Algorithms

intermediate concepts

X-Frame FPS Accelerator · Core Concepts

Downsampling Algorithms

X-Frame FPS Accelerator includes three downsampling algorithms. Each offers a different trade-off between performance gain and image quality.

Horizontal Downsampling

Resolution reduction is applied horizontally only. A quality factor of 0.5 produces a frame at Screen Width / 2 × Screen Height, which is then upscaled to full resolution.

  • Good for preserving vertical detail (UI text, HUD elements).
  • Always applied regardless of current FPS.

Quad Downsampling

Resolution reduction is applied horizontally and vertically. A quality factor of 0.5 produces a frame at Screen Width / 2 × Screen Height / 2 (25% of pixels), then upscaled.

  • Greater performance gain than Horizontal for the same quality factor.
  • Always applied regardless of current FPS.

Adaptive Downsampling (Recommended)

Works like Quad Downsampling but dynamically adjusts the resolution factor based on current FPS. You define a target FPS and a quality range; X-Frame continuously finds the best balance.

  • If FPS is above target: quality increases automatically.
  • If FPS is below target: quality decreases toward the minimum.
  • Zero impact when the device already meets performance targets.

Algorithm Comparison

AlgorithmResolution at 0.5AdaptiveBest for
HorizontalW/2 × HNoText-heavy UIs
QuadW/2 × H/2NoFixed-quality mobile
AdaptiveDynamicYesGeneral use (recommended)
URP note: When Universal Rendering Pipeline is enabled, X-Frame always uses Adaptive Downsampling internally, regardless of the selected method.

Quality Control

You always control the minimum quality factor. Set it high (0.7–0.8) to prioritize image quality, or low (0.3–0.5) to prioritize smooth FPS. X-Frame gives you the ability to support weaker devices without affecting the experience on powerful hardware.

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