Background Sound Keyword
The frame's definition and contents exactly parallel a Sound Frame's, any keyword appropriate there is
appropriate here. The difference is that the <BackgroundSound>
has no other effect other than to start playing the specified wave file in a
looped fashion, continuously. As far as DMDX's presentation is concerned the frame does not exist.
Once a frame with this keyword has been parsed DMDX will play the
sound continually, that is the sound will commence before the item displays as
DMDX waits for the previous item's request. If there is no filename
present in a <BackgroundSound>
specification the current background sound will be stopped.