MPlay has its own textport (Tools > Textport) you can use to script MPlay.
MPlay has no directory structure as there is in Houdini.
Viewers are named starting at
Viewports are numbered 0 to 15.
Commands unique to MPlay
Append a new image sequence to the sequence in the current viewport.
Load a new audio file, or change the audio options.
Load a new sequence into MPlay
Fit the MPlay window to the image(s) displayed in the viewport.
Home all the viewports.
Apply a profile to MPlay.
Prepend a sequence (insert a sequence before) the sequence in the current viewport.
List all the sequences currently loaded.
Set the component to display.
Set the plane to display.