Transcodes any local video file into a small, progressively streamable web-friendly copy — the house recipe for videos that play inside a federated wiki `HTML5 mp4 <url>` video item. Lives at `~/.claude/skills/video-ffmpeg`.
## When it triggers "transcode for web", "make a low-res copy", "420px video", "shrink this video for the wiki", "web-friendly version", "compress this video for a wiki page" — or when another skill (e.g. youtube-archive) needs a small progressive-download video for a page assets folder. Also covers remuxing an already web-native file (h264/aac) without re-encoding.
## What it does Probes the source with `ffprobe` first (codecs, dimensions, audio codec decide the rest). Default recipe scales to 420px wide, H.264 video at crf 28, `+faststart` (mandatory so the wiki's `<video>` element can start playing before the file finishes downloading), and copies the audio stream unchanged by default — no re-encode, no normalising, unless the source audio isn't AAC and the target is mp4, in which case it re-encodes audio to AAC for compatibility.
For a source that's already web-native H.264 + AAC in mp4 (e.g. a "highest quality" download), it skips re-encoding entirely and just remuxes the container. Loudness normalisation (`loudnorm`) is documented but off by default — only applied if explicitly asked for. After transcoding it reports output dimensions, codecs, file size, and the size reduction from source.
# See
# Assets
video-ffmpeg-skill