artifact types: --------------------------------------------------------------------- ringing wave or noise like patterns around sharp edges bad: sinc, lanczos (with high filter length) acceptable: lanczos (with low filter length), cubic, spline ok: area, (fast)blinear, gauss, point blur loss of detail / high frequency bad: gauss with high variance acceptable: (fast)bilinear, area ok: others aliasing (only downscale) straight lines look like staircases areas of high detail look worse regular patterns turn into a funny looking mess (moire patterns) bad: fast bilinear, point, gauss with low variance acceptable: area ok: others blocky (upscale only) looks like the image is made of rectangular blocks like a mosaic bad: point ok: others recommendations: (based upon my personal opinion many ppl might disagree ...) --------------------------------------------------------------------- the recommended scalers for upscaling: fast_bilinear, point if speed is important cubic, spline, lanczos if quality is important the recommended scalers for downscaling: fast_bilinear, point if speed is important gauss, bilinear if quality is important cubic, spline, lanczos if a sharper picture is important note: when encoding at a limited amount of bits (not constant quantizer) then a slightly blurred input might look better after decoding than a slightly sharpened one, especially for lower bitrates sws numbers / names / artifact types ------------------------------------------------------------------------- r ringing b blurry a aliasing (downscale only) m mosaic (blocky) (upscale only) -sws 0 fast bilinear bA -sws 1 bilinear b -sws 2 bicubic high sharpness r low sharpness b -sws 3 experimental ???? -sws 4 nearest neighbour AM -sws 5 area ba -sws 6 luma bicubic / chroma bilinear r -sws 7 gauss low sharpness B high sharpness AM -sws 8 sinc R -sws 9 lanczos long filter R short filter b -sws 10 bicubic spline r Notes: area upscale is identical to bilinear