Copy copies any file from a path (which may be a URL) and returns a path inside dir containing the file.

DumpWAV stores the audio as a WAV in a temporary directory and returns the path.

Fetch calls Recode if path ends with .wav, otherwise Copy.

Load loads audio from an ffmpeg-decodable file from a path (which may be a URL).

Load loads audio from an ffmpeg-decodable file from a path (which may be a URL) and returns it at the given sample rate.

Recode copies an ffmpeg-decodable file from path (which may be a URL) and returns a path inside dir containing a FLAC encoded version of it.

Save stores the audio in the ffmpeg-encodable path.