Using shell commands, you could play media (audio and video) inside the window of a stack in Lubuntu 13.10
For mPlayer:
shell("mplayer -wid 25166356 -ontop -noborder -geometry 50%:50% -quiet -ss 12 -xy 0.5 mymovie.mp4")
For VLC:
shell("vlc -I dummy --play-and-exit --drawable-xid 23069197 mymovie.mp4 ")
Notice these switchs: -wid 25166356 and --drawable-xid 23069197
It tells to mplayer and VLC, which windows must use to play the media file.
To play media inside a stack, we need the LiveCode stack´s windows ID:
put the windowid of topstack
This function returns a number like: 25166356
Interesting enough, the movie resizes itself when we change the stack size. In Lubuntu, using the mouse pointer, we could move and resize freely the stack while the movie is playing , with VLC it´s possible to stop, pause, rewind, forward, change volume, etc... using the keyboard keys. Do not works with mPlayer, at least in the version installed from the CD.
Could you try these shell command in your own setup and report your results back?
Read both manuals, if you want to test many others commands:
http://www.mplayerhq.hu/DOCS/man/en/mplayer.1.html
https://wiki.videolan.org/VLC_command-line_help/
Now, we only need a reliable way to control the movie inside the stack, without using direct shell commands that completely blocks LiveCode while the media is playing. Warren Samples suggested that using FIFO or Sockets this is feasible.
Let´s hope that one of the experts in sockets and inter-application communication reads this thread and finds time to help.

A Media Player floating inside his own stack window is useful in many ways, until an embedded player became available.
We just need a better way to control it.
Thanks in advance!
Al