with? They seem rather shortsighted at the best of times.

    So… how exactly will this latency prevent people from using VR? By delaying reaction to turning your head, causing disorientation? But that’s not something network latency should affect anyway – you stream coordinate and animation data for objects and render your environment on local hardware. For well over a decade, this has not been a problem for people playing games online – you can hang out, you can fight, you can gesture, etc. The lag only makes this problematic when it is extreme and stops players from moving at all, or causes sequence-of-events conflicts on who shot whom first.

    VR is oldschool 90s tech now. AR is on phones, 3DS, Vita, etc. He’s predicting that we don’t have the technology to implement seriously old technology that’s been around for years. If that stands as an impediment, then you’re looking at the design problem the entirely wrong way. Valve never ceases to issue amusing and bizarre statements.

    #9 2 years ago