p>&rsquo; or &lsquo;<samp>abs_wallclock</samp>&rsquo;.
Defaults to &lsquo;<samp>video</samp>&rsquo;.
</p>
</dd>
<dt>&lsquo;<samp>audio_pts</samp>&rsquo;</dt>
<dd><p>Sets the audio packet timestamp source. Must be &lsquo;<samp>video</samp>&rsquo;, &lsquo;<samp>audio</samp>&rsquo;,
&lsquo;<samp>reference</samp>&rsquo;, &lsquo;<samp>wallclock</samp>&rsquo; or &lsquo;<samp>abs_wallclock</samp>&rsquo;.
Defaults to &lsquo;<samp>audio</samp>&rsquo;.
</p>
</dd>
<dt>&lsquo;<samp>draw_bars</samp>&rsquo;</dt>
<dd><p>I