os.path.splitext

The most common path operation in any ComfyUI workflow is also the one people reinvent by hand the most: "take frame_0072.png, give me the frame_0072 so I can build frame_0072_upscaled.png." os.path.splitext is that operation. It splits a path into (root, ext) - the name and its extension - so you can modify one without mangling the other.

It's from the ovum/path/os.path family in comfy-ovum, a faithful wrapper over Python's os.path.splitext().

How it works

Returns two STRING outputs:

• root: everything up to (but not including) the final extension. C:\renders\frame_0072.png → C:\renders\frame_0072
• ext: the extension, dot included. .png

Path from:

• path (STRING, required): the widget.
• path_in (PATHLIKE,STRING, optional): link-only; overrides the widget when connected.

The split is on the last dot in the final path component, so archive.v2.png → root archive.v2, ext .png. Files with no extension return an empty ext and the whole name as root. Pure string work - no disk access, safe on anything.

The workflow it enables

This is the foundation of dynamic output naming:

1. Take a loader's file path, split off the ext.
2. Run the root through a format/concat node to append a suffix - Python String Format from the same pack is perfect: {arg0}_hires.
3. Re-add an extension (maybe a different one - .png → .jpg).
4. Feed the result to your saver.

Now the output name is derived from the input name instead of hardcoded, which means a batch graph renames correctly for every file it touches. It also earns its keep for filtering: checking ext == '.mp4' vs .png to route files to the right branch, or detecting whether a filename already has an extension before you go appending one.

Installing it

Pack-wide, once:

cd ComfyUI/custom_nodes
git clone https://github.com/sfinktah/comfy-ovum

Or ComfyUI Manager → "comfy-ovum" → Install → restart. No models, no extra deps.

Gotchas

• It's splitext, not split. The plain os.path.split node separates folder from filename; this one separates extension from name. They're easy to confuse in a search box, and the results are not interchangeable.
• Last-dot rule. my.file.name → root my.file, ext .name. That matches Python and is usually what you want, but if a file genuinely has dots in its name, splitext won't strip "all extensions."
• The dot stays with the extension. If you build output names, remember ext already includes the leading dot - {root}_hires{ext} gives frame_0072_hires.png, while {root}_hires.{ext} would give you a double dot.

If you wire a saver's path into splitext once, rename logic, extension checks, and output-name construction all fall out of it. It's the highest-value-per-input node in the whole path family.