In LR 5.2, there are many bugs with videos and smart-collection dimension criteria. In particular, these criteria do not match any of the .mp4 and .avi videos I tested with:
Cropped is false
Long Edge is greater than 0
Short Edge is greater than 0
Width is greater than 0
Height is greater than 0
Width, Uncropped is greater than 0
Height, Uncropped is greater than 0
Megapixels is greater than 0.0
(Megapixels is defined for images simply as width x height / 1,000,000; should be the same for videos.)
Strangely, the following criteria do work correctly for the tested videos:
Long Edge, Uncropped greater than 0
Short Edge, Uncropped greater than 0
Megapixels, Uncropped is greater than 0.0
Aspect Ratio is landscape