5 ms·

For anyone interested in why VirtualLink didn't go anywhere, one of the limiting factors was that USB 3 and above is entirely separate from USB 2 and below. No

by wolrah 3y ago

For anyone interested in why VirtualLink didn't go anywhere, one of the limiting factors was that USB 3 and above is entirely separate from USB 2 and below. Normal USB-C DP Alt Mode delivers either four lanes of DP and USB 2 or two lanes of DP and both varieties of USB. VirtualLink takes the 4xDP variant and upgrades the USB pairs to support 3.x modes, but that means if you plugged a USB 2 device in to the headset itself there'd be nowhere to route that traffic. A chip was developed to bridge the gap and allow USB 2 devices to connect to the USB 3 bus, but there were quirks and it ended up not being ready in time to be useful to the VR market. Valve eventually cancelled their adapter plans and that was the end of it. This Hackaday article has a lot of useful links including an open source breakout board design for the chip in question: https://hackaday.com/2022/03/07/a-chip-to-address-the-fundamental-usb-3-0-deficiency/ https://hackaday.com/2022/03/07/a-chip-to-address-the-fundam...

jsheard 3y ago
I suspect the rise of good-enough wireless PCVR over commodity WiFi hardware didn't help matters either - being able to tether a headset over a single USB-C cable is mildly convenient but nowhere near as convenient as having no cable at all. Oculus and Pico both went down that route and it looks like Valve are also going to with their next headset.
- snvzz 3y ago
  >nowhere near as convenient as having no cable at all. AIUI the tech just isn't there for this. There's latency and packet loss to deal with, whenever there's a radio in the path.
  - jsheard 3y ago
    The tech has been there for years, if you look at discussions of using the Quest for PCVR the default recommendation is to use WiFi streaming rather than the tethered USB mode. The trick is that the reprojection still runs on the headset itself so the critical part for avoiding motion sickness has minimal latency regardless of the signal quality.
    - wolrah 3y ago
      As an early adopter of the Vive (didn't preorder but bought within the first few weeks) who also has a Quest 2, the "good-enough" part of your previous post is definitely open to interpretation. I will say I agree with using it wireless being the default recommendation, but there's a reason people still buy fiber optic USB-C cables. If you have a good WiFi setup, which a lot of people do not (and a lot of people who think they should have good WiFi because they spent a lot of money on it still don't because they don't understand what they bought), it's perfectly fine for most games that don't depend on tight timing, but you can still tell when playing Beat Saber or similar. I noticed it most as input jank on the controllers, both compared to the Vive and native Quest apps. IMO the right answer is a Quest-like standalone handset with a VirtualLink style input to allow uncompressed signals with predictable latency to flow between the two. Best of both worlds. Wired Quest now is effectively just using the USB port as a network interface rather than a display.
  - crooked-v 3y ago
    I've been using Virtual Desktop (vrdesktop.net) for a while now and it works great. With some judicious use of its resolution scaling options and a physically nearby Wifi 6 router it's pretty easy to get latency down to 30-40ms. The only real trouble spots I still run into are games that have wildly unoptimized elements like VRChat.
    - snvzz 3y ago
      30-40ms is an eternity for VR. I get a headache just from thinking about it.
  - wkat4242 3y ago
    It's cool to hear what I use every day is tech that isn't here yet :) I use my Quesr 2 with my PC (4090) all the time and it's great. The lag is minimal and I have no motion sickness. I use a dedicated wifi 6 ap with its own SSID though because I noticed multiple devices on the same AP causes stuttering. Probably from switching between higher and lower modulations. But this way it works perfectly. I hope the Quest 3 will get wifi 6E for more free channels

by wolrah 3y ago

jsheard 3y ago

I suspect the rise of good-enough wireless PCVR over commodity WiFi hardware didn't help matters either - being able to tether a headset over a single USB-C cable is mildly convenient but nowhere near as convenient as having no cable at all. Oculus and Pico both went down that route and it looks like Valve are also going to with their next headset.

snvzz 3y ago
>nowhere near as convenient as having no cable at all. AIUI the tech just isn't there for this. There's latency and packet loss to deal with, whenever there's a radio in the path.
- jsheard 3y ago
  The tech has been there for years, if you look at discussions of using the Quest for PCVR the default recommendation is to use WiFi streaming rather than the tethered USB mode. The trick is that the reprojection still runs on the headset itself so the critical part for avoiding motion sickness has minimal latency regardless of the signal quality.
  - wolrah 3y ago
    As an early adopter of the Vive (didn't preorder but bought within the first few weeks) who also has a Quest 2, the "good-enough" part of your previous post is definitely open to interpretation. I will say I agree with using it wireless being the default recommendation, but there's a reason people still buy fiber optic USB-C cables. If you have a good WiFi setup, which a lot of people do not (and a lot of people who think they should have good WiFi because they spent a lot of money on it still don't because they don't understand what they bought), it's perfectly fine for most games that don't depend on tight timing, but you can still tell when playing Beat Saber or similar. I noticed it most as input jank on the controllers, both compared to the Vive and native Quest apps. IMO the right answer is a Quest-like standalone handset with a VirtualLink style input to allow uncompressed signals with predictable latency to flow between the two. Best of both worlds. Wired Quest now is effectively just using the USB port as a network interface rather than a display.
- crooked-v 3y ago
  I've been using Virtual Desktop (vrdesktop.net) for a while now and it works great. With some judicious use of its resolution scaling options and a physically nearby Wifi 6 router it's pretty easy to get latency down to 30-40ms. The only real trouble spots I still run into are games that have wildly unoptimized elements like VRChat.
  - snvzz 3y ago
    30-40ms is an eternity for VR. I get a headache just from thinking about it.
- wkat4242 3y ago
  It's cool to hear what I use every day is tech that isn't here yet :) I use my Quesr 2 with my PC (4090) all the time and it's great. The lag is minimal and I have no motion sickness. I use a dedicated wifi 6 ap with its own SSID though because I noticed multiple devices on the same AP causes stuttering. Probably from switching between higher and lower modulations. But this way it works perfectly. I hope the Quest 3 will get wifi 6E for more free channels