LTX-2 Joint Refresh Latent (Disk)

This is the disk-fed twin of IAMCCS_LTX2_JointRefreshLatent. Same job - re-anchor a latent's tail to a fresh reference image so the next segment keeps the subject consistent - except instead of taking the start frames as an IMAGE input, it reads them from a directory of frame files. If your long video pipeline is already writing per-segment frames to disk to keep RAM sane, this is the version you want: no need to round-trip a whole start-image batch through memory just to inject a few frames of it.

Everything else is shared with the in-memory version, by design. The mode enum (tail_then_source_refresh default, tail_only, source_refresh_after_tail), the overlap/strength dials, the tail_preprocess quality pass - identical semantics, and it's the same code path underneath, just swapping the IMAGE input for a directory.

How it works

The only real input swap is start_dir (default iamccs_extension_disk/start): a directory of sequential frame files the pack already writes for its low-RAM flows. The node loads the tail frames from there, VAE-encodes them, and injects them into the latent tail at tail_strength (default 0.9), then re-encodes refresh_image and splices it in just past the protected overlap at source_refresh_strength (default 0.25).

Both injections use the same noise-mask trick as the parent node: mask = 1.0 - strength, so strong injection = hard lock, weak = the model is allowed to vary. overlap_frames (default 9) is in pixel frames and converts to latent frames via the VAE's temporal downscale factor. tail_preprocess with its crf (default 28) gives the tail a light re-encode before it goes in, which helps it blend with the fresh reference instead of clashing.

Inputs and outputs

• start_dir - where the start/tail frames live on disk.
• refresh_image, vae, latent - as in the in-memory version.
• mode, overlap_frames, tail_strength, source_refresh_strength, tail_preprocess, tail_preprocess_crf.

Outputs: latent (refreshed) and report.

Install

ComfyUI Manager → "IAMCCS", or:

cd ComfyUI/custom_nodes
git clone https://github.com/IAMCCS/IAMCCS-nodes.git

Restart. No extra dependencies; it just needs the directory convention your pipeline already uses.

Gotchas

Path discipline is the whole failure mode here. iamccs_extension_disk/start is relative to ComfyUI's working directory, so if the frames land elsewhere - or the node runs before whatever writes that directory - you get empty or stale tail injection and the refresh silently under-delivers. The report string names the injection stages; when the tail stage says zero frames, check the path first. Otherwise, same advice as the parent: keep source_refresh_strength low (0.25 default is a good start) or you'll trade identity drift for frozen motion.