canvas: include height and width for adaptive bitrate formats?

[jronallo]

I've included a height and width for adaptive bitrate formats, but
what I really mean is the maximum height and width that's provided for
those formats. It might be useful to have those max (and maybe min) values available?

See an example canvas here: https://gist.github.com/jronallo/b455a5ddab2ce4b28d55c7708603f85a