sites supported by B<youtube-dl> may have different conventions for
their video formats.
+By default, youtube-dl will download the best available format; if you want
+to download the worst format to save bandwidth and time, use C<-f> I<worst>.
+
=item --all-formats
Downloads all formats for which a video may be available.
Do not use the I<Last-modified> header to set the file modification time.
+=item --extract-audio
+
+Create an audio-only file extracted from the video downloaded. Requires that
+ffmpeg and ffprobe be installed.
+
+=item --audio-format=B<FORMAT>
+
+Set the audio format to be used for the extraction. Possible values are
+I<best>, I<aac>, I<mp3>, with I<best> being the default.
+
=back
=head1 OUTPUT TEMPLATE