o wait until the number of online sources have changed.
Defaults to &lsquo;<samp>0.5</samp>&rsquo;.
</p>
</dd>
<dt>&lsquo;<samp>allow_video_fields</samp>&rsquo;</dt>
<dd><p>When this flag is &lsquo;<samp>false</samp>&rsquo;, all video that you receive will be progressive.
Defaults to &lsquo;<samp>true</samp>&rsquo;.
</p>
</dd>
</dl>

<a name="Examples-2"></a>
<h3 class="subsection"><a href="ffmpeg-devices.html#toc-Examples-2">3.7.2 Examples</a></h3>

<ul>
<li>
List input devices:
<div class="example">
<pre 