t>&lsquo;<samp>-ast <var>audio_stream_specifier</var></samp>&rsquo;</dt>
<dd><p>Select the desired audio stream using the given stream specifier. The stream
specifiers are described in the <a href="#Stream-specifiers">Stream specifiers</a> chapter. If this option
is not specified, the &quot;best&quot; audio stream is selected in the program of the
already selected video stream.
</p></dd>
<dt>&lsquo;<samp>-vst <var>video_stream_specifier</var></samp>&rsquo;</dt>
<dd><p>Select the desired video stream using t