VIVE Wireless Adapter and Supersampling

[Maribel_Hearn]

I've noticed choppy performance when using the wireless adapter in combination with the default supersampling value in SteamVR (SteamVR gives my system a value of 190% by default.)

In scenes with large amounts of detail that I am assuming is difficult to compress, the scene will pixelate and framerate will drop. For example, in the game "VRChat" in a public world called "Scarlett Devil Library, Voile" a large library with a huge number of books is depicted, creating a complex image. When looking across the world (See screenshot taken in desktop mode,) the image will pixelate and frames will drop with supersampling set at the default value SteamVR assigns my system. Manually reducing supersampling to 100% resolves the issue. This issue can be replicated in other scenes as well, though not to the extent of the world mentioned above. I imagine this same issue will be present in many other games that feature complex scenes such as this.

Another behavior I noticed is that after staring at the pixelated scene for several seconds as I was diagnosing the issue, is that my VIVE microphone stopped working, and did not start working again until I restarted the VIVE Wireless application. Another uneducated guess, but I believe the bandwidth limit was exceeeded, and the microphone was dropped and never reconnected after the situation stabilized.

If you are having this issue, try manually reducing supersampling if it is above 100%.

I would love to hear from a VIVE staff member on this issue, and why supersampling affects the wireless adapter in this manner. I am not familiar with how the wireless adapter compresses the data stream, and how supersampling affects that. I was under the impression that the supersampled scene is downscaled to native resolution before being sent off to the display, and in effect, before the wireless adapter. Perhaps the amount of detail in a supersampled scene exceeds the ability of the wireless adapter to compress that much detail in a timely manner. I am not educated on how it all works.

This is very unfortunate that the wireless adapter responds to supersampling in this manner, as supersampling is an amazing feature that enables a more immersive experience in VR and makes reading text, particularly distant text, much easier. As I mentioned in another thread with how the pass-through camera does not work with the wireless adapter at this time (on my system,) this is another big compromise to gain wireless.

I must also admit that VRChat is an extremely poorly optimized game from the start, and filled with user-created content that is also, generally, poorly optimized. However, the world in question in actually one of the more optimized worlds as far as GPU and CPU load goes. CPU usage when I am in a complex world in VRChat is generally confined to just a few threads, and below 75% usage, due to the total lack of meaningful multithreading in VRChat. GPU load also stays quite low, even at 190% supersampling, with power target rarely exceeing 80% and GPU clock speed generally staying ramped down as well.

My system specs:
i7 8700k @5.0GHz
16GB DDR4 @3200MHz
ASUS ROG STRIX GTX1080 @1908MHz OC
Samsung 960 PRO SSD
Windows 7 SP1

Screenshot of the scene that causes the wireless adapter to become a pixel mosaic and drop to 25FPS with supersampling turned on below...

 

[GaryMansell]

I agree - we also see lag on home built VR experiences when using a Vive Pro with the Wireless Adapter when we turn up Super Sampling.

 

I was always under the impression that Super Sampling is done on the PC and then downsized before sending to the headset. (ie there is only ever a native sized image sent to the HMD).

 

Why should this be the case?