You can check the codec on your system but it does not tell you which one Elements is using.
Elements comes with all the most common codec you need.
There are but a few you need to install seperatly e.g. Mjpeg.
What is the issue you are having?
On a side not NEVER install a codec pack. It can mess up your system.
Thanx for replying, Ann!
My issue is that importing iPhone recordings doesn't work. Problems with .mov and m4a-files.
Elements requires Quicktime to be installed.
Do you have QT on your machine.
If not: install just the basics not the player.