Uncomment different blocks of html to see the different options. Browsers start to struggle and you'll see weird issues when you have multiple video elements playing the same video file.
Every video is inside a 400px by 300px div.
1. No dimensions, preload: none
<video preload="none">
Should start with the default size (300x150), then resize to the content dimensions after playing.
(uncomment other html blocks to see other options)