FFmpeg Video Watermark Remover

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name: video-watermark-remover description: Remove watermarks from videos using ffmpeg delogo filter. Use this skill whenever the user wants to remove a watermark from a video, asks to remove a logo/text overlay, sends a video with visible watermarks, or says "去除水印" / "remove watermark" / "去水印". Works for both fixed-position and dynamically-moving watermarks (segmented delogo approach). Does NOT remove transparent/AI-generated complex watermarks that require inpainting — those need a different pipeline.

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Video Watermark Remover

Remove watermark/logo/text overlays from videos using ffmpeg's delogo filter.

Core Logic

Step 1: Extract sample frames Extract frames at 1-second intervals to locate watermark positions:

for t in 1 2 3 4 5; do
  ffmpeg -y -ss 00:00:0$t -i "$INPUT" -frames:v 1 "/tmp/wm_frame_$t.jpg" 2>/dev/null
done

Step 2: Analyze with vision model Use the image tool to analyze the sample frames. Ask for:

Exact watermark positions (which corner/edge)

Pixel bounding box: x, y, width, height for a WxH resolution video

Whether watermarks are in the same position across all frames (fixed) or move (dynamic)

Step 3: Build segmentation strategy

*Fixed watermark* (same position throughout):

One delogo pass on entire video

*Dynamic watermark* (position changes at specific times):

Identify segment boundaries (e.g., 0-3.5s bottom-right, 3.5s+ left edge)

Process each segment separately with its own delogo coordinates

Concatenate segments back together

Step 4: Process and verify

# Single segment
ffmpeg -y -i "$INPUT" -vf "delogo=x=$X:y=$Y:w=$W:h=$H" -c:a copy "$OUTPUT"
Multiple segments
Process each segment separately with -ss/-t, then concat

Verify each segment's result with the vision model before final delivery.

Key Parameters

| Parameter | Description | |-----------|-------------| | x, y | Top-left corner of watermark region | | w, h | Width and height of watermark region | | INPUT | Input video path | | OUTPUT | Output video path |

Finding exact coordinates:

Vision model gives normalized coordinates on 0-1000 scale — convert to actual pixels

For a 720x1280 video: actual_x = normalized_x * width / 1000

Always add 5-10px padding to the detected region to ensure full coverage

Dynamic Watermark Segmentation

When watermark moves between distinct positions:

1. Identify transition points — Note which frames have watermarks at which positions 2. Create segments — Each position change = new segment boundary 3. Process each segment — Apply correct delogo coordinates to each time range 4. Concatenate — Use ffmpeg concat with a manifest file:

   file 'seg1.mp4'
   file 'seg2.mp4'
   

   ffmpeg -y -f concat -safe 0 -i concat.txt -c copy output.mp4
   

Example segmentation: | Segment | Time Range | Watermark Position | |---------|-----------|-------------------| | 1 | 0-3.5s | Bottom-right (x=540,y=1195,w=165,h=55) | | 2 | 3.5-5s | Left edge (x=30,y=480,w=160,h=210) |

Handling Multiple Watermarks

If multiple watermarks exist simultaneously (e.g., corner logo + username handle):

Identify which the user wants removed vs. preserved

Apply multiple delogo filters in the same vf string:

  -vf "delogo=x=540:y=1195:w=165:h=55,delogo=x=30:y=480:w=160:h=210"
  

Output Delivery

Save to /root/.openclaw/workspace/downloads/

Send via message tool with media parameter

Confirm with user before final delivery

Limitations

delogo fills the region with a blurred/averaged patch — works best on simple/static backgrounds

Semi-transparent watermarks, complex AI-generated watermarks, and moving watermarks over textured backgrounds may still show traces

For AI inpainting (natural content-aware fill): this skill cannot do it — inform the user and suggest inpainting pipeline if delogo result is unsatisfactory