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DeLorean: Using Speculation to Enable Low-Latency Interaction for Cloud Gaming

research.microsoft.com

41–49 of 49 posts

Re: DeLorean: Using Speculation to Enable Low-Latency Interaction for Cloud Gaming

#41
post #14

I'm really confused by the Android bashing in the introduction of the article. > platform compatibility headaches and per-platform performance tuning [35, 30, 24]. That seems a bit biased, doesn't it?

Did you miss that this article was published by Microsoft Research?

Re: DeLorean: Using Speculation to Enable Low-Latency Interaction for Cloud Gaming

#42
post #38

One of the current annoyances of the oculus rift is that it requires a cable that restricts freedom of movement... I'd bet dollars to donuts a big part of the Oculus development effort right now is going specifically towards these kinds of "prediction" algos so that a more low-powered PC with a battery can reside in the helmet, which can communicate with a custom low-latency wireless network to a "base station" that…

> it requires a cable that restricts freedom of movement.

I don't see how this matters at all. If a cable doesn't restrict movement, surely a table, chair, wall, mountain, lake, ocean, cliff will restrict your movement. You can't emulate infinite environments when stuck in the physical world.

Re: DeLorean: Using Speculation to Enable Low-Latency Interaction for Cloud Gaming

#43
post #38

One of the current annoyances of the oculus rift is that it requires a cable that restricts freedom of movement... I'd bet dollars to donuts a big part of the Oculus development effort right now is going specifically towards these kinds of "prediction" algos so that a more low-powered PC with a battery can reside in the helmet, which can communicate with a custom low-latency wireless network to a "base station" that…

A few times John Carmack has mentioned that they are working with Android. I think they've given up wireless networks and are simply waiting for the hardware to shrink to the point where you can embed the computer in the Rift.

The new rift literally uses the complete front panel from a Galaxy Note III. Complete with (unused) touch sensors and connectors.

https://www.ifixit.com/Teardown/Oculus+Rift+Development+Kit+...

Re: DeLorean: Using Speculation to Enable Low-Latency Interaction for Cloud Gaming

#44

Earlier quoted context omitted.

A few times John Carmack has mentioned that they are working with Android. I think they've given up wireless networks and are simply waiting for the hardware to shrink to the point where you can embed the computer in the Rift.

The new rift literally uses the complete front panel from a Galaxy Note III. Complete with (unused) touch sensors and connectors. https://www.ifixit.com/Teardown/Oculus+Rift+Development+Kit+...

I was specifically talking about GPU/SoCs on the Rift rather than connecting it to a PC.

Re: DeLorean: Using Speculation to Enable Low-Latency Interaction for Cloud Gaming

#46
post #22

There are some games this will simply not work for, like fighting games, where even the delay caused by the LCD rendering each frame is noticeable. The ADC in the LCD is either too slow or has too much processing happening. Many hardcore fighting game fans prefer CRTs due to this. There is no cure for latency. The network is physical. Instead of trying to abstract it away in a library and assume lag doesn't exist, it…

Assuming infinite bandwidth and rendering speed: It sounds like, for a connection of latency L, at time T-2L, the server sends to the client multiple fully rendered frames, each representing the render state for time T for every possible user input that could occur between T-2L and T. The client receives these frames at time T-L, while sending a user input state at T-L which the server will use for a future packs of…

It's very similar to branch prediction in modern cpu architectures. Branches are expensive, so both sides are executed. It is a good idea, and I'm wrong for my remark equating any of this to webforms.

I believe we have a lot we could do to make latency lower, and effort should be focused there. Branch prediction would not be necessary if branching were cheap. This latency prediction system would not be necessary either if latency was low, but it's not. Our hardware sucks. All of the layers of software suck. OculusVR is a testament to how much room for improvement there is in regards to latency.

Re: DeLorean: Using Speculation to Enable Low-Latency Interaction for Cloud Gaming

#48
post #2

For those who want to try it out, some binaries and videos are found here: https://onedrive.live.com/?cid=611c3830c430d4e3&id=611C3830C... The user perception results are very impressive - round trip times of 250ms were not significantly noticeably different from the control fat client system.

It's gone, do anyone have a copy?

Re: DeLorean: Using Speculation to Enable Low-Latency Interaction for Cloud Gaming

#49
post #38

One of the current annoyances of the oculus rift is that it requires a cable that restricts freedom of movement... I'd bet dollars to donuts a big part of the Oculus development effort right now is going specifically towards these kinds of "prediction" algos so that a more low-powered PC with a battery can reside in the helmet, which can communicate with a custom low-latency wireless network to a "base station" that…

> it requires a cable that restricts freedom of movement. I don't see how this matters at all. If a cable doesn't restrict movement, surely a table, chair, wall, mountain, lake, ocean, cliff will restrict your movement. You can't emulate infinite environments when stuck in the physical world.

I'm actually working on figuring out user experience principles for VR. I have a Google Cardboard-style rig that I use with my Galaxy Note 3.

From my own experience, working with a keyboard at a desk doesn't really work well, for various reasons. For one, it's pretty restricting to the movement, and trying to scale the tracking to compensate so you can view a full 360 degrees in a shorter head-swing is both still limiting because you can't perform multiple rotations, and is still extremely disorienting. For another, having a physical sensation of a fixed object that isn't reflected in the visual display also breaks immersion. Also, if you have you move your hands off of the keyboard at all (like, to adjust the display on your face), it's really hard to find it again.

There is currently no good way to do user input in VR. About the best experience I've had so far was standing up, using a bluetooth gamepad.

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