Playing PCVR on VR Headsets
Standalone chips have limited processing power, so we often connect our headsets to our computers, which have much more processing horsepower to push out more, higher quality frames.
There are several ways this can be accomplished.
"Native" PCVR (DisplayPort, HDMI)
Generally the most straight forward. You connect your headset to a USB port and to a video output of your GPU by cable. This is always the case with PCVR headsets (IE have no standalone capabilities), and is the case for A FEW stand alone headsets.
Note that a input video / USB C port is not enough, there needs to be specific switching hardware in a stand alone headset to run in native mode (IE having the PC GPU push to the VR display panels directly). Ergo, even though some stand alone headsets even do displayport over USB C (or more typically have a separate port), the reason they can do native PCVR is because of the additional switching hardware they have. However, this is pretty uncommon.
+ Direct Video out has no compression artifacting (Or minimal, in the case that DSC needs to be used in some cases)
+ Tends to be rather reliable (this does depend on the software)
+ No further processing is required. Pixels are spit out right from the GPU to the headset, which saves on performance
+ Lowest latency
- Stand alone headsets do not support this unless they specifically have hardware for this, which they usually don't due to cost reasons.
- Always wired
- Your PC Needs to have a direct DisplayPort (or HDMI on older headsets) out. This is often not the case for laptops which either lack the port entirely, or have the physical port, but is actually connected to an iGPU making it unusable for VR, regardless of the performance of any dedicated GPU inside!
Encoded (wireless / USB) PCVR
Most stand alone headsets do not have the hardware to take in DisplayPort connections. Instead, they make use of their onboard Qualcomm SOC to view video feed that has been generated from a PC.
Its important to the difference here. In this case, while the PC GPU still builds the frame, instead of merely outputting it to a cable, the PC then has to encode the frames into a video codec format (such as H264, or H265) that can then be streamed over a USB or network connection to the headset, which can then decode the stream for the user to see. While this does open up some various possibilities (such as being able to stream over WiFi, thus removing the need for a cable tethering the headset), these extra steps add complexity, latency, and processing demands on the host PC. Further more, encoding a stream cannot be done at full quality,
+ Is the only option on a majority of stand alone headsets, to allow playing of PCVR content on them
+ Can be done over WiFi (or Wigig) for wireless play (more info below)
+ Can also be done over USB (or in some cases Ethernet cable) if wireless is not preferred
+ Often the only way to use a laptop for PCVR (if it does not have a DisplayPort directly hooked up to a dedicated GPU)
- As typically PC must now encode all frames, processing load increases, which may decrease overall game performance
- Latency added due to having to encode and decode the video stream
- Encoding leads to compression artifacts, which decreases image quality
- Software setup can often be a bit more complex
Methods of streaming encoded PCVR
There are different methods of getting the encoded data from the PC over to the headset. Please do research to see what your headset supports.
WiFi
The most common wireless standard used for streamed PCVR. How this works is that your PC is connected to a wireless WiFi router that your headset connects to, and through that router the headset over WiFi connects to the PC. While this works for many people, you need to ensure that your router is capable, that your air space does not have too much wireless interference, and that your headset has a strong connection to the router (typically should be in the same room). Keep in mind these variables affect the maximum throughput your can send to your headset, which affects image quality.
USB
Often used in cases where you do not mind being tethered, or where WiFi is not feasible in your environment. Some headsets (notably Meta Headsets) have software that can stream VR directly over USB. This leads to a far more stable data connection, assuming the USB port itself is capable of this. Unfortunately, only a small number of streaming applications support this.
Ethernet over USB
Some headsets allow connecting a USB to Ethernet dongle to the headset, and then you can connect an Ethernet cable from the headset to a router, which is accessible to a PC. This lets use the same setup / software as described in the above WiFi section, however without having to worry about wireless interference, meaning considerably better bandwidth and lower latency.
WiGig
An uncommon wireless standard that operates at a much higher bandwidth. This allows for wireless streaming far better than WiFi and with better latency. However, this typically requires additional expensive hardware, and is generally uncommon. Furthermore, WiGig signals can easliy be blocked physically, to the point that it essentially needs to be directly in the Users room without any obstructions between the transmitters and the receiver.
It is important to note that standards like Vive's HTC wireless Wigig system make use of CPU encoding, which does still penalize system performance as above. However some setup, such as the old TPCast streamer setup had an external encoder box that was fed video directly via video cable from the GPU, meaning there is no performance impact whatsoever.
However, this standard is generally not commonly used these days.