gif

Video to GIF

ultrathink

Convert screen recordings to compressed GIFs using ffmpeg's two-pass palette method. Handles HDR (HDR10/PQ) recordings from macOS automatically.

Environment

• ffmpeg: !which ffmpeg 2>/dev/null && ffmpeg -version 2>&1 | head -1 || echo "NOT INSTALLED - run: brew install ffmpeg"

If ffmpeg is NOT INSTALLED, stop immediately and tell the user to install it. Do not attempt any conversion.

Defaults

Setting	Value	Notes
FPS	10	Good for screen recordings
Width	640px	Lanczos scaling
Speed	1x	No speedup
Palette	stats_mode=diff	Optimizes for static areas
Dither	bayer:bayer_scale=5	Good quality, small file

Parse arguments from the user's invocation:

• --speed N → playback speed multiplier (default: 1). Use 2-4x for long demos.
• --width N → override scale width (default: 640)
• --fps N → override frame rate (default: 10)
• --full → no scaling, keep original resolution
• --crop → crop out macOS screen recording overlay (top bar). Probe dimensions first, then apply crop=in_w:in_h-PIXELS:0:PIXELS to remove the top PIXELS.

Quick Workflow

Parse the video path from $ARGUMENTS.

IMPORTANT: File paths with spaces, timestamps, and special characters are problematic. ALWAYS use the glob+copy pattern.

Step 1: Copy + Probe

Extract a unique identifier from the user's path (like a timestamp) and use glob:

/bin/cp -f /path/to/dir/*UNIQUE_PART* /tmp/video.mov && \
ffprobe -v error -select_streams v:0 \
  -show_entries stream=width,height,r_frame_rate,duration \
  -show_entries stream=color_transfer \
  -of default=noprint_wrappers=1 /tmp/video.mov

Example for Screen Recording 2026-01-29 at 12.33.07 PM.mov:

/bin/cp -f ~/Desktop/Screen*12.33.07* /tmp/video.mov && \
ffprobe -v error -select_streams v:0 \
  -show_entries stream=width,height,r_frame_rate,duration \
  -show_entries stream=color_transfer \
  -of default=noprint_wrappers=1 /tmp/video.mov

Check the color_transfer value:

• smpte2084 → HDR recording, must convert to SDR first (Step 1b)
• Anything else (bt709, unknown, etc.) → SDR, skip to Step 2

Step 1b: HDR → SDR conversion (only if color_transfer=smpte2084)

macOS screen recordings on XDR displays use HDR10 (PQ/BT.2020/10-bit). The base Homebrew ffmpeg cannot tone-map PQ without the zimg library. Use macOS-native avconvert instead. It uses AVFoundation which handles HDR to SDR tone mapping correctly.

avconvert -s /tmp/video.mov -o /tmp/video_sdr.mov -p PresetHighestQuality --replace --progress

Then use /tmp/video_sdr.mov as input for Step 2 instead of /tmp/video.mov.

Verify conversion:

ffprobe -v error -select_streams v:0 -show_entries stream=color_transfer -of csv=p=0 /tmp/video_sdr.mov

Should output bt709 (not smpte2084).

Step 2: Convert to GIF (two-pass palette method)

Use /tmp/video_sdr.mov if HDR was detected, otherwise /tmp/video.mov. Substitute the input path as INPUT below.

Build the filter chain from arguments. Omit setpts when speed is 1. Omit crop when not requested.

Filter chain order: setpts → crop → fps → scale → palettegen/paletteuse

With defaults (fps=10, width=640, speed=1):

mkdir -p /tmp/gif-output && \
ffmpeg -y -v warning -i INPUT \
  -vf "fps=10,scale=640:-1:flags=lanczos,palettegen=stats_mode=diff" \
  -update 1 /tmp/gif-output/palette.png && \
ffmpeg -y -v warning -i INPUT -i /tmp/gif-output/palette.png \
  -lavfi "fps=10,scale=640:-1:flags=lanczos[x];[x][1:v]paletteuse=dither=bayer:bayer_scale=5" \
  -loop 0 /tmp/gif-output/output.gif && \
du -h /tmp/gif-output/output.gif

With --speed 3 (3x speedup):

mkdir -p /tmp/gif-output && \
ffmpeg -y -v warning -i INPUT \
  -vf "setpts=PTS/3,fps=10,scale=640:-1:flags=lanczos,palettegen=stats_mode=diff" \
  -update 1 /tmp/gif-output/palette.png && \
ffmpeg -y -v warning -i INPUT -i /tmp/gif-output/palette.png \
  -lavfi "setpts=PTS/3,fps=10,scale=640:-1:flags=lanczos[x];[x][1:v]paletteuse=dither=bayer:bayer_scale=5" \
  -loop 0 /tmp/gif-output/output.gif && \
du -h /tmp/gif-output/output.gif

With --full (no scaling):

mkdir -p /tmp/gif-output && \
ffmpeg -y -v warning -i INPUT \
  -vf "fps=10,palettegen=stats_mode=diff" \
  -update 1 /tmp/gif-output/palette.png && \
ffmpeg -y -v warning -i INPUT -i /tmp/gif-output/palette.png \
  -lavfi "fps=10[x];[x][1:v]paletteuse=dither=bayer:bayer_scale=5" \
  -loop 0 /tmp/gif-output/output.gif && \
du -h /tmp/gif-output/output.gif

With --crop (remove macOS recording overlay): Insert crop before fps. The macOS recording bar is typically ~60px on retina displays:

# crop=in_w:in_h-PIXELS:0:PIXELS removes top PIXELS from source
"setpts=PTS/3,crop=in_w:in_h-60:0:60,fps=10,scale=640:-1:flags=lanczos,palettegen=stats_mode=diff"

Step 3: Report

Report the output path and file size. Then open:

open /tmp/gif-output/output.gif  # macOS

Size Reduction Tips

For large or long videos:

Technique	Command modification
Speed up	setpts=PTS/3 for 3x (fewer frames = smaller file)
Lower FPS	fps=5 (for long videos)
Smaller width	scale=480:-1 or scale=320:-1
Trim to range	Add -ss 00:00:05 -t 10 before -i to grab 10s starting at 5s
Crop region	Add crop=w:h:x:y to the filter chain
Remove overlay	crop=in_w:in_h-60:0:60 removes top 60px (macOS recording bar)

Gotchas

• avconvert is macOS-only. On Linux, HDR tone mapping requires ffmpeg built with zimg or libplacebo, which Homebrew/apt default builds lack.
• --full on retina screen recordings (2880x1800+) produces GIFs over 100MB. Always warn about file size when skipping the scale filter.
• The two-pass palette method writes /tmp/gif-output/palette.png and /tmp/gif-output/output.gif but never cleans them up. Repeated runs overwrite, but stale files persist across sessions.
• scale=640:-1 fails when the source height is odd after scaling. Use scale=640:-2 to force even dimensions.
• --crop assumes 60px for the macOS recording bar, but this varies by display scale and macOS version. Always probe actual dimensions and let the user confirm the crop value.