HTML5 video is intended by its creators to become the new standard way to show video on the web without plugins - wikipedia 
<video width="400" controls> <source src="http://example.com/test.mp4" type="video/mp4"> Your browser does not support HTML5 video. </video> <p> Video courtesy of <a href="https://archive.org/details/viral_academy_dao-wiki-ipfs_prototyping viral academy" target="_blank">Ecobytes</a>. </p>
The HTML5 specification introduced the video element for the purpose of playing videos, partially replacing the object element.
WebM is generally preferred over Ogg Theora Vorbis when available, because it provides better compression to quality ratio and is supported by more browsers.
To install ffmpeg with VP8 support on OSX you can follow the instructions here renevolution.com
Please note that if you already installed FFmpeg with another command line, you will first need to run:
brew uninstall ffmpeg
See the example install shell commands below:
brew install ffmpeg --with-libvpx --with-libvorbis
or
brew install ffmpeg --with-fdk-aac --with-ffplay --with-freetype --with-frei0r --with-libass --with-libvo-aacenc --with-libvorbis --with-libvpx --with-opencore-amr --with-openjpeg --with-opus --with-rtmpdump --with-schroedinger --with-speex --with-theora --with-tools
Other Codecs
Formats like H.264, and Vorbis might also be subject to unknown patents.
This seems to be going backwards. Especially with Mozilla retiring PopcornJS. Here are a bunch of links: