The new scripting system in LMMS allows you to run javascript inside of LMMS. You can generate beats and notes, and call external an external process like mplayer, which on Linux allows you to embed the mplayer window into the LMMS workspace.
above blender2.8 embedded inside of LMMS
above: amsynth, hydrogen, and vlc inside of LMMS
LMMS X11 Scripting Fork
