 left then flows to a red box labeled Video
Decoder, which then flows to a switch that selects between one of three inputs,
and the output of the switch connects to an output destination, labeled Video Tag
Display Region. The switch indicates that one Video Decoder output (from
SourceBuffer 2) is selected to flow into the Video Tag Display Region.</p>

<p>The second Track Buffer flows to a green box labeled Audio Decoder, which
then follows to an indicator of an open switch, which then continues to a
summin