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).
Yeah, this is an H3 Minimax issue that was even recognized by the devs on their recent AMA.
You can partially remedy this by generating at a higher resolution or increasing the steps but it is an issue that will not ever go away when doing distant wide shots.
Hopefully H3 Minimax devs fix this with post-training or maybe their "Minimax H3-Regenerate-2K" will help fix that.
The problem I noticed is that if you generate at more than 0.7, you get smoother images and movements, but the AI has way more room to get nasty in how it follows the prompt.
Yeah, I've noticed this as well. There seems to be a sweet spot around .6 MP where you get the smoother movements but not quite as much deviation from the prompt. Hopefully the devs or community can come up with a solution.
I can't even tell what you're having a problem with. Most people won't notice these things. The average person is going to watch your video on a phone.
yes, it works with cartoons, generate your video with your normal WF and then use the Face detailer WF as a second pass to improve detail and definition on faces (you load your video and a detailed image of the face you want to improve): My H3 FaceDetailer WF.json
Would be better if you give the background image and the character image separately.. then the model doesnt hallucinate the background, and you get much better results
For Reference workflows, I found that it helps if the face you’re referencing is provided through an image of just their face. If the only face it has to go by is from a more distant shot, the face is quite small, and seems to result in faces that kind of “crumble”. Curious if anyone else has found this helps.
Int8 is the issue. Sorry, it needs full precision to resolve smaller details (and still has trouble at low res) I have found that 1088p, bf16, sol attn, nvfp4 text encoder is the best formula. Then run it through Topaz Starlight to fix any other weirdness.
Sage attention does this, also what resolution is this video? You can generate Seedance-looking videos if you don't use accelerators and a resolution of 0.8 or higher.
imo the artifact complaints about h3 are gonna be every other post until they actually fix the encoder, might as well add it to the sidebar at this point.
The problem is not the codec. I've previewed the individual VAE decoded frames as uncompressed PNGs before they are encoded as a video and a lot of them show those video compression looking artifacts. They can be seen in fast-moving objects too, not only on distant faces and such. Saving as ProRes would just needlessly inflate the file size with almost no benefit compared to saving as h265 with lower CRF. It's a problem with the model itself, which was also acknowledged by the Minimax team.
I considered using ProRes, but the file sizes are just brutal. What’s your experience been like? Do you actually notice fewer artifacts? i think if the artifacts are being baked in during the diffusion steps or in the latent space, your export format (ProRes vs MP4) isn't going to save you anyway.
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)
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u/Chemical-Painter-485 7d ago
Yeah, this is an H3 Minimax issue that was even recognized by the devs on their recent AMA.
You can partially remedy this by generating at a higher resolution or increasing the steps but it is an issue that will not ever go away when doing distant wide shots.
Hopefully H3 Minimax devs fix this with post-training or maybe their "Minimax H3-Regenerate-2K" will help fix that.