# Tifenke Watermark Remover

> Remove faint gray watermarks from 提分课 course videos by normalizing light backgrounds and the green design palette while retaining yellow headers, green panels, white/black text, red annotations, source dimensions, frame rate, and audio. Use when the user says 提分课去水印, asks to process a 提分课 video like the verified 黄绿保留融合版, or wants a pale watermark merged into white and green backgrounds without preserving exact original colors.

- Skill: `sangjiexun/tifenke-watermark-remover` (Agent Skill, multi-file: 3 files)
- Install (CLI): `npx skillmds@latest add sangjiexun/tifenke-watermark-remover`
- Raw SKILL.md: https://api.skillmd.com/api/skills/sangjiexun/tifenke-watermark-remover/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: sangjiexun (https://skillmd.com/u/sangjiexun)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/sangjiexun/tifenke-watermark-remover

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# 提分课去水印

Use the verified color-normalization workflow for 提分课 screen-recorded course videos. It makes the pale watermark indistinguishable from the surrounding white or green background.

## Workflow

1. Work from the original local video, never an already processed export.
2. Probe dimensions, frame rate, duration, frame count when available, and audio.
3. Inspect frames near the beginning, middle, and end. Check for source green near `0x8AC952`, watermark-tinted green near `0x80BC4D`, a pale gray watermark on white, yellow headers, black/white text, and possibly red annotations.
4. If the palette matches, run `scripts/remove-tifenke-watermark.ps1`.
5. If green differs materially, sample unobstructed green and watermark-overlaid green. Pass them as `-SourceGreen` and `-TargetGreen`. Test a short clip first.
6. Inspect all generated verification frames. Confirm the watermark disappears on light and green areas while content remains legible.
7. Report the output path and verification result.

## Standard command

```powershell
powershell -NoProfile -ExecutionPolicy Bypass -File "<skill-dir>\scripts\remove-tifenke-watermark.ps1" -InputPath "<video.mp4>"
```

Default output: `<source-folder>\edit\<source-name>_去水印_黄绿保留融合版.mp4`.

Use `-Overwrite` only when the user explicitly wants to replace an existing export.

## Verified transform

```text
color=c=0x80BC4D:s=<width>x<height>:r=<fps>[bg];
[0:v]format=rgba,colorkey=0x8AC952:0.12:0.025[key];
[bg][key]overlay=shortest=1,
lutyuv=y='if(gte(val,214),220,val)',
format=yuv420p
```

- Unify the source green family into the watermark-like green.
- Flatten luma at or above `214` to `220`, merging white and faint gray.
- Encode H.264 using `libx264`, `CRF 16`, `preset medium`, `yuv420p`, and `faststart`.
- Copy original audio without re-encoding.

## Quality rules

- Preserve width, height, frame rate, duration, and audio presence.
- Export from the original input.
- Prioritize watermark invisibility and content legibility, not exact color preservation.
- Do not apply the fixed palette blindly to people, photographs, gradients, or a substantially different theme. Inspect and adapt first.
- Treat duration difference over 0.25 seconds, missing audio, dimension mismatch, or frame-count mismatch as failed verification.
- If white text disappears, reduce `-Similarity` or `-Blend`. If green watermark remains, slightly increase `-Similarity` before changing luma thresholds.

## Useful options

```powershell
-OutputPath "D:\output\result.mp4"
-SourceGreen "0x8AC952" -TargetGreen "0x80BC4D"
-StartSeconds 295 -DurationSeconds 8
-Overwrite
```

The script prints a JSON summary and creates three JPEG verification frames beside the export in a `_验证帧` folder. Inspect them before declaring completion.