Sometimes it happens that after you install the Skype application and sample audio and video settings in it, abnormally play audio or video. Of course for these purposes there are standard settings, installed in Linux Mint by default: the sound Settings (volume) or Cheese (for video camera).
In this case, in the repositories of Ubuntu /Linuix Mint/PinguyOS is an app called Multimedia systems selector (gnome-media) Settings applications GStreamer by default.
But what to do if you are there all tried, but no change!?
As you can see in the pictures, there are two necessary tabs: Audio and Video. In each tab there is a check button to Check. You can test the Audio and Video by clicking on these buttons. If some settings are not working correctly, you can change them at its discretion in the value of the Module and re-press the button to Check, achieving the desired result.
Installation into Linux Mint:
Check capacity for work of audio and video settings
sudo apt install gnome-media
gstreamer-properties & exit