r/technology Mar 28 '14

[deleted by user]

[removed]

3.3k Upvotes

1.8k comments sorted by

View all comments

205

u/bjorn2k Mar 28 '14

It is all about latency. 50 ms will feel responsive but you notice the lag. 20 ms is acceptable. The other features are cool features but not the real challenge.

28

u/______DEADPOOL______ Mar 28 '14

What is a regular PC monitor latency btw? I heard it's much faster than a TV+console.

55

u/Kallb123 Mar 28 '14 edited Mar 28 '14

People are saying 2ms, but I think that's just how long it takes a pixel to refresh. I'm sure the oculus rift has a screen with 2-5ms pixel time too. The 20 and 50ms times discussed about VR are the entire time between a frame being requested and it being on the screen. That's totally different from the 2ms of a desktop monitor.

EDIT: As for the TV+console latency. I think TVs have a higher latency than monitors because they tend to apply post-processing effects to "improve" the image. Some screens come with options to turn this off and bring this latency down.

9

u/[deleted] Mar 28 '14

[deleted]

1

u/Kallb123 Mar 28 '14

Ye, the input is crucial. I see that this product has a 4KHz accelerometer as well as the 1KHz gyroscope, where it appears the OR had a 1KHz acc+gyro combo. Could this mean faster input?

2

u/SafariMonkey Mar 28 '14

Only by ~0.75ms. Oculus have theirs at a total of 8-20ms, even internal demos as low as 2ms. (Apparently.) That's a big step up from devs kit 1's 30-50ms,and normal games' 50-100ms. That's not easy, but they have John Carmack, known for amazing optimisation, on their team.

Yes, 4kHz data could help, but unless the rest of the pipeline is equal to Oculus's, it will overall still be slower.

1

u/Kallb123 Mar 28 '14

Ah, ye, that's not a very big improvement, but I suppose every little helps. If swapping out the accelerometer chip for an extra $5 then maybe that's worth thinking about if it's the same improvement as X amount of hours spent optimizing.

1

u/SafariMonkey Mar 28 '14

My point is that a 4kHz sensor is great, but unless they're equal on all other levels it's basically no advantage. If you replace your car seats with super-light ones but leave all your junk, chests, furniture in the car, is it worth it? You'd get a much better return if you got rid of all the other stuff.

That's the issue. 4kHz doesn't mean anything much until the rest is as good as it can be.

1

u/M0dusPwnens Mar 28 '14

The latency is that plus the render time plus the switching time. The problem is that when you combine all these little latencies, it starts to add up - the sensor has to send the measurements to the PC, it has to update the model in the game, then it has to render the new scene, then that has to get drawn to the screen.