Change the first selected node to 2's, presuming frame naming matches the default import values.

setVideoOn2s.js

scene.beginUndoRedoAccum("Set Video on 2s");

var col = node.linkedColumn(selection.selectedNode(0), "drawing.element");
var keys = column.getDrawingTimings(col);

keys.forEach(function(key) {
    if (parseInt(key) % 2 === 0) {
        column.setEntry(col, 1, parseInt(key), parseInt(key) - 1);
    }
});
scene.endUndoRedoAccum();