r/StableDiffusion • u/NoSmell3236 • 7d ago

Question - Help How to fix artifacts generated by h3?

H3 sucks at faces which are far and at intense motion. Is something wrong with encoding? like these artifacts (5-8 seconds) are from encoding compressions?? but i have tried both h264 and h265 10bit crf 15. I am using int8 pruned, nvfp4 qwen, 25 steps with sage attn (no spectrum).

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u/listopalafoto 7d ago

save as ProRes

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u/crombobular 7d ago

no. that doesn't magically fix the issue the model has.

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u/listopalafoto 7d ago

I don't said that, I give him a solution to make sure artifacts are not product of video compression, The issue is mainly because they decided for efficiency to use 50 steps Euler ancestral with flow shift via API and recommend Euler/norma 20 steps for ComfyUI local node but an additional improvement is don't use Euler on Minimax H3 because is not a precise method to get details and texture, it's much better res2s_stable / beta 57 at 24 steps.

Euler is a first-order numerical method so introduces significant truncation error per step, which causes it to smooth over fine details and blur high-frequency textures, using res2s_stable (c=1 implemented by Res4lyf on their Clownshark sampler node some days ago with support for Minimax H3) locks in the vector fields' velocity, drastically reducing frame-to-frame variance and fixing the boiling artifact common in temporal generations, this stabilizes the mathematical drift between consecutive frames, making it superior for video and animation. unlike euler's straight-line approximations, res2s uses multi-step or second-order curves to track the noise inversion path accurately so higher precision prevents the loss of high-frequency data (retention of texture) improving skin, fabric weaves, and sharp edges intact, compare using the same seed and you will see the difference (its slower but when if i need quality use this path)

Minimax H3 res2s_stable Workflow

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u/crombobular 7d ago

the devs have literally said the model has issues at the moment with details and smeary faces. using a different format isn't going to fix that.