Install ffmpeg
Whisper reads audio. ffmpegis the tool that opens almost any audio or video file and feeds it to Whisper. It is the most common “why isn't this working” in this guide. We install it first. This is the hardest step on Windows. Stick with it.
Don't have brew? Run this one-liner first:
ffmpeg version 6.1 Copyright (c) 2000-2024 ...
built with Apple clang version 15.0.0 ...
ffmpeg is not recognized
The exe is on your disk but Windows doesn't know where to find it. Add the folder containing ffmpeg.exe to your PATH. In Settings → search “Edit environment variables” → User variables → Path → New → paste the folder path (e.g. C:\ffmpeg\bin). Close every open terminal and open a new one — PATH changes do not apply to already-open shells.