The etro.Movie class is used to render layers and effects into a single video blob. When creating a movie, a canvas to render to is required:

var canvas = document.createElement('canvas')
var movie = new etro.Movie({ canvas )})

From here, you can either set the width and height on the canvas or the movie to adjust the dimensions:

movie.width = 200  // also sets the canvas's width to 200
movie.height = 200  // also sets the canvas's height to 200

Now we have a 200x200 movie, but there are no layers so nothing will be rendered. In the next section, we'll add a video clip to the movie.