UV Save Master

If your render is heading into Premiere, Resolve, or After Effects, a h.264 mp4 is the wrong tool. Editors want intermediate codecs - ProRes, DNxHR - big, fast-to-decode, edit-native files that don't fall apart under a second generation of compression. UV_SaveMaster is the pack's answer to that: one node that exports your frame batch as a proper mastering file, or as a PNG sequence for the compositing crowd.

It's a terminal output node with a short list of presets, and the names tell the whole story:

• Editorial Master - ProRes 422 HQ - the default editorial workhorse
• Alpha Master - ProRes 4444 - for sources with transparency
• Post Master - DNxHR HQ and DNxHR HQX - Avid-friendly, 8-bit and 10-bit
• Archive Frames - PNG Sequence - hands off to UV_SaveSequence under the hood
• YouTube MP4 - the one "delivery" escape hatch

Under the hood it's not a third encoder at all - it delegates to UV_SaveVideo (or UV_SaveSequence for the PNG option), so you get the same ffmpeg command builder, the same profile tables, and the same behavior as if you'd wired those nodes yourself. The input fields confirm it: images, output_path (default master.mov), preset, fps (default 24), overwrite. That's it - this node exists to hide the codec plumbing behind a dropdown, and it does that well.

The one thing to internalize before you click run: intermediate files are enormous, and that's correct. ProRes 422 HQ of a 24fps clip is going to be orders of magnitude bigger than the same render as h264. That's the price of an edit-friendly format, and if you're surprised by it, this node isn't for you - the pack's UV_SaveVideo with the youtube_h264 profile is what you actually want. Masters are for the pipeline, delivery files are for the internet.

Where people get burned:

• The alpha trap. Pick "Alpha Master - ProRes 4444" on a source with no alpha and you've just tripled your disk usage for zero benefit. UV_MetadataProbe's alpha_likely_present output exists precisely to check this before you export.
• Codec availability. ProRes (prores_ks) and DNxHR (dnxhd) encoders aren't in every ffmpeg build - some Windows static builds skip them. The pack probes your ffmpeg at import and the export will fail with a clear ffmpeg error if the encoder is missing; grab a fuller ffmpeg build.
• The extension has to match. Default output is .mov, which is right for ProRes and DNxHR. Renaming to .mp4 won't work for these codecs - ffmpeg will refuse. Match the container to the codec.

Install

Same as the whole pack:

cd ComfyUI/custom_nodes
git clone https://github.com/GeekatplayStudio/ComfyUI-UniversalVideoIO
cd ComfyUI-UniversalVideoIO
pip install -r requirements.txt

Restart ComfyUI. No model downloads - the only real dependency is a ffmpeg build that actually includes the encoder your preset needs, which is worth verifying before a long master export. And remember that relative output paths resolve against ComfyUI's working directory (usually its install root), so master.mov lands there, not in output/. Absolute paths or a masters/ prefix keep things tidy.