tches streams that contain the given tag with any
value.
</p></dd>
<dt><samp>u</samp></dt>
<dd><p>Matches streams with usable configuration, the codec must be defined and the
essential information such as video dimension or audio sample rate must be present.
</p>
<p>Note that in <code>ffmpeg</code>, matching by metadata will only work properly for
input files.
</p></dd>
</dl>

<a name="Generic-options"></a>
<h3 class="section">3.2 Generic options<span class="pull-right"><a class="anchor hidden-xs" href="#Ge