Homebrew's ffmpeg formula has no libvorbis, and ffmpeg-full is keg-only

Fact

Homebrew's ffmpeg formula is a slim build; the optional libraries moved to ffmpeg-full, and libvorbis is one of them. The slim build still lists an encoder named vorbis — ffmpeg's native, experimental one — so a glance at ffmpeg -encoders looks fine, but anything that asks for libvorbis by name fails with Encoder not found. yt-dlp's --audio-format vorbis does exactly that, after downloading the whole source.

ffmpeg-full is keg-only: installing it puts nothing on PATH.

Why it matters

The error arrives at the end of a download and names neither the missing library nor the formula split, and the obvious fix — brew install ffmpeg-full — appears not to work because the old binary still answers.

How to apply

• Check for the exact encoder name before a long job: ffmpeg -hide_banner -encoders | grep -w libvorbis
• Use the full build explicitly: "$(brew --prefix ffmpeg-full)/bin/ffmpeg", or hand that directory to the tool (yt-dlp: --ffmpeg-location).
• Or prefer Opus, Vorbis's successor, which the slim formula supports.