header. If not specified the protocol will use a
string describing the libavformat build. (&quot;Lavf/&lt;version&gt;&quot;)
</p>
</dd>
<dt>&lsquo;<samp>user-agent</samp>&rsquo;</dt>
<dd><p>This is a deprecated option, you can use user_agent instead it.
</p>
</dd>
<dt>&lsquo;<samp>timeout</samp>&rsquo;</dt>
<dd><p>Set timeout in microseconds of socket I/O operations used by the underlying low level
operation. By default it is set to -1, which means that the timeout is
not specified.
</p>
</dd>
<dt>&lsquo;<s