MP4 to GIF Conversion
Overview
Convert MP4 videos to high-quality GIFs using ffmpeg's two-pass palette method. The two-pass approach produces significantly better color quality than direct conversion.
When to Use
- User wants to convert MP4 (or other video) to GIF
- User needs to create GIFs from video for documentation, demos, or sharing
- User asks about reducing GIF file size or improving GIF quality
Prerequisites
- ffmpeg must be installed and available in PATH
Core Method
Two-pass palette-based conversion (always use this over single-pass):
# Pass 1: Generate optimized palette
ffmpeg -y -i <input> -vf "fps=15,scale=480:-1:flags=lanczos,palettegen=stats_mode=diff" /tmp/palette.png
# Pass 2: Convert using palette
ffmpeg -y -i <input> -i /tmp/palette.png -lavfi "fps=15,scale=480:-1:flags=lanczos [x]; [x][1:v] paletteuse=dither=bayer:bayer_scale=5:diff_mode=rectangle" <output>
Quick Reference
| Parameter | Default | Effect |
|---|---|---|
fps |
15 | Frame rate — lower = smaller file, choppier motion |
scale width |
480 | Output width in px — height auto-calculated (-1) |
lanczos |
— | High-quality downscaling filter |
stats_mode=diff |
— | Palette optimized for frame differences (better for motion) |
dither=bayer |
— | Ordered dithering, good balance of quality/size |
bayer_scale |
5 | Dither strength (0-5), higher = more dithering |
diff_mode=rectangle |
— | Only update changed regions (smaller file) |
Size vs Quality Tradeoffs
| Goal | Adjust |
|---|---|
| Smaller file | Lower fps (10), smaller width (320), or trim duration |
| Smoother motion | Higher fps (24-30), but file size increases significantly |
| Better colors | Use stats_mode=full for static/slow content |
| Sharper | Increase width (640-800), costs more file size |
Bundled Scripts
Two scripts are bundled alongside this SKILL.md. Use the one matching the current platform.
Windows (PowerShell) — mp4_to_gif.ps1:
& "<this-skill-dir>/mp4_to_gif.ps1" -InputFile <input> # Defaults: 480px, 15fps
& "<this-skill-dir>/mp4_to_gif.ps1" -InputFile <input> -Width 640 -Fps 20 # Custom settings
& "<this-skill-dir>/mp4_to_gif.ps1" -InputFile <input> -OutputFile <output> # Custom output name
Linux / macOS (Bash) — mp4_to_gif.sh:
bash "<this-skill-dir>/mp4_to_gif.sh" -i <input> # Defaults: 480px, 15fps
bash "<this-skill-dir>/mp4_to_gif.sh" -i <input> -w 640 -f 20 # Custom settings
bash "<this-skill-dir>/mp4_to_gif.sh" -i <input> -o <output> # Custom output name
When Claude invokes this skill, resolve <this-skill-dir> to the absolute path of the directory containing this SKILL.md.
Common Mistakes
- Single-pass conversion (
ffmpeg -i in.mp4 out.gif) — produces terrible banding and color artifacts. Always use the two-pass palette method. - Too high fps — 30fps GIFs are massive. 15fps is usually sufficient for demos.
- Too wide — 480px is good for most uses. Full 1080p GIFs are impractically large.
- Forgetting to clean up palette — Delete the temporary palette.png after conversion.