Wan Ratio & FPS

Every Wan workflow has that moment where you type 1280x720, hit run, and get "resolution not compatible" (or a video that decodes two frames short). Wan's VAE wants dimensions divisible by 16, and 1080p isn't actually 1920x1080 - it's 1920x1088. The Wan Ratio & FPS node is a tiny calculator that spits out the correct, Mod-16-compliant width and height plus an FPS value, so you stop hand-computing resolutions.

It's the utility node in Magos Digital Studio's ComfyUI-Magos-Nodes pack. The pack's headline is the DWPose editor/retargeter chain, but this little node is genuinely useful standalone - it's a resolution dashboard for WanAnimate and anything else that wants clean dimensions.

How it works

Pick an aspect ratio (16:9, 9:16, 1:1, 4:3, 3:4, 21:9, or Custom), pick a quality tier (480p / 720p / 1080p), and it looks up a hard-coded table of Mod-16-safe resolutions. 16:9 at "720p" gives 1280x720; at "1080p" it gives 1920x1088 (that extra 8 is the Mod-16 rounding, and it's correct - Wan wants it). If you pick Custom, your custom_width/custom_height get auto-rounded down to the nearest multiple of 16, so even a sloppy value like 1337 lands on something the model accepts.

The FPS side is a separate dropdown (fps_preset: 12, 15, 23.976, 24, 25, 30, 48, 50, 60, or Custom) with a custom_fps override. Outputs are dead simple: width (INT), height (INT), fps (FLOAT).

Why you'd bother

The whole thing saves you two minutes of arithmetic, which sounds trivial until you've been burned by a 21:9 ratio at 1080p and can't remember what the mod-16 version is. It also keeps your graph readable - one node with clear widgets instead of a pile of int constants scattered through the workflow.

A couple of honest caveats:

• The values are presets, not auto-detected. If your target model needs a specific resolution (some Wan workflows use 832x480 or other oddballs), use Custom or just compute it yourself.
• It's built around WanAnimate's Mod-16 requirement, but the outputs are plain INT/INT/FLOAT, so they wire into anything that accepts those - a VHS resize node, a latent size node, an LTX or Hunyuan Video workflow. Nothing Wan-specific about the output types.

Install

It's part of the pack, so install once, use all six nodes:

cd ComfyUI/custom_nodes
git clone https://github.com/MagosDigitalStudio/ComfyUI-Magos-Nodes

Restart ComfyUI. It lives under MAGOS Nodes → Utils. Unlike the pose nodes in this pack, this one needs nothing special - no Kijai dependency required, no model downloads.

Common issues

Not much to trip on, honestly. The one thing that catches people: if ratio is set to something other than Custom, your custom_width/custom_height are ignored, so don't edit those and wonder why nothing changed. And remember 1080p isn't 1080 - if you were hard-coding 1920x1080 before, the "1088" output is the node doing its job, not a bug.