| --- |
| license: apache-2.0 |
| base_model: |
| - Wan-AI/Wan2.1-T2V-14B |
| --- |
| |
| # VAE Reconstruction & Color Expansion Evaluation |
| ### Wan2.1 Base VAE vs HDR VAE |
|
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|
|
| ## 📊 At-a-Glance Summary |
|
|
| **Color expansion (HDR VAE vs GT):** |
| - LAB volume: **~+50%** |
| - Saturation: **~+27%** |
| - Unique colors: **~+30%** |
| - Gradient strength: **~+7%** |
|
|
| **Structural cost:** |
| - SSIM: **~-2%** |
| - MSE: **~+50%** |
|
|
| ### Key takeaway |
| HDR VAE significantly increases chromatic richness and color diversity, |
| but reduces structural fidelity and increases reconstruction error relative to Wan2.1 Base VAE. |
|
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| --- |
|
|
| ## 🧪 Evaluation Setup |
|
|
| - Task: Image reconstruction (VAE decoding comparison) |
| - Models: |
| - Wan2.1 Base VAE |
| - HDR VAE |
| - Ground Truth (GT) |
| - Mode: Deterministic image-to-image reconstruction |
| - Metrics: |
| - Color statistics (HSV / LAB / RGB) |
| - Structural metrics (SSIM, MSE, PSNR) |
| - Frequency features (edges, gradients) |
| - Entropy + color diversity |
|
|
| --- |
|
|
| ## 📈 Key Findings |
|
|
| ### 🎨 Color behavior |
| - **Wan2.1 Base VAE:** slight compression of GT color space |
| - **HDR VAE:** strong expansion of color space (+30% to +50%) |
|
|
| ### 🧱 Structure |
| - **Wan2.1 Base VAE:** closer to GT, smoother output |
| - **HDR VAE:** sharper, more high-frequency artifacts |
|
|
| ### 👁️ Perceptual behavior |
| - **Wan2.1 Base VAE:** higher fidelity, lower distortion |
| - **HDR VAE:** more vivid but less faithful reconstruction |
|
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| --- |
|
|
| ## 📊 Quantitative Results vs GT |
|
|
| ### Wan2.1 Base VAE |
| - Brightness: -0.71% |
| - Contrast: -0.23% |
| - Saturation: -0.11% |
| - Entropy: -0.08% |
| - Dynamic range: -0.46% |
| - Edge density: -15.35% |
| - Gradient strength: -5.90% |
| - LAB color volume: -5.00% |
| - Quantized colors: -6.60% |
| - Unique colors: +7.90% |
| - Sharpness: -45.65% |
|
|
| --- |
|
|
| ### HDR VAE |
| - Brightness: +0.90% |
| - Contrast: +0.93% |
| - Saturation: +26.90% |
| - Entropy: +0.17% |
| - Dynamic range: -0.07% |
| - Edge density: +14.98% |
| - Gradient strength: +7.10% |
| - LAB color volume: +48.60% |
| - Quantized colors: +45.60% |
| - Unique colors: +29.50% |
| - Sharpness: +32.15% |
|
|
| --- |
|
|
| ## 🧮 Reconstruction Quality |
|
|
| ### Wan2.1 Base VAE |
| - SSIM: **0.822** |
| - PSNR: **25.86** |
| - MSE: **180.88** |
|
|
| ➡️ Best structural fidelity and lowest reconstruction error |
|
|
| --- |
|
|
| ### HDR VAE |
| - SSIM: **0.806** |
| - PSNR: **24.06** |
| - MSE: **278.08** |
|
|
| ➡️ Higher distortion but stronger chromatic expansion |
|
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| --- |
|
|
| ## 🧠 Interpretation |
|
|
| **Color axis → Winner: HDR VAE** |
| - Largest increase in LAB volume, saturation, and color diversity |
|
|
| **Structure axis → Winner: Wan2.1 Base VAE** |
| - Closer SSIM and lower MSE |
|
|
| **Fidelity axis → Winner: Wan2.1 Base VAE** |
| - More faithful reconstruction of GT distribution |
|
|
| --- |
|
|
| ## 🏁 Final Conclusion |
|
|
| HDR VAE acts as a **chromatic expansion decoder**, increasing color space occupancy and high-frequency detail. |
|
|
| Wan2.1 Base VAE remains closer to the **ground-truth manifold**, prioritizing structural and perceptual fidelity over color amplification. |
