H3 Ref Batch (RefPicker -> ref slots)

H3 Ref Batch is a glue node with a thankless but necessary job: it takes the output of a reference picker - one IMAGE batch plus a semicolon-joined path string - and reshapes it into what MiniMax H3's reference node actually wants, which is separate ref_image_N inputs and <Picture N> identity bindings in the prompt. Skip it and the references silently don't arrive; use it and the picker's whole workflow starts working.

It exists because the two ends of the pipeline were built for different shapes. A picker (like this pack's JoyEcho-era RefPicker) returns one batch, one frame per picked reference. H3's reference-to-video node wants discrete slots and explicit labels so it knows that picture 3 is the same person as picture 6. This node is the translation layer between those two worlds.

How it works

Feed it the picker's batch and path string and it:

• Splits the batch into individual frames, one per picked reference, up to nine slots.
• Deduplicates the re-entry duplicates the picker schedules for LTX - those are meaningless for ref2va, because H3 binds all references at t=0.
• Derives a character name from each path's parent folder, and builds the <Picture N> is the same person binding lines for every character, deduping variant folders (rae_night and rae-wet fold into one person).
• Preprends those binding lines to your prompt and emits them as prompt_out, so the model sees the identities before the prose.

The inputs are prompt, reference_image (the batch), and picked_path (the string). Outputs are nine ref_N slots, prompt_out, and a report string that tells you what actually got attached - the console logs the same line, so a mismatch is visible rather than silent.

Installing it

Part of the ComfyUI-H3-Multishot pack:

cd ComfyUI/custom_nodes
git clone https://github.com/jlucasmcrell/ComfyUI-H3-Multishot

Or search H3 Multishot in ComfyUI Manager. Requires ComfyUI v0.30.0+. Reference images require the ref2va checkpoint variant; on fl2va there are no reference rows and this whole lane is inert.

Gotchas

The trap this node exists to fix, and the one you'll still hit: if picked_path starts with ( - the picker's "no references picked" marker - the node passes your prompt through unchanged and emits nothing, with a report saying (no references). That's correct behavior, but it's easy to read as "the node is broken" when it's really "the picker found nothing to pick." Check the report string before chasing the wiring. And when you're wiring character references in, remember the rule from the pack's prompting docs: group photos by person (reference_subjects: 3,3) or H3 averages them into one face.