AMD Details FidelityFX Super Resolution 2.0

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Higher quality but lower performance

AMD presented it's FidelityFX Super Resolution 2.0 algorithm at GDC 2022, which we'll abbreviate to FSR2 going forward. As GDC caters to game developers, and with FSR and FSR2 being open source algorithms, AMD went into the nitty gritty of how everything works, and the choices and optimizations that were made. It also went into some of the benefits and difficulties of FSR 1.0, and how things will change with FSR2.

From a high level, FSR2 is designed to offer significant quality improvements over FSR1. It's an all-new algorithm, not built on the existing FSR work, which means integrating the new API will require reworking some of the code. AMD also expects FSR2 to be more demanding on the hardware side of things, part of the compromise needed to improve image quality. It's still an open API, designed to work on GPUs from AMD's competitors, including older generation GPUs, but the performance gains may be limited with low-end hardware.

FSR 1.0 was a spatial upscaling algorithm, designed for high performance and ease of integration into games. There were shortcomings with this approach. For example, FSR 1.0 requires a high-quality anti-aliased source image, which means if a game didn't have anti-aliasing already, it needed to implement that before it could use FSR. The quality of the upscaling was also dependent on the AA, so a poor quality AA would produce inferior upscaled results. It also didn't handle lower resolutions as well, as the lack of information in the source frame could result in shimmering, poor edge reconstruction, and other artifacts.

FSR2 switches to a temporal upscaling solution, and the input requirements are quite a bit more complex than with FSR. Instead of just a frame, FSR2 takes the scene color (i.e., the final rendered frame), scene depth buffer, and a motion vector buffer. This is similar to DLSS. From these, it produces a higher quality upscaled output. Unlike DLSS, however, no machine learning hardware is required or utilized.

As far as integration goes, FSR2 now takes an aliased image and produces anti-aliased results. Games that already implement DLSS or other temporal upscaling solutions should be able to easily integrate FSR2. FSR2 also supports dynamic resolution scaling (DRS), so it can replace other dynamic upscaling solutions.

AMD has also made some adjustments with the various upscaling modes. Previously, FSR1 had four presets: Ultra Quality, Quality, Balanced, and Performance. With FSR2, AMD has aligned its mode names with DLSS, so there will be Quality, Balanced, Performance, and an optional Ultra Performance mode. The input resolutions are unchanged, as far as we can tell, so Quality at 4K still upscales from 2560x1440 to 3840x2160 (1.5X upscaling factor in both dimensions), Balanced uses a 1.7X upscaling factor, Performance uses 2X, and Ultra Performance (mostly for extreme resolutions like 8K) uses a 3X upscaling factor.

FSR2 is currently in "beta" and further refinements are being made. AMD will put the full slide deck and video online sometime today, or in the near future, and it's slated to leave beta by June 2022. You can see a preview of FSR2 running in Deathloop in the video below.
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