Forum Discussion
Rift latency
Has anyone else measured the Rift's end-to-end latency? By this I mean movement time to photons off the screen time. I am getting numbers around 25-35ms measured using the official Unity plugin. Can a...
"doktorvr" wrote:
Yes I am using photo diodes input to my sound card. One diode detects a gradient (black to white) in front of the Rift and the other is positioned inside the Rift where a similar gradient changes with tracker rotation. I analyse the phase difference in the resulting gradient changes. The full method is published here: http://dl.acm.org/citation.cfm?id=1971108
Nice! That abstract pretty much describes it all, and simple and inexpensive too! Photodiodes should be much faster than using a video camera (even if high speed). I like it!
:D
At 60Hz framerate, you should see about 16.7ms of jitter in your measurements, depending on what scanline you begin your measurement. You really need to average many measurements to establish a statistically significant mean value (or range), or you need to take time since VSYNC into account on your sound phase measurements. Otherwise the majority of your measured latency is just "noise".