A Solution to Play Some Streaming Videos Which Do Not Play on Ubuntu

While using Ubuntu, the last version, you may encounter that everything works perfect on YouTube. But if you encountered some streaming videos can not be played on some sites in Ubuntu, now you have a solution.

Ubuntu needs a video library to be installed  to play all the videos on all ths web sites. Installing "libavcodec-extra" package in package manager or using following command in terminal solves this issue: 

< sudo apt install libavcodec-extra >