steamvr motion smoothing – Augmented & Virtual Reality Confabulation

May 19, 2019

SteamVR Update Brings Motion Smoothing to Modern AMD Graphics Cards

Valve this week released an update to SteamVR which finally brings Motion Smoothing to AMD graphics cards, a feature which aims to maintain comfortable visuals even during performance bumps. SteamVR Motion Smoothing launched first for NVIDIA graphics cards in November 2018.

The public branch of SteamVR was updated to version 1.4.14 this week, which incorporates all prior beta updates since the last public branch update.

Among a heap of other improvements and fixes, 1.4.14 finally brings the SteamVR Motion Smoothing feature to AMD RX and Vega graphics cards. R9 and older cards are not supported. Valve also says that while the newer Radeon VII is technically supported, there’s a bug in its graphics driver which can cause Motion Smoothing to stop working, that hasn’t offered a timeline for when this might be fixed.

Motion Smoothing hit the public branch of SteamVR back in November 2018 with support for NVIDIA GPUs. The feature is a more advanced version of prior VR rendering tech which aims to keep the view inside the headset smooth and comfortable, even if the computer occasionally drops frames due to performance issues. It’s similar to Oculus’ ASW technology.

Enjoy Judder Free VR With SteamVR Motion Smoothing

It’s no secret that running virtual reality (VR) applications requires a reasonably powerful PC. While components at a certain specification level are a must, companies like Oculus and Valve are continually looking at ways of bringing that entry-level barrier down, reducing costs and therefore hopefully increasing the user base. Oculus was first with Asynchronous Spacewarp and then SteamVR released Asynchronous Reprojection allowing lower spec PC’s to run VR. Today, SteamVR has improved upon Asynchronous Reprojection with its new feature, SteamVR Motion Smoothing.

HTC Vive Pro Just like before SteamVR Motion Smoothing is a process to help more PC’s and more players join the VR world through clever reduction of judder. Judder on a standard TV or monitor can be annoying, but in VR – for those yet to experience it – judder can be nauseating to the point where you never want to try VR again.

Where SteamVR’s Asynchronous Reprojection reduced judder by showing the last frame again (altered to fit the player’s movement), Motion Smoothing works slightly differently. Explaining in a blog posting: “When SteamVR sees that an application isn’t going to make framerate (i.e. start dropping frames), Motion Smoothing kicks in. It looks at the last two delivered frames, estimates motion and animation, and extrapolates a new frame. Synthesizing new frames keeps the current application at full framerate, advances motion forward, and avoids judder.”

That allows a player using an HTC Vive or HTC Vive Pro (the feature doesn’t work on Oculus Rift or Windows Mixed Reality headsets) to still enjoy the VR experience at the full 90 Hz framerate while the application is only rendering 1 out of 2 frames. The process can even go a stage further synthesizing 2 frames for every 1 frame to keep performance the same.

Steam VR / SteamVR SteamVR Motion Smoothing has the double benefit that lower-end GPU’s can now render VR applications, with higher-end GPU’s now able to up the resolution even further for improved visuals.

And you don’t even need to switch the feature on. So long as you’re running a HTC Vive headset with Windows 10 and an NVIDIA GPU then SteamVR Motion Smoothing will automatically kick in when needed. To alter the options head to ‘Settings > Video’ or ‘Settings > Applications’. For more updates to SteamVR, keep reading VRFocus.

October 18, 2018

SteamVR Gets Motion Smoothing, an ASW-like Feature to Help VR Apps Run Better

Valve today introduced Motion Smoothing to SteamVR in beta. Similar to Oculus’ Asynchronous Spacewarp (ASW), the feature uses previous frames to synthesize new frames on the fly, allowing VR applications to continue to run smoothly and comfortably even when dropping frames.

PC VR headset demand relatively powerful gaming hardware because games need to be rendered at very high resolution, in 3D, and at high framerates. Doing all of that with very low latency and high consistency can be a challenge even for powerful gaming computers which may occasionally fail to render the next frame by the time the headset needs it, leading to a dropped frame. Without any intervention, a dropped frame will cause the headset will re-display the previous frame, which means the view in the headset looks like the world has momentarily attached itself to the head of the user. This can be very discomforting in VR, especially if several frames are dropped in a row.

One way of dealing with this issue is by using reprojection (timewarp, by Oculus’ naming), which, in the case of a dropped frame, shows the previous frame but reoritents it based on the user’s latest head rotation. That means what while anything moving in the game world will be motionless, at least the world still appears to respond to the player’s head movements, thereby avoiding discomfort.

But, this doesn’t account for positional head movement, and it still has the problem of the game being frozen during dropped frames, which means objects in motion in the game world will stutter or freeze.

Like Oculus with ASW, Valve is implementing an additional layer of performance protection for applications prone to dropping frames, one which can also account for moving objects and characters within the application.

Introduced today in beta by Valve’s Alex Vlachos, Motion Smoothing in SteamVR synthesizes entirely new frames to use in the place of dropped frames. It does so by looking at the last two frames, estimating what the next frame should look like, then sending the synthesized frame to the display instead of an entirely new frame. Presently Motion Smoothing is only available on NVIDIA GPUs and systems running Windows 10, though Valve says that AMD support is in the works. Motion Smoothing only works with the Vive, Vive Pro, and other native OpenVR headsets as other headsets (like the Rift and Windows VR) have their own approach to dealing with dropped frames.

Motion Smoothing kicks in automatically when SteamVR detects than an application is dropping frames. Like ASW, it cuts the application’s usual 90 FPS framerate down to 45, and generates a synthetic frame every other frame. That means that the user sees smooth 90 FPS motion in the headset, but the application has twice as much time to deliver new frames. Valve says that Motion Smoothing can be used even more aggressively if needed, synthesizing two frames or even three frames for every one real frame delivered by the application. You’ll also be able to disable it if you don’t want to use it.

Reducing or removing the requirement of VR applications to deliver consistent 90 FPS would make it viable for lower end hardware to run VR applications without major performance issues, and for higher-end hardware to run at higher resolutions or with greater graphical effects without suffering major performance issues. Combined with the Auto Resolution feature of SteamVR (which automatically optimizes the application’s render resolution to match the system’s GPU performance), Motion Smoothing could expand the range of hardware which can acceptably run VR experiences.

Valve’s Alex Vlachos tells Road to VR that Motion Smoothing is similar to Oculus’ ASW, but not identical.

“We feed the last two frames from the application to the GPU’s video encode chip to generate motion vectors (which are very rough), then [Valve and Oculus each have their own] methods for filtering those vector fields and applying them to the most recent application frame to generate a new frame,” he said. “So ASW, SteamVR Motion Smoothing, and WMR Motion Reprojection are just different implementations of the same high-level tech.”

Oculus recently introduced ASW 2.0, which aims to use depth information to improve the accuracy of synthesized frames. For Valve’s part, the company may make use of depth information at some point, but are mainly seeking generalized solutions.

“We have different approaches to reduce repeating pattern artifacts, and we have a few other methods internally that we may ship soon,” Vlachos said. “We are currently focusing our efforts on solutions [to synthesized frame artifacts] that apply to all applications, because as higher resolution headsets hit the market, our goal is to ensure customers can get as close to native resolution as possible with a wide range of GPUs.”