There's a new video codec HEVC (High Eficiency Video Codec), and certain media from "certain sources" come in that format.

To play that, you need the latest SW or firmware.

If you play these videos in VLC, then you're going to need VLC 2.2.x. Here's how to put it to Ubuntu 14.04:

https://launchpad.net/~mc3man/+archive/ubuntu/trusty-media/

In short:

sudo add-apt-repository ppa:mc3man/trusty-media
sudo apt-get update
sudo apt-get dist-upgrade

Pay the special attention to the note:

Please note that if using this ppa I would *not* try upgrading to 14.10/15.04, ect. Do a fresh install instead. The intent here is just for users wishing to stay on 14.04*

If upgrading anyway use ppa-purge first -

sudo ppa-purge ppa:mc3man/trusty-media

Then you need the codec itself:

sudo apt-add-repository ppa:strukturag/libde265
sudo apt-get update
sudo apt-get install vlc-plugin-libde265

This worked for me.

Enjoy. And don't forget to purge and remove these repos before upgrading to new Ubuntu version!