Add Video Inpaint mode for per-pixel spatial mask regeneration

New 9th mode that works at the pixel level rather than the frame level.
Accepts an optional MASK input (B,H,W) to mark spatial regions for
regeneration, with single-frame broadcast, spatial dimension validation,
and contiguous output tensors.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

README.md

@@ -18,10 +18,11 @@ Restart ComfyUI. The node appears under the **VACE Tools** category.
 | Input | Type | Default | Description |
 |---|---|---|---|
 | `source_clip` | IMAGE | — | Source video frames (B, H, W, C tensor) |
-| `mode` | ENUM | `End Extend` | Generation mode (see below). 8 modes available. |
+| `mode` | ENUM | `End Extend` | Generation mode (see below). 9 modes available. |
-| `target_frames` | INT | `81` | Total output frame count for mask and control_frames (1–10000). Unused by Frame Interpolation and Replace/Inpaint. |
+| `target_frames` | INT | `81` | Total output frame count for mask and control_frames (1–10000). Unused by Frame Interpolation, Replace/Inpaint, and Video Inpaint. |
 | `split_index` | INT | `0` | Where to split the source. Meaning varies by mode. Unused by Edge/Join. Bidirectional: frames before clip (0 = even split). Frame Interpolation: new frames per gap. Replace/Inpaint: start index of replace region. |
-| `edge_frames` | INT | `8` | Number of edge frames for Edge and Join modes. Replace/Inpaint: number of frames to replace. Unused by End/Pre/Middle/Bidirectional/Frame Interpolation. |
+| `edge_frames` | INT | `8` | Number of edge frames for Edge and Join modes. Replace/Inpaint: number of frames to replace. Unused by End/Pre/Middle/Bidirectional/Frame Interpolation/Video Inpaint. |
+| `inpaint_mask` | MASK | *(optional)* | Spatial inpaint mask for Video Inpaint mode (B, H, W). White (1.0) = regenerate, Black (0.0) = keep. Single frame broadcasts to all source frames. |
 
 ### Outputs
 
@@ -206,6 +207,33 @@ control_frames: [ before frames  ][ GREY  × replace ][ after frames  ]
 | `segment_3` | After — source[start+length:] |
 | `segment_4` | Placeholder |
 
+---
+
+### Video Inpaint
+
+Regenerate **spatial regions** within frames using a per-pixel mask. Unlike other modes that work at the frame level (entire frames kept or generated), Video Inpaint operates at the pixel level — masked regions are regenerated while the rest of each frame is preserved.
+
+- **`inpaint_mask`** *(required)* — a `MASK` (B, H, W) where white (1.0) marks regions to regenerate and black (0.0) marks regions to keep. A single-frame mask is automatically broadcast to all source frames; a multi-frame mask must have the same frame count as `source_clip`.
+- **`target_frames`**, **`split_index`**, **`edge_frames`** — unused.
+- **`frames_to_generate`** = `source_frames` (all frames are partially regenerated).
+- **Total output** = `source_frames` (same length — in-place spatial replacement).
+
+Compositing formula per pixel:
+
+```
+control_frames = source × (1 − mask) + grey × mask
+```
+
+```
+mask:           [ per-pixel mask broadcast to (B, H, W, 3)        ]
+control_frames: [ source pixels where mask=0, grey where mask=1   ]
+```
+
+| Segment | Content |
+|---|---|
+| `segment_1` | Full source clip |
+| `segment_2`–`4` | Placeholder |
+
 ## Dependencies
 
 None beyond PyTorch, which is bundled with ComfyUI.

nodes.py

@@ -58,10 +58,11 @@ class VACEMaskGenerator:
                         "Bidirectional Extend",
                         "Frame Interpolation",
                         "Replace/Inpaint",
+                        "Video Inpaint",
                     ],
                     {
                         "default": "End Extend",
-                        "description": "End: generate after clip. Pre: generate before clip. Middle: generate at split point. Edge: generate between reversed edges (looping). Join: generate to heal two halves. Bidirectional: generate before AND after clip. Frame Interpolation: insert generated frames between each source pair. Replace/Inpaint: regenerate a range of frames in-place.",
+                        "description": "End: generate after clip. Pre: generate before clip. Middle: generate at split point. Edge: generate between reversed edges (looping). Join: generate to heal two halves. Bidirectional: generate before AND after clip. Frame Interpolation: insert generated frames between each source pair. Replace/Inpaint: regenerate a range of frames in-place. Video Inpaint: regenerate masked spatial regions across all frames (requires inpaint_mask).",
                     },
                 ),
                 "target_frames": (
@@ -70,7 +71,7 @@ class VACEMaskGenerator:
                         "default": 81,
                         "min": 1,
                         "max": 10000,
-                        "description": "Total output frame count for mask and control_frames. Unused by Frame Interpolation and Replace/Inpaint.",
+                        "description": "Total output frame count for mask and control_frames. Unused by Frame Interpolation, Replace/Inpaint, and Video Inpaint.",
                     },
                 ),
                 "split_index": (
@@ -91,10 +92,18 @@ class VACEMaskGenerator:
                         "description": "Number of edge frames to use for Edge and Join modes. Unused by End/Pre/Middle. Replace/Inpaint: number of frames to replace.",
                     },
                 ),
-            }
+            },
+            "optional": {
+                "inpaint_mask": (
+                    "MASK",
+                    {
+                        "description": "Spatial inpaint mask for Video Inpaint mode. White (1.0) = regenerate, Black (0.0) = keep. Single frame broadcasts to all source frames.",
+                    },
+                ),
+            },
         }
 
-    def generate(self, source_clip, mode, target_frames, split_index, edge_frames):
+    def generate(self, source_clip, mode, target_frames, split_index, edge_frames, inpaint_mask=None):
         B, H, W, C = source_clip.shape
         dev = source_clip.device
         BLACK = 0.0
@@ -199,6 +208,30 @@ class VACEMaskGenerator:
             control_frames = torch.cat([before, solid(length, GREY), after], dim=0)
             return (mask, control_frames, safe(before), safe(source_clip[start:end]), safe(after), ph(), frames_to_generate)
 
+        elif mode == "Video Inpaint":
+            if inpaint_mask is None:
+                raise ValueError("Video Inpaint mode requires the inpaint_mask input to be connected.")
+            m = inpaint_mask.to(dev)                       # (Bm, Hm, Wm) MASK type
+            if m.shape[1] != H or m.shape[2] != W:
+                raise ValueError(
+                    f"Video Inpaint: inpaint_mask spatial size {m.shape[1]}x{m.shape[2]} "
+                    f"doesn't match source_clip {H}x{W}."
+                )
+            m = m.clamp(0.0, 1.0)
+            if m.shape[0] == 1 and B > 1:
+                m = m.expand(B, -1, -1)                    # broadcast single mask to all frames
+            elif m.shape[0] != B:
+                raise ValueError(
+                    f"Video Inpaint: inpaint_mask has {m.shape[0]} frames but source_clip has {B}. "
+                    "Must match or be 1 frame."
+                )
+            m3 = m.unsqueeze(-1).expand(-1, -1, -1, 3).contiguous()  # (B,H,W) -> (B,H,W,3)
+            mask = m3
+            grey = torch.full_like(source_clip, GREY)
+            control_frames = source_clip * (1.0 - m3) + grey * m3
+            frames_to_generate = B
+            return (mask, control_frames, source_clip, ph(), ph(), ph(), frames_to_generate)
+
         raise ValueError(f"Unknown mode: {mode}")