Oculus link is the feature that allows Oculus Quest to act as a PC VR headset via a USB cable. Quest owners who own a gaming PC have access to the Oculus Rift library and SteamVR.
Oculus Link works differently from classic PC VR headsets like Oculus Rift S and Valve Index. For these headsets, when each image is rendered, it is transmitted, raw, from the GPU to the screens via DisplayPort or HDMI.
USB does not have enough bandwidth for raw video images at a resolution suitable for virtual reality, so Link works by compressing (encoding) each frame first. When the frame arrives at the quest, it is decompressed (decoded) by the Snapdragon processor. Since encoding and decoding take time, Link has higher latency than a “real” PC headset.
You don’t notice this latency when you rotate your head, because the quest distorts the decoded image in the direction of your head since the start of rendering – this is called TimeWarp. However, when you move your head or joysticks, the delay before you see this movement in the helmet may become noticeable.
One of the main methods used to reduce perceived latency in VR systems is prediction. Before each image is rendered, the system must decide which position in the virtual world to use as a perspective. As rendering takes time, the ideal position is where the user’s head will be once the rendering is finished.
Prediction algorithms, sometimes handcrafted and sometimes powered by machine learning, try to determine where your head will be after this hour. It is based on the most recent position and factors such as current acceleration and past movements.
Since Link frames must also be encoded and decoded, the prediction algorithm must look even further into the future than usual. Based on this patch note, it appears that Facebook has modified its algorithms to produce more accurate results with this longer prediction interval. Facebook is a world leader in machine learning, but it is unclear whether this is related to this change.
V18 is currently available on the public test channel. To register, go to the Beta tab in the settings of the Oculus PC application. You will see it start downloading in the Library tab.
By switching between v17 and v18, there is a small but noticeable decrease in perceived position tracking. This should be good news for Quest owners who are now using Link to access the wealth of content on Rift and SteamVR.
This story originally appeared on Uploadvr.com. Copyright 2020