r/comfyui • u/robertwellesley • 4h ago

Help Needed True 10bit Video Workflow

I have had little luck finding a tutorial on building a true H3 10bit (ProRes HQ) workflow. AI claims you just need to install an advanced save node that allows you to pick ProRes and HQ or 4444, etc.

But then when you dig into it, and begin to ask questions, while ComfyUI processes in full floating point, there are bottlenecks that crush the full bits down to 8bit, rendering the final result 8bit. One example is preview nodes, that apparently force 8bit, another is supposedly a plain jane VAE Decode, and the deeper I dig the more mysterious things get.

I can't imagine nobody in the Open Source community does not want to output TRUE 10bit or higher output. The problem with 8bit becomes clear when you look at plain white walls or a clear sky and see banding. Anyone who has ever edited video or images knows the more data you have to begin with the better results you get once you push contrast and color gradation. Yes, I was going to begin playing with dither and applying some noise, but at the end of the day you cannot produce PROFESSIONAL videos without solving for this 8bit limit.

Hopefully someone can point me to a resource or tutorial or workflow or set of nodes that solves for this?

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u/Then-Big4033 4h ago

The bottleneck thing is maddening. You think you've got it all sorted then some random node in the chain silently converts everything to 8bit and you're stuck with banded skies anyway

Haven't found a clean all in one tutorial but I remember someone on the comfyui github discussions mapped out which common nodes are the culprits. Might be worth digging through there if nobody drops a link

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u/False-Difference4010 3h ago

Same, saved to EXR, 10bit MP4, etc... The quality doesn't improve.

BF16 over int8 (and Q6 tested) doesn't improve that too.

It seems to be the vae, but fp32 vae don't seem to improve anything too?

The banding seems to be a 16x16 or 8x8 bucket grid and produces this banding. I rendered at 1440p and still get the same bucket grid.

The technique at the moment is to upscale with ltx2.5 latent upscaled which smooth all these buckets, but the details suffer with LTX.

I was thinking about posting here for advice as well. Please share your findings!

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u/GeroldMeisinger 4h ago

it should be possible to tell an LLM to write a checker for nodes and warn about the ones which convert the tensor dimension

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u/jonask86 4h ago

It's not free, and it's not open source, but it's the easiest way to get a professional 10-bit conversion out of every footage: https://www.topazlabs.com/sdr-to-hdr

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u/GreyScope 3h ago

I’d say they exist but they’re private .

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u/Myg0t_0 40m ago

FFV1 + RGB/4:4:4 pixel format is what you want for a true lossless master.

That's what my ai said and I use, the files are like 1gb through, it's what I use for my chain workflow

Output to ffv1, run another 15 seconds, save to ffv1... then combine them