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ValveSoftware / openvr

OpenVR SDK
http://steamvr.com
BSD 3-Clause "New" or "Revised" License
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Equivalent of "motion to photon latency"? Measuring latency incurred by sensor hardware? #249

Open echuber2 opened 8 years ago

echuber2 commented 8 years ago

In the older Oculus literature and demos (Tuscany house, etc.) there's mention of "M2P" or "motion-to-photon latency", which I believe is meant to include the duration from the instance of motion impulse, through the sensor hardware in the HMD, and all through the rendering pipeline and present until the photons are emitted from the HMD that correspond to that moment in time when the motion impulse occurred. In that case, I'm wondering if there's actually any way to get information about that part of the hardware latency through the API, or if there is a standard practice for calculating this kind of latency in terms of how OpenVR works.

As it stands, it's possible to query how long it's been since the last vsync, and the FrameTiming is filled with various trivia, but it seems like no information is recorded about when the motion/IMU data was actually registered. I guess that ideally, I wish that IMU data could be polled raw, and with a timestamp attached or something. Any thoughts on this?

echuber2 commented 8 years ago

Relevant: http://steamcommunity.com/app/358720/discussions/0/535151589887206689/#c535152511351264317

cjwidd commented 8 years ago

I am a researcher working on an interdisciplinary research team that is using Vive for our project, We would also like to know if this information is attainable through the API, or whether it must be calculated using a camera system as indicated above. Any advice from a Valve developer would be much appreciated!