Expand description
The one place that knows where ffmpeg is, and what to say when it is not.
ffmpeg is an external program, not a dependency. Nothing is linked, nothing is vendored, and a checkout without ffmpeg installed builds and passes its tests — the features that need it say so and stop. Copying, spectrum rendering and playback share these install instructions: a fact hand-copied into several places will eventually be wrong in one of them.
The search is deliberately plain — ffmpeg, on the PATH. A GUI
application has to hunt through /opt/homebrew/bin and the rest because it
is launched by Finder and inherits no shell environment; a command run from
a terminal inherits the user’s PATH by construction, and looking anywhere
else would only find a different ffmpeg from the one they get when they
type the name themselves. Playback uses it for formats that the native
decoder cannot open, currently Opus, AAC and ALAC.