VP9 Codec

VP9 Codec is the other half of the codec-factory pair in ComfyUI Core Video Nodes (Immac/ComfyUI-CoreVideoMocks), and if you've read the AV1 Codec node, you've basically read this one too. Same shape, different codec: one input, crf, an INT with default 30 (range 0–63, tooltip "Constant Rate Factor (CRF) for VP9 encoding. Lower values mean better quality"), and one output, codec, a DICT holding {"codec": "VP9", "crf": crf}.

VP9 is Google's royalty-free codec, the direct ancestor of AV1 and for years the web's default - it's what made 4K YouTube watchable without H.264's licensing headache. Compared to AV1 it's the pragmatic choice: easier to find encode hardware for, dramatically faster to encode, still leagues better than H.264 at the same bitrate. The trade is compression efficiency - AV1 beats it by roughly 30% at equal quality. For a webm output, VP9 is still the boring, reliable option.

What's actually interesting about it

The interesting bit isn't the node - it's what the two codec nodes say about the pack's design. Instead of one big "choose your codec" dropdown buried in the encoder, the author split codec selection into its own node that emits a structured object. It's clean, it composes, and it's a reasonable guess at what a core ComfyUI video API might look like. That's the value here, because the pack is otherwise what GitHub calls it: "A set of mock nodes for RFC purposes." Two stars, no community footprint, untouched since March 2025.

Install

cd ComfyUI/custom_nodes
git clone https://github.com/Immac/ComfyUI-CoreVideoMocks

Restart ComfyUI. No pip dependencies, no model files, no ffmpeg - the pack is pure Python on ComfyUI's own folder_paths. ComfyUI Manager also has it under "ComfyUI Core Video Nodes."

The honest verdict

As a mock, it does its job: you understand CRF, you understand what a codec object is, and you understand why the encoder wants one. As a tool, it encodes nothing. Wire the codec dict into the pack's Encode Video Stream node and you'll hit the bug waiting there (see that node's article). Want real VP9 or AV1 encoding? ffmpeg. Want to learn the API shape the ComfyUI core video nodes might one day take? This node is a fine little study aid.