3 ms·

I feel like the Quest could be very light if they took the Apple approach and moved the battery and computer to a pocket box. Even before any of these headsets

I feel like the Quest could be very light if they took the Apple approach and moved the battery and computer to a pocket box. Even before any of these headsets existed I imagined most of them being that way.

charcircuit 3y ago
That would need quite the cable to support 6 camera video feeds, 2 display video feeds, 2 audio feeds, and some other control data in addition to power.
- geoelectric 3y ago
  Would it? How much total throughput and power would that be, vs a skinny USB-C PD 3.2 Gen 2x2 cable that can carry a 100W or more along with 20 Gbps of data? How about 2 or 3 of them in a wrapper? The Quest can be a PCVR headset with a 3.2 Gen 1 cable, ie 5 Gbps. How different is this? I’m pretty sure outboarding most of the hardware that’s not speaker, camera, or screen is plenty doable. It just blows Meta’s selling point of making it a self-contained device. I’d probably prefer it though, especially if I could attach the outboard module to the back of the head strap as a counterweight.
  - charcircuit 3y ago
    >How different is this? Hardware decoding / encoding all of those video streams requires a lot of processing power on both ends, adds 10s of ms of latency, and makes the video quality worse.
    - Dylan16807 3y ago
      Not video encoding, raw-ish signals. Let's say DSC is allowed, which costs microseconds and is basically invisible, and can compress down to about 8 bits per pixel. That USB cable can transmit 20Gbps in each direction. The display needs to do 23 million pixels 90 times a second, and at 8 bits per pixel that's about 17Gbps. The video cameras going the other way are 13 million pixels for the main cameras plus some amount more for the 6 tracking cameras and the other sensors. And those main cameras are outputting 8 bits per pixel before any compression is applied. It's a tight fit at that bitrate, but we can upgrade to USB4 and get 40Gbps in each direction. That leaves plenty of room for everything, and makes sure there's headroom for HDR and 100Hz and whatnot. It works out.

charcircuit 3y ago

That would need quite the cable to support 6 camera video feeds, 2 display video feeds, 2 audio feeds, and some other control data in addition to power.

geoelectric 3y ago
Would it? How much total throughput and power would that be, vs a skinny USB-C PD 3.2 Gen 2x2 cable that can carry a 100W or more along with 20 Gbps of data? How about 2 or 3 of them in a wrapper? The Quest can be a PCVR headset with a 3.2 Gen 1 cable, ie 5 Gbps. How different is this? I’m pretty sure outboarding most of the hardware that’s not speaker, camera, or screen is plenty doable. It just blows Meta’s selling point of making it a self-contained device. I’d probably prefer it though, especially if I could attach the outboard module to the back of the head strap as a counterweight.
- charcircuit 3y ago
  >How different is this? Hardware decoding / encoding all of those video streams requires a lot of processing power on both ends, adds 10s of ms of latency, and makes the video quality worse.
  - Dylan16807 3y ago
    Not video encoding, raw-ish signals. Let's say DSC is allowed, which costs microseconds and is basically invisible, and can compress down to about 8 bits per pixel. That USB cable can transmit 20Gbps in each direction. The display needs to do 23 million pixels 90 times a second, and at 8 bits per pixel that's about 17Gbps. The video cameras going the other way are 13 million pixels for the main cameras plus some amount more for the 6 tracking cameras and the other sensors. And those main cameras are outputting 8 bits per pixel before any compression is applied. It's a tight fit at that bitrate, but we can upgrade to USB4 and get 40Gbps in each direction. That leaves plenty of room for everything, and makes sure there's headroom for HDR and 100Hz and whatnot. It works out.