Range: boolean - zero (false) or one (true)
If true, any difference between the aspect ratio of the mash and the player that's displaying it will be
accommodated by cropping out either the top and bottom edges or left and right edges.
If false, the mash will be scaled down such that it is all visible, leaving the player color underneath exposed.
This property is ignored if the aspect ratio of the mash and player are the same, in which case the mash is always scaled proportionately
to fit exactly.
config: url to a configuration file with a moviemasher tag
crop: boolean - zero (false) or one (true)
fps: integer frames per second
id: any alphanumeric string
quantize: integer frames per second