xel_format</samp>&rsquo;</dt>
<dd><p>Select pixel format to be used by DirectShow. This may only be set when
the video codec is not set or set to rawvideo.
</p>
</dd>
<dt>&lsquo;<samp>audio_buffer_size</samp>&rsquo;</dt>
<dd><p>Set audio device buffer size in milliseconds (which can directly
impact latency, depending on the device).
Defaults to using the audio device&rsquo;s
default buffer size (typically some multiple of 500ms).
Setting this value too low can degrade performance.
See also
<a href="http://m