\texttt{Player} from different streams at different times. The
\texttt{AudioMerger} just accepts data, mixes and spits it out
again.
+\item \texttt{AudioMerger} made aware of periods with no content to
+ allow referenced reels; adds a fair amount of complexity. Without
+ this the referenced reel gaps are silence-padded which confuses
+ things later on as our VF DCP gets audio data that it does not need.
\item Obvious consumer changes: what was a loop over the playlist
length and calls to \texttt{get()} is now calls to \texttt{pass()}.
\item Maybe-seek stuff gone.