While working on this, I thought about simplifying things like changing
480x854 to 480p, and that seemed like a good option, until I realized that
people (me included) usually link the concept of some number followed by a p
with the video being 16:9.
So, we would be losing some information and, as we all know,
[explicit is better than implicit][*].
[*]: http://www.python.org/dev/peps/pep-0020/
This closes#1446.
Signed-off-by: Rogério Brito <rbrito@ime.usp.br>