Processing

Processing is everything WanGP does around generation to prepare inputs, control what the model produces, or refine media after it exists.

Use this guide when you are deciding how to prepare a Control Video, build masks, use reference images, extend a video, or apply late postprocessing.

At A Glance

Stage	When It Happens	What It Does
Preprocessing	Before generation	Converts source media into model-ready inputs such as pose, depth, masks, control frames, or cleaned references.
Generation-time processing	During generation	Uses temporal, spatial, mask, reference, and sliding-window controls to decide what the model should change or preserve.
Postprocessing	After generation	Improves or transforms completed images, videos, or audio with upscaling, remuxing, audio tools, or late media processing.

Before Generation: Preprocessing

Preprocessing changes what the model receives as conditioning. It does not produce the final media by itself; it prepares the inputs that guide generation.

Common preprocessing jobs:

• Resize and resample inputs to the model frame rate and output resolution.
• Extract pose, depth, canny, raw-frame, mask, or other control information from a Control Video.
• Prepare Video Masks for masked-area or non-masked-area workflows.
• Prepare reference images before inserting people, objects, landscapes, or exact frames.
• Build injected reference frames for temporal inpainting or spatial outpainting.
• Prepare source media for video continuation or long-video sliding windows.

Control Videos

Control Video processing tells the model what structure, motion, or area to follow.

• Keep Unchanged: use the Control Video as the source structure without extracting a new annotation.
• Transfer Human Motion: extract pose or Open Pose style motion from a source video.
• Depth / Canny / Similar Structure Controls: extract scene structure while letting the prompt change appearance.
• Inpainting: mark areas that should be regenerated.
• Outpainting: add missing space around existing frames.

If a Video Mask is provided, the selected process can apply only to the masked area or only to the non-masked area. This lets you keep a subject while changing the background, replace one person among several people, or combine different effects inside and outside the mask.

WanGP previews processed Control Video and Video Mask thumbnails before generation. Use --save-masks when you need to inspect the full generated control media.

Masks

Masks decide where a process applies.

• Black areas are usually preserved.
• White areas are usually processed.
• Some model families support colored masks to identify several people or objects independently.

For person or object replacement, a stable mask across frames is usually more important than a perfect mask on one frame.

Matanyone is useful for creating Video Masks:

1. Load the source video.
2. Select the face, person, object, or region in the first frame.
3. Validate the mask.
4. Generate the matting video.
5. Export the source video and mask back into the Control Video and Video Mask inputs.

Mask tips:

• Use negative point prompts to remove unwanted parts from a selection.
• Use sub masks when one selection is too hard to define cleanly.
• Use mask expansion or shrinking when the generated replacement needs more or less room than the original subject.

Reference Images

Reference images can represent a subject, object, landscape, style source, or exact frame position. Their role should be clear in the prompt.

Use foreground cleanup for:

• People or objects that should be inserted into a generated scene.
• References where the original background should not influence the output.
• Character or object swaps where a clean foreground improves identity and placement.

Avoid foreground cleanup for:

• Landscape, room, or setting references.
• Background images that should define the environment.
• Injected frames that should appear as complete frames at a specific position.

If automatic cleanup is not precise enough, use the Image version of Matanyone to create a cleaner foreground mask.

During Generation: Temporal And Spatial Processing

Generation-time processing changes what the model adds, keeps, or regenerates while it is producing the output.

Temporal Processing

Temporal processing controls frames over time.

• Temporal Outpainting: adds frames before or after existing media. It is implicit when you continue a Source Video or provide a Control Video shorter than the requested output.
• Temporal Inpainting: fills missing frames between existing frames.
• Injected Reference Frames: places specific images at chosen frame positions so the model can fill the gaps between them.
• Frames To Keep: preserves selected Control Video frames and regenerates the others.

When a model supports positioned frames, frame positions are counted from the first frame of the active timeline. In sliding-window workflows, this usually means the first frame of the first window.

Spatial Processing

Spatial processing controls image regions or canvas size.

• Spatial Outpainting: adds new content to the top, bottom, left, or right of existing frames.
• Inpainting: replaces masked image regions.
• Mask Expansion / Shrinking: adjusts the editable area when the replacement subject is larger or smaller than the original target.
• Reference Image Placement: uses injected frames or reference images to guide what appears in newly generated areas.

Spatial outpainting targets the resolution you request. If the requested resolution is the same as the source media, the original content may lose detail because canvas space is being reallocated. For outpainting, a higher output resolution is often useful.

Sliding Windows For Long Videos

Sliding windows let WanGP generate longer videos by merging multiple generation windows.

The longer the video, the more likely quality is to degrade over time. The effect is usually less visible when the generated video mostly preserves unmodified control-video content.

When sliding windows are enabled, positional arguments such as injected-frame positions or frames to keep are usually relative to the first frame of the first window. This lets you change the sliding-window size without recalculating all frame positions.

If you continue from a Source Video, the Source Video is treated as the first window. The overlap size controls how many frames from that source or previous window are used to condition the next generated segment.

How sliding windows work:

• Each window uses the matching time segment of the Control Video.
• Example: 0-4s control video -> first window, 4-8s -> second window.
• Overlap management helps smooth transitions between windows.

Generated frame count formula:

Generated Frames = [Nb Windows - 1] x [Window Size - Overlap - Discard] + Window Size

Multi-line prompts can be used when the model supports assigning one prompt line per sliding window. If there are more windows than prompt lines, the last prompt line repeats.

Sliding-window settings:

• Window Size: choose a duration that fits the motion and model quality.
• Overlap Frames: use enough overlap for continuity, but not so much that blur propagates.
• Discard Last Frames: remove weak final frames from each window when a model tends to blur at the end.
• Add Overlapped Noise: may help some workflows, but can reduce quality in others.

After Generation: Postprocessing

Postprocessing is applied after media exists. It can run immediately after generation or later from the Media Info / Late Post Processing area.

Use postprocessing when the content is good but the final media needs a technical or finishing pass.

Common postprocessing jobs:

• Spatial upsampling for images or videos.
• Video frame interpolation or temporal upsampling.
• Audio postprocessing, voice replacement, or soundtrack remuxing.
• Cropping, resizing, or importing existing media for a later workflow.
• Applying a system postprocessing model through MediaFlow.

Late postprocessing is useful when you want to improve existing media without regenerating the original scene.

Checklists

Before generation:

• Preview processed Control Video and Video Mask thumbnails.
• Confirm masks apply to the intended region.
• Check that reference images match the role described in the prompt.
• Use --save-masks when the preview is not enough.

Before a long sliding-window run:

• Test a short window first.
• Confirm frame positions are measured from the intended timeline start.
• Pick enough overlap for continuity.
• Avoid excessive overlap when blur propagates.

After generation:

• Check that outputs are visually usable, not only valid files.
• Use late postprocessing when resolution, audio, or motion needs refinement.
• Keep the original generation output when trying multiple postprocessing passes.

Troubleshooting

If windows are inconsistent:

• Increase overlap frames.
• Keep prompts consistent across windows.
• Reduce discard frames if too much useful content is lost.
• Add overlapped noise only if it helps the specific workflow.

If results are blurry:

• Reduce excessive overlap.
• Increase discarded end frames for models that blur at window ends.
• Use higher-quality reference images or control videos.
• Verify that preprocessing did not resize the useful region too aggressively.

If masks do not behave as expected:

• Inspect the preview thumbnails.
• Save masks and control videos with --save-masks.
• Rebuild the mask with cleaner selections or sub masks.
• Expand or shrink the mask when the replacement subject needs different space.