Upscaling allows an application to render at a resolution lower than the resolution of the headset. The resulting images are then “stretched” to fit the resolution of the headset. The simplest upscaling technique merely interpolate the missing pixels based on the adjacent ones, usually creating “blurriness”.
The upscaling techniques included in the OpenXR Toolkit strive to produce better results through the use of additional filtering and sharpening techniques, while keeping a very low cost. Note that even with an upscaling factor set to 100% (no upscaling), some benefit can be seen from adjusting the sharpening.
In the paragraphs below, we use the term “target display resolution” to refer to the per-eye resolution exposed by the OpenXR runtime. This resolution may be the native resolution of the headset, or it may be tweaked through the use of any “custom render scale” further down the rendering chain, like when setting a custom render scale in the OpenXR Tools for Windows Mixed Reality.
There are three parameters to control upscaling:
The type of upscaling, to chose between NIS or FSR (see below). Each type of upscaling might work better for certain applications, or their effectiveness might depend on your personal preferences. Changing this setting requires the VR session to be restarted.
The upscaling factor, which represents the ratio between the target display resolution and the application rendering resolution. Changing this setting requires the VR session to be restarted.
The sharpness setting, which indicates how much sharpening the algorithm performs. This setting is adjustable in real-time, without the need to restart the VR session. The effect of the sharpening setting greatly varies between NIS and FSR.
There are two ways to specify the upscaling factor. The two methods are exactly equivalent, and you may choose which one to use at your preference:
A value above 100% represents the ratio “target display resolution over application rendering resolution”. The higher the value, the lower the application rendering resolution. For example, a value of 200% means that the application rendering resolution will be calculated to produce a target display resolution twice higher. If the target display resolution is 2200x2200 pixels, then the application will render at a resolution of 1100x1100 pixels.
A value below 100% represents the ratio “application rendering resolution over target display resolution”. This is how the upscaling factor was specified in the previous version of the NIS Scaler. The lower the value, the lower the application rendering resolution. For example, a value of 50% means that the application rendering resolution will be half of the target display resolution. If the target display resolution is 2200x2200 pixels, then the application will render at a resolution of 1100x1100 pixels.
The Anamorphic setting controls whether using a single factor in order to upscale both the horizontal and the vertical resolutions proportionaly, or using two independant upscalling factors, one per dimension.