WebP Crop Impact Study
Study how cropping (reducing the image area while keeping the analysis fragment at full resolution) affects WebP compression quality. Unlike the resolution-impact study which downscales the entire image, this study crops the image to different sizes around a fixed 200×200 analysis fragment, eliminating the confounding effect of reduced resolution on quality metrics. Quality metrics are measured only on the analysis fragment, ensuring consistent comparison across crop levels.
Contents
- SSIMULACRA2 vs BPP
- BUTTERAUGLI vs BPP
- PSNR vs BPP
- SSIM vs BPP
- SSIMULACRA2 vs Crop
- BUTTERAUGLI vs Crop
- PSNR vs Crop
- SSIM vs Crop
- BITS PER SSIMULACRA2 PER PIXEL vs Crop
- BITS PER BUTTERAUGLI PER PIXEL vs Crop
- BITS PER PSNR PER PIXEL vs Crop
- BITS PER SSIM PER PIXEL vs Crop
- BPP vs Crop
- ENCODING TIME PER PIXEL vs Crop
- Visual Comparison
Data Downloads
Visual Comparison
Side-by-side comparison of encoding artifacts on the most representative image fragments, selected automatically from the dataset using Butteraugli spatial distortion analysis. Identifies the image and fragment where the choice of encoding parameters has the greatest anisotropic impact on quality. One fragment is selected per target metric group and shared across all target values within that group for direct comparability. The dashed rectangle marks the fragment used for the comparisons below. Per-pixel anisotropic variance of Butteraugli distortion — bright regions show where quality varies most across tile-parameter values. The variance maps for each target value are averaged to select one fragment for the entire group. Nearest-neighbour 3× zoom of the selected fragment, comparing original against each encoding variant. Images are served losslessly to preserve pixel fidelity. Click any image to open it in the lightbox viewer. Per-variant Butteraugli distortion maps shown as viridis heatmaps at uniform scale (darker = higher distortion). Reveals where each encoder concentrates its errors. The dashed rectangle marks the fragment used for the comparisons below. Per-pixel anisotropic variance of Butteraugli distortion — bright regions show where quality varies most across tile-parameter values. The variance maps for each target value are averaged to select one fragment for the entire group. Nearest-neighbour 3× zoom of the selected fragment, comparing original against each encoding variant. Images are served losslessly to preserve pixel fidelity. Click any image to open it in the lightbox viewer. Per-variant Butteraugli distortion maps shown as viridis heatmaps at uniform scale (darker = higher distortion). Reveals where each encoder concentrates its errors. The dashed rectangle marks the fragment used for the comparisons below. Per-pixel anisotropic variance of Butteraugli distortion — bright regions show where quality varies most across tile-parameter values. The variance maps for each target value are averaged to select one fragment for the entire group. Nearest-neighbour 3× zoom of the selected fragment, comparing original against each encoding variant. Images are served losslessly to preserve pixel fidelity. Click any image to open it in the lightbox viewer. Per-variant Butteraugli distortion maps shown as viridis heatmaps at uniform scale (darker = higher distortion). Reveals where each encoder concentrates its errors.Anisotropic Variance Analysis
Matched Bits Per Pixel
Selected Image & Fragment Location
Anisotropic Distortion Map
Fragment Comparison
Distortion Map Comparison
Matched Butteraugli
Selected Image & Fragment Location
Anisotropic Distortion Map
Fragment Comparison
Distortion Map Comparison
Matched Ssimulacra2
Selected Image & Fragment Location
Anisotropic Distortion Map
Fragment Comparison
Distortion Map Comparison
Static SVG Figures
Downloadable vector graphics for use in papers, presentations, or offline analysis.
- webp-crop-impact_butteraugli_vs_crop.svg
- webp-crop-impact_ssim_vs_crop.svg
- webp-crop-impact_psnr_vs_crop.svg
- webp-crop-impact_ssimulacra2_vs_bits_per_pixel.svg
- webp-crop-impact_bits_per_pixel_vs_crop.svg
- webp-crop-impact_encoding_time_per_pixel_vs_crop.svg
- webp-crop-impact_bits_per_butteraugli_per_pixel_vs_crop.svg
- webp-crop-impact_ssim_vs_bits_per_pixel.svg
- webp-crop-impact_ssimulacra2_vs_crop.svg
- webp-crop-impact_bits_per_psnr_per_pixel_vs_crop.svg
- webp-crop-impact_psnr_vs_bits_per_pixel.svg
- webp-crop-impact_bits_per_ssimulacra2_per_pixel_vs_crop.svg
- webp-crop-impact_butteraugli_vs_bits_per_pixel.svg
- webp-crop-impact_bits_per_ssim_per_pixel_vs_crop.svg
