LTX Director Motion Brush V2 Crop Guides

Some LTX Director workflows crop frames off the end of the timeline - you shorten a segment, trim the tail, tighten a transition - and the latent the guide node built still holds the old, longer frame count. Mismatch that and you get a video that runs long, or keyframes that land on the wrong frames. LTXDirectorMotionBrushV2CropGuides is the small helper that prevents that drift: it reads how many frames the conditioning says should be cropped, trims that many off the end of the latent, and clears the now-stale keyframe metadata so nothing downstream points at frames that no longer exist.

It's a quiet consistency node, one of those "Motion Brush-safe" helpers the pack re-exported from upstream Director so its workflows load without requiring the original LTX Director package installed. Like its sibling DirectorGuide, it exists under the LTXDirectorMotionBrushV2* name to coexist with any upstream install.

The inputs and outputs

Honestly, there's nothing to configure:

• positive and negative (CONDITIONING) - passed through, and their keyframe metadata gets cleaned.
• latent (LATENT) - the video latent to trim.

Outputs are the same three, trimmed and consistent: positive, negative, latent. Wire it in the path between the guide insertion node and the sampler, exactly where the workflow puts it, and you're done. It decides the crop count itself by inspecting the positive conditioning - you don't tell it how many frames to cut.

Why it's in the workflow at all

If you're building your own LTX Director-style graph from scratch, you might skip this node and never notice the difference - the latent simply carries a few extra frames and the video comes out slightly long. But once you start using retakes and per-image segment lengths, frame accounting stops being forgiving. LTX 2.3 is strict about its frame math (frame count divisible by 8 plus 1, width/height by 32), so a latent that disagrees with the conditioning tends to fail loudly rather than gracefully. This node exists to make the disagreement impossible.

Install

It ships in the pack:

comfy node install ltx-director-motion-brush
# or clone into ComfyUI/custom_nodes, then restart ComfyUI

Same sibling requirements as the rest of the pack (ComfyUI-LTXVideo, comfyui-kjnodes, ComfyUI-Impact-Pack) plus the LTX 2.3 stack and Lightricks IC-LoRA models for the full workflow.

The honest take

This is the least glamorous node in the pack, and it's not one you'll ever tune. Its value is purely negative - it prevents a class of "why is my video 12 frames too long / why are my keyframes late" headaches that are miserable to debug because they only appear intermittently. Leave it wired where the workflow has it, don't touch it, and spend your energy on the motion tracks. That's exactly what it's for.