The SDP Anatomy post originally by Antón Román has long been one of our most popular pages. The interactive guide was originally written in PHP, but became outdated and has some techincal issues. I rewrote the page in JavaScript and set to to pull data from Github to make updates easier. Antón and Fippo helped to update some of the SDP data to match the latest specs and implementations.
We have Antón Román discuss more about it here at: https://webrtchacks.com/update-anatomy-webrtc-sdp-anton-roman/