Over the past year you have heard AMD talk a lot about Asynchronous Compute, and its significance has been clearly demonstrated in many DirectX® 12 and Vulkan® games, as well as VR. There were two specific features enabled by this capability that we elaborated on for AMD LiquidVR™1 Technology:
- Asynchronous Time Warp (ATW) – helps to reduce latency and prevent image judder caused by dropped frames. Oculus’ ATW solution is designed to be automatic and transparent to users as well as to developers.
- Quick Response Queue (QRQ) – tasks submitted into this special queue get preferential access to GPU resources while running asynchronously, so they can overlap with other workloads. More details can be found here.
ATW works by tracking the user’s head motion while each frame is being rendered, and re-projecting the last completed frame to the point of view of the user’s latest head position. This helps ensure that the headset always has an up-to-date frame to display, even if the system was unable to finish rendering a completely new frame in time. QRQ allows the re-projection operation to occur in parallel with graphics rendering, so it can be executed as quickly and efficiently as possible.
ATW is enabled automatically for Oculus Rift headsets and has been shown to be effective at reducing perceived latency and enabling comfortable VR experiences, however it still has some limitations. Specifically it cannot compensate for motion that occurs in the rendered scene itself, only that caused by head movements. Moving objects are just re-rendered at their last known location, which in some cases can noticeably degrade the quality of the experience.
Today we are announcing support for Asynchronous Spacewarp (ASW), which was designed by Oculus to complement ATW and enhance its effectiveness. It works by comparing previously rendered frames to detect motion between them, and using that information to extrapolate the position of scene components in the next frame. This allows re-projected frames to more accurately approximate how they would look if they had been fully rendered.
The motion detection calculations required for ASW need a considerable amount of computational power, and they must be completed within a few milliseconds just before each frame is ready to display. The latest iteration of AMD LiquidVR provides access to powerful image processing hardware in VR-capable AMD Radeon GPUs that can generate the necessary motion vectors without burdening the main graphics engine.
Combined with the existing ATW and QRQ features, ASW can enable incredibly smooth and comfortable VR experience on AMD CPUs and select “Polaris” architecture based GPUs available at an attractive price point, making VR accessible to virtually everyone. This is the latest example of how AMD and our technology partners are developing technology that helps bring premium VR to the widest possible audience.
As part of our commitment to improving the user experience in VR, as of Radeon Software Crimson ReLive Edition 17.4.1, we’re pleased to announced support for Asynchronous Spacewarp (ASW) on Radeon R9 Fury series, Radeon R9 390 series and Radeon R9 290 series graphics products. Helpful for avoiding dropped frames – particularly important on less-capable graphics cards not able to consistently achieve the full frame rates required by HMD devices when rendering especially demanding VR content – this technology can provide an overall smoother VR experience on the Oculus Rift.
In addition, starting with Radeon Software Crimson ReLive Edition 17.4.1, we now support SteamVR Asynchronous Reprojection on Radeon RX 480 and Radeon RX 470 graphics products on Microsoft Windows 10. Asynchronous Reprojection can reduce judder to provide an overall smoother and more comfortable VR experience on the HTC Vive.
Download the latest Radeon Software to discover the true power of Asynchronous Compute on Radeon graphics.
Sasa Marinkovic is Head of VR and Software Marketing for AMD. Links to third party sites are provided for convenience and unless explicitly stated, AMD is not responsible for the contents of such linked sites and no endorsement is implied.