Wan VACE Prep

This is a small collection of ComfyUI nodes designed to help make common Wan VACE tasks less complicated.

Quick Start

Install via ComfyUI Manager: Search for "Wan VACE Prep"

Or clone this repository:

cd /path/to/comfyui/custom_nodes
git clone https://github.com/stuttlepress/ComfyUI-Wan-VACE-Prep

Nodes

• VACE Outpaint
• VACE Join
• VACE Join (Batch)
• VACE Batch Context
• VACE Extend
• Load Videos From Folder (Simple)

VACE Outpaint

Prepares a video for outpainting using an interactive canvas widget. Position and size an output window over your source frames — regions outside the source become the outpaint area. Builds a VACE control video and mask ready for generation.

Nodes 2.0 incompatibility: This node is known to malfunction under ComfyUI's Nodes 2.0 renderer. No fix is planned until ComfyUI publishes node development documentation.

Parameters:

Parameter	Default	Description
images		Source video frames

Outputs:

Output	Description
control_video	VACE control video input. Source content placed within the output window; overhanging regions filled with gray (0.5).
control_mask	VACE control mask input. White (1) where outpainting should occur, black (0) over source content.
width, height	Output video dimensions
length	Frame count

https://github.com/user-attachments/assets/999b4019-788b-4d6a-8d73-dd3f402176d2

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VACE Join

For smoothly joining two video clips together. Builds VACE controls for the transition using context frames from each clip to guide frame generation.

Parameters:

Parameter	Default	Description
context_frames	8	Reference frames from each video edge that VACE uses for interpolation. These frames guide the model and are preserved in the output. Must be a multiple of 4.
replace_frames	8	Number of frames at each transition edge to discard and regenerate. These create the actual transition blend zone. Must be a multiple of 4.
new_frames	0	Number of completely new frames to generate between the two clips, extending the transition duration. Must be 0 or a multiple of 4.

Outputs:

Output	Description
control_video	VACE control video input
control_mask	VACE control mask input
width, height, length	Control video dimensions
start_images	Video 1 segment that precedes context frames and the transition
end_images	Video 2 segment that comes after the transition and context frames
context_frames, replace_frames, new_frames	Parameter passthrough for optional downstream wiring

https://github.com/user-attachments/assets/5b70b5af-8d88-4c0f-a5a7-cdbe0657ce8c

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VACE Join (Batch)

Batch-aware version of VACE Join for processing multiple video pairs. Handles first/last iteration edge cases.

Parameters:

Parameter	Default	Description
video_1		First video in the pair (IMAGE type)
video_2		Second video in the pair (IMAGE type)
is_first	false	Set true for first iteration (index=0) — includes full beginning of video_1 in start_images
is_last	false	Set true for last iteration — includes full ending of video_2 in end_images
context_frames	8	Reference frames from each video edge for VACE interpolation. Must be a multiple of 4.
replace_frames	8	Frames at each transition edge to discard and regenerate. Must be a multiple of 4.
new_frames	0	New frames to generate between clips. Must be 0 or a multiple of 4.
debug	false	Log diagnostic information to the console

Outputs:

Output	Description
control_video	VACE control video input (context frames + placeholder for generation)
control_mask	VACE control mask input (masks generation region)
width, height, length	Control video dimensions
start_images	Video segment from video_1 to preserve (excludes transition region)
end_images	Video segment from video_2 to preserve (only populated on last iteration)
context_frames, replace_frames, new_frames	Parameter passthrough for optional downstream wiring

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VACE Batch Context

This node drives my Wan VACE Video Joiner workflow. It may not be useful outside of that context.
Establishes iteration context for batch video processing workflows. Manages file paths, iteration tracking, and provides first/last flags for proper handling of video sequence boundaries. Supports an optional loop mode that generates a wrap-around transition between the last and first video for seamless looping output.

Parameters:

Parameter	Default	Description
input_list		List of video filenames to process (STRING, force input)
input_dir		Directory containing input videos
project_name	.	Project name — workflow files created under ComfyUI/output/project_name. Use period (.) for no project name.
index	0	Current iteration index (0-based). Valid range: 0 to (number of videos - 2) normally, or 0 to (number of videos - 1) when make_loop=true
debug	false	Log iteration details to the console
make_loop	false	Enable loop mode — adds one extra iteration that pairs the last video with the first, creating a seamless loop. When true, is_first and is_last are always false.

Outputs:

Output	Description
work_dir	Working directory path for intermediate files
workfile_prefix	Filename prefix for this iteration's work files
video_1_filename	Full path to first video in current pair
video_2_filename	Full path to second video in current pair
is_first	True if this is the first iteration (index=0). Always false when make_loop=true.
is_last	True if this is the last iteration. Always false when make_loop=true.
assemble_video	True on the final iteration — used to gate the assembly step. Equivalent to is_last when make_loop=false; fires on the loop-closing iteration when make_loop=true.

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VACE Extend

Extends a video from an arbitrary frame position. Context frames preceding the extension point build a VACE control video for conditioning.

Parameters:

Parameter	Default	Description
extend_from_idx	-1	Frame to extend from (negative counts from end, e.g., -1 = last frame)
context_frames	8	Reference frames preceding extend_from_idx for VACE conditioning. Must be a multiple of 4.
new_frames	25	Number of new frames to generate (must be 4n+1: 1, 5, 9, 13, 17, 21, 25...)

Outputs:

Output	Description
control_video	VACE control video input
control_mask	VACE control mask input
width, height, length	Control video dimensions
start_images	Video segment that precedes the context frames and the extension
context_frames, new_frames	Parameter passthrough for downstream wiring

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Load Videos From Folder (Simple)

Loads all videos from a folder, concatenated into a single image batch.

Optionally connect a VideoHelperSuite Meta Batch Manager node to process large collections in RAM-safe chunks. If you are joining a large number of video files and running out of system memory as they concatenate, this is the solution. From the VHS Meta Batch Manager node documentation:

The Meta Batch Manager allows for extremely long input videos to be processed when all other methods for fitting the content in RAM fail. It does not affect VRAM usage. It must be connected to at least one Input (a Load Video or Load Images) AND at least one Video Combine.

See the VHS Meta Batch Manager node documentation for more information.

Meta Batch Manager rule of thumb: set frames_per_batch to roughly 10× your available RAM (not VRAM) in GB — so 32 GB → 320 frames, 64 GB → 640 frames, 128 GB → 1280 frames.

• Formats: webm, mp4, mkv, gif, mov
• All videos must have identical resolution
• No external dependencies

Parameters:

Parameter	Default	Description
folder_path		Full pathname of the directory holding input videos
debug	false	Log video details and progress to the console
meta_batch	(optional)	Connect to VideoHelperSuite Meta Batch Manager to load videos in batches

Outputs:

Output	Description
images	Concatenated image batch ready for video creation

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Technical Notes

4n+1 frame rule. The Wan model generates 4n+1 frames at a time. If you request a different count, it silently rounds down to the nearest 4n+1. For this reason, parameters are restricted to multiples of 4 or 4n+1, and when necessary the nodes add +1 to the generated frame count.

Class names vs. display names. Some internal class names (e.g., WanVACEPrep) don't match the current display names (e.g., "VACE Join"). This is intentional — renaming classes would break existing workflows that reference them. Once ComfyUI's node renaming API is stable, a refactoring pass will align them.

Nodes 2.0 renderer. These nodes have not been tested under ComfyUI's Nodes 2.0 renderer and may or may not work correctly with it. Testing and support will be added sometime after ComfyUI publishes documentation for node developers to work from.

License

MIT License — feel free to use, modify, and distribute.