BlehEnsurePreviewer

A lot of people install ComfyUI-bleh specifically for its previewer - better TAESD-based previews than ComfyUI's stock system, with a higher max size than the hardcoded 512px cap, batch previews, throttling so you're not decoding a preview three times a second, and video-model preview support for things like Wan and Hunyuan. All of that is real and useful. The catch is that ComfyUI only has one active previewer at a time, and other custom node packs sometimes register their own and quietly take it over. This node is the fix when that happens.

It's a pure bridge node: it takes any_input, passes it straight through unchanged, and its only real effect is a side effect - when it executes, it re-asserts that bleh's previewer is the one actually hooked up. The README names a specific, known conflict: ComfyUI-VideoHelperSuite will overwrite bleh's previewer if its own animated-preview option is enabled, and depending on which pack happens to load second, the outcome can go either way. This isn't a bleh bug so much as an unavoidable consequence of there being exactly one previewer slot and no coordination protocol between packs that want it.

Practically, you drop this node somewhere in your graph - since it accepts and returns anything, it doesn't care what's flowing through it - after you notice previews have reverted to ComfyUI's plain, low-res default instead of bleh's higher-quality output. Running it for that generation re-establishes bleh as the active previewer.

Inputs: any_input (wildcard). Output: * (wildcard, identical to what came in). This node doesn't configure preview quality itself - that's a separate concern, governed by an optional blehconfig.yaml file (copied from the blehconfig.yaml.example shipped in the repo, then edited, with a ComfyUI restart required to apply changes). What this node controls is purely which previewer is active, not how it behaves once it is.

Worth knowing what you're actually protecting when you use this node: bleh's previewer settings cover things like max_size (bumping past ComfyUI's hardcoded 512px preview cap), max_batch/max_batch_cols for previewing more than one image in a batch at a time, throttle_secs for not re-decoding a preview on every single step, and preview_device/preview_dtype if you want previews running somewhere other than your main GPU. None of that matters if a different pack has quietly taken the previewer slot back - which is the whole reason this node exists as a standalone fix rather than something you'd expect to need at all.

Install is the standard route: ComfyUI Manager search for "ComfyUI-bleh," or a manual git clone https://github.com/blepping/ComfyUI-bleh into custom_nodes followed by a restart. No extra dependencies for this node specifically, though the previewer feature it protects does pull in TAE model weights behind the scenes for the quality upgrade.

If your previews look like ComfyUI's plain default rather than bleh's nicer output and this node doesn't seem to fix it, check your custom node load order for something else patching the previewer - VideoHelperSuite is the one the README names outright, but it's not necessarily the only pack capable of doing it. Worth ruling that out before assuming your blehconfig.yaml settings are wrong.