youtube_video_optimizer

Shrinks video files for uploading/streaming to YouTube. It's a thin wrapper around ffmpeg — ffmpeg does all the work; the script just fixes convenient presets and sensible defaults.

Install

brew install ffmpeg      # if you don't have it yet
chmod +x optimize.sh     # once

Usage

./optimize.sh video.mp4              # 720p (default)
./optimize.sh -r 1080 video.mp4      # 1080p
./optimize.sh -r 480 video.mp4       # 480p (maximum space saving)
./optimize.sh -q 25 video.mp4        # compress harder (higher CRF = smaller file)
./optimize.sh -p slow video.mp4      # slower encode, slightly smaller file
./optimize.sh -o out/ *.mp4          # batch, output into out/ folder

Flags: -r resolution (480/720/1080), -q CRF quality (lower = better), -p ffmpeg preset, -o output folder, -h help.

Drag-and-drop (macOS)

Build the app once — double-click build_droplet.command and it creates Optimize Video.app next to it (on first launch: right-click → "Open" to get past Gatekeeper).

After that, just drag video files onto the app icon → pick a resolution (480/720/1080) → done. You can drop the app into the Dock. Internally it calls optimize.sh, so both files must live in the same folder.

Sources: droplet.applescript (logic) and build_droplet.command (builder).

What it does

• H.264, -crf (constant quality): 480/720p → 23, 1080p → 22.
• Downscales only if the source is taller than the target (never upscales).
• Audio: if already AAC, copies it without re-encoding (no loss or clicks), otherwise re-encodes to AAC 160k.
• +faststart — moves the moov atom to the front, ready for streaming.
• Output name: <name>_optimized_<res>p.mp4.

For AI agents

The repo ships with agent support out of the box:

• AGENTS.md — instructions for any coding agent (Claude Code, Cursor, Codex, …): how to run the CLI, flags, behavior guarantees, conventions.
• .claude/skills/video-optimize/ — a Claude Code skill: ask Claude to "compress this video for YouTube" inside the repo and it will use optimize.sh with the right preset.

Benchmark

Meditative lofi, 68 min: 6.2 GB → 625 MB (−89%) at 720p with no visible quality loss. Source files often ship with an inflated bitrate (~12 Mbps for 720p vs. YouTube's recommended ~5 Mbps), which leaves plenty of headroom for compression.

License

MIT

Support

If this project was useful to you, feel free to support further development: