LTX Director Motion Brush V2 Retake Source Preview

Retake Mode is one of the best features of the Motion Brush workflow: you select a section of an existing video, re-generate just that range, and the model keeps everything around it intact. The problem is that you're working blind - the generated video comes out, but there's no easy way to see it next to the original range you asked it to redo. This node fixes exactly that. It reads the Retake Mode source video straight out of the main node's guide_data, decodes the same frame range the retake covers, and hands it to you as both an image batch and a video for comparison.

The included workflow makes this clever: it feeds this node's output and the generated video into an ImpactSwitch, so you can flip back and forth between source and retake with one click. That's the whole point - before/after, without hunting through your input folder.

The inputs that matter

• guide_data - connect this from LTXDirectorMotionBrushV2. This is where the source video path and the retake's start frame live.
• width / height / duration_frames - leave at 0 and they're inferred from the guide data or the optional latent. Set them only if you want a specific comparison resolution.
• resize_method (default "match director guide") - mirrors how the Director retake guide path resizes the source, so the comparison is apples-to-apples. Other options exist for manual setups.
• resample_mode (default nearest) - how frames are resampled when the source video's FPS doesn't match the Director timeline. linear if you want smoother interpolation.
• on_missing (default blank frame) - what happens when there's no retake source to show. blank frame gives you a black placeholder so the workflow still runs; error throws instead. Pick error during setup if you'd rather be told loudly that the retake video never uploaded.

Outputs

retake_source_images (IMAGE batch), retake_source_video (VIDEO), frame_idx, render_summary (a JSON string with status - handy when you're getting black frames), and retake_source_any, a wildcard copy for * sockets.

Install

It's part of the pack, not a separate install:

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

Needs the usual siblings (ComfyUI-LTXVideo, comfyui-kjnodes, ComfyUI-Impact-Pack - Impact for the switch trick) plus the Lightricks IC-LoRA models if you want the full workflow.

Common gotchas

• Black output. Check render_summary - if it says the retake mode isn't active in guide data or the source is still uploading, that's your answer, not a node bug. Retake Mode also enforces a 6-second minimum selection; short selections won't behave.
• Wrong frame range. The node decodes from the retake's start frame for the same duration - if your comparison looks shifted, it's almost always a timeline/video FPS mismatch, which is exactly what resample_mode exists for.

It's a small node with a narrow job, but it's the difference between "I tweaked the retake and hope it's better" and actually seeing what changed. In a workflow where retakes are your main iteration loop, that's not nothing.