HTML5 background video encoding settings I'm doing a full page background video and I'm trying to convert the original mp4 to an webm. The background will not have any audio. 

I'm currently using ffmpeg.

ffmpeg -i INPUT.mp4 -b 614400 -s 960x540 -aspect 16:9 OUTPUT.webm


My question is what are the optimal settings to convert an mp4 to an webm file that will be used as a background video on a website?
There shouldn't be anything special about making a video for HTML5 video, so just look for any video encoding guide to learn about choosing how to trade off CPU time vs. bitrate vs. quality.

Hint: encode once, display many is a use case where it makes sense to spend as much CPU time as possible on the encode, to get the quality you want in as small a download as possible.