@eagerhalfling Clearly we are back to the bad old days where none of the basics work and you have to find out yourself.
You have made the right start by asking questions . I found no youtube videos or facebook videos played properly and even vids on mail.com would not even play. Silly infighting really ,people hell bent on making dollars out of you so you have to outsmart them.
Here is what I got that fixed my problems.
http://launchpadlibrarian.net/378344065/chromium-codecs-ffmpeg-extra_67.0.3396.99-0ubuntu0.16.04.2_amd64.deb
Note the "chromium-codecs-ffmpeg-extra_67.0.3396.99".
Looks like this is one of the workarounds for proprietary shit that you need to find a version for your operating system and install it.
Here is what is said about it on the download site
This package contains the multi-threaded ffmpeg codecs needed for the HTML5
<audio> and <video> tags. In addition to the patent-free ogg, vorbis and
theora codecs, aac/ac3/mpeg4audio/h264/mov/mp3 are also included. See
chromium-codecs-ffmpeg if you prefer only the patent-free codecs